Open Access

Occlusal rehabilitation in patients with congenitally missing teeth—dental implants, conventional prosthetics, tooth autotransplants, and preservation of deciduous teeth—a systematic review

International Journal of Implant Dentistry20151:30

DOI: 10.1186/s40729-015-0025-z

Received: 25 July 2015

Accepted: 27 August 2015

Published: 18 November 2015

Abstract

Background

Implant patients with congenitally missing teeth share some common charateristics and deserve special attention.

Methods

The PICO question was “In patients with congenitally missing teeth, does an early occlusal rehabilitation with dental implants in comparison to tooth autotransplants, conventional prosthetics on teeth or preservation of deciduous teeth have better general outcomes in terms of survival, success and better patient centered outcomes in terms of quality of life, self-esteem, satisfaction, chewing function?”

After electronic database search, a total of 63 relevant studies were eligible, of which 42 qualified for numerical data synthesis, 26 being retrospective studies. A data synthesis was performed by weighted means for survival/success/annual failure rates.

Results

The mean survival of implants was 95.3 % (prosthesis survival 97.8 %), autotransplants 94.4 %, deciduous teeth 89.6 %, and conventional prostheses 60.2 %. The implant survival in children, adolescents, and adults was 72.4, 93.0, and 97.4 %. Annual failure rates of implants 3.317 %, autotransplants 1.061 %, deciduous teeth 0.908 %, and conventional prostheses 5.144 % indicated better results for natural teeth and more maintenance needs for the both prosthetic treatments. The mean OHIP score was 27.8 at baseline and a mean improvement of 14.9 score points was reported after implant prosthetics. The mean satisfaction rates were 93.4 (implants), 76.6 (conventional prostheses), 72.0 (autotransplants), and 65.5 % (orthodontic space closure).

Conclusions

In synopsis of general and patient-centered outcomes, implants yielded the best results, however, not in children <13 years. Autotransplants and deciduous teeth had low annual failure rates and are appropriate treatments in children and adolescents at low costs. Conventional prosthetics had lower survival/success rates than the other options. Due to heterogeneity and low number of studies, patient-reported outcomes in this review have to be interpreted with caution.

Keywords

Hypodontia Oligodontia Anodontia Tooth aplasia Tooth agenesis Congenitally missing teeth Tooth autotransplantation Deciduous tooth Dental implants Ectodermal dysplasia

Background

Congenitally missing teeth, also called hypodontia, is the most frequent human malformation. The prevalence of hypodontia in white populations is estimated to be 5.5 %, with a higher incidence in women than in men. Hypodontia varies in severity, from a single missing tooth to the absence of all permanent teeth called anodontia. Oligodontia is usually defined as the absence of 6 or more permanent teeth, the third molars excluded, and its prevalence is estimated at 0.14 % in the white population [1]. Hypodontia can occur in isolation (non-syndromal) or as a part of numerous inherited syndromes of which the different forms of ectodermal dysplasia are the predominant entity [2]. Patients with congenitally missing teeth comprise a special group of patients deserving special attention, especially when dental implants are needed.

In cases with congenitally missing teeth, the defect in the dentition occurs very early in life, in contrast to many other implant patients who lost their teeth due to caries or periodontitis at later stages. The early time point has an advantage that the young patients are usually well adapted to the defects. However, prosthetic treatments are often necessary already in childhood. In childhood and adolescence, prosthetic treatments can be complicated, because teeth should not be ground as abutments for crowns due to the large pulp cavity, and dentures may not be splinted if the jaws still grow. It is also questionable whether dental implants can be placed before termination of growth due to the well-known problems of secondary infraocclusion due to the ankylotic healing of osseointegrated implants and due to other biological reasons [3]. Furthermore, children and their young parents and families often have a cost problem, since unlike other implant patient groups, the tooth defects appear in early phases of life when the income is low or needed elsewhere. In some public health systems, occlusal rehabilitation in childhood and adolescence is covered by public insurances and has to be finished before the 18th year of life.

The local implant site can be special, too. A site with aplasia of the primary or secondary tooth usually is different from implant sites in conventional implant patients. Usually, there is a severe lack of alveolar bone width and often height and bone has never been there, since alveolar bone is unlike the basal jaw bone, a development of the erupting tooth. In addition, bone quality can be more cortical and brittle than in conventional implant sites, which can influence implant placement as well as orthodontic tooth movement. The same applies to the fixed masticatory gingiva in a site with tooth aplasia, which can be narrow or missing at all. Due to these common general properties of an implant site with tooth agenesis irrespective of the number of missing teeth, this systematic review includes articles with single or few missing teeth (mild hypodontia), multiple (>6) missing teeth (oligodontia), and also total absence of teeth (anodontia).

There may be mainly four or five treatment options for occlusal rehabilitation in cases with congenitally missing teeth, including dental implant-borne prosthetics. First option is the preservation of a primary deciduous tooth. Such decision has to be made first, if a primary tooth is still present in the site due to missing eruption of a permanent successor. A second option may be the autotransplantation of other teeth, if such transplants are available. This is a well-accepted method in childhood, since tooth autotransplants can heal with a functional periodontium which enables orthodontic movement and enables the tooth to participate in growth of the alveolar crest. Furthermore, tooth transplants in childhood have a better prognosis, when root development is still incomplete and the apical foramen is still open, compared to mature teeth in adults with closed foramen. A third option is conventional prosthetics on teeth, which in childhood will typically include unsplinted overdentures, which should not interfere with jaw growth or resin-bonded bridges, since juvenile teeth should not be ground for crowns. The fourth option is dental implants. Each of the four options has its advantages and limitations and a differential indication has to be made in every single case of congenitally missing teeth. The fifth option may be orthodontic space closure as a single treatment. Of course, adjunctive orthodontic treatment is a very important part of occlusal rehabilitation in patients with congenitally missing teeth. However, this is not in the focus of this systematic review, because this therapy is not generally applicable to cases with multiple missing teeth.

To the knowledge of the authors, narrative literature reviews [47] and consensus meetings [810] have been published on the topic in the literature. There is only one systematic review without numerical meta-analysis [11]. In the latter, Yap and Klineberg addressed studies on dental implants in patients with ectodermal dysplasia (ED) and tooth agenesis but not on the alternative treatments. They found documented implant survival rates of 88.5–97.6 % in ED cases and 90–100 % in tooth agenesis. The authors concluded that implants placed in adolescent patients with ED do not have a significant negative influence on facial growth and that implants in ED patients younger than 18 years have a high risk of failure.

The aim of this study is a systematic review of the literature of treatment of patients with congenitally missing teeth and a meta-analysis in from of weighted means of survival and success data. The aim is to elucidate the role of dental implants in the group of patients with congenitally missing teeth in comparison with the other treatment options. In addition to the general treatment outcome parameters, the aim was also to include patient-centered and patient-reported outcome parameters. This paper was prepared as the basis of a consensus meeting of the German Implant Association to be held on 9th–10th of September 2015 in Aerzen, Germany.

Methods

This systematic review was structured and performed according to the preferred reporting items of the PRISMA statement [12].

Focused question

The focused question serving for literature search was structured according to the PICO format (Table 1) “In patients with congenitally missing teeth, does an early occlusal rehabilitation with dental implants in comparison to tooth autotransplants, conventional prosthetics on teeth or preservation of deciduous teeth have better general outcomes in terms of survival, success and better patient centered outcomes in terms of quality of life, self-esteem, satisfaction, chewing function?”.
Table 1

Logical deduction of the literature search phrase from the PICO questionable

Patients

Intervention

Control

Outcomes

Patients with congenitally missing teeth

Rehabilitation

Tooth autotransplants

General:

Dental implants

Preservation of deciduous teeth

Implant/tooth survival/success

Bone augmentation

Conventional prosthodontic treatment

Prosthesis survival/success

Orthodontic treatment

Craniofacial growth

Patient reported:

Quality of life

Self-esteem

Satisfaction

Chewing function

Synonyms, search terms, search phrase

• Anodontia (MeSH)

• Rehabilitation

• Autotransplan*

• Survival

• Hypodontia

• Dental implan* (MeSH)

• Crown (MeSH)

• Success

• Oligodontia

• Alveolar bone grafting (MeSH)

• Dentur* (MeSH)

• Growth

• Tooth aplasia

• Bone augmentation

• Dental Prosthe* (MeSH)

• Quality of life (MeSH)

• Tooth agenesis

 

• Orthodonti* (MeSH)

• Satisfaction

• Congenitally missing teeth

 

• Tooth deciduous (MeSH)

• Self-esteem

• Developmentally absent teeth

  

• Chewing

• Birth defects

  

• Masticat* (MeSH)

• Noncarious defects

  

• Masticat* (MeSH)

• Ectodermal dysplasia

   

AND (tooth OR teeth OR dental)

   

Boolean operators: (Within column OR, columns AND except intervention and control OR) AND (tooth OR teeth OR dental)

NOT cancer, ophthalm*, brain, cataract

Filter: humans

Search phrase

(tooth OR teeth OR dental) AND ((anodontia OR aplas* OR agenesis OR oligodontia OR hypodontia OR developmentally absent OR congenitally missing OR noncarious OR birth defect OR ectodermal dysplasia) AND ((rehabilitation OR dental implant* OR bone augment* OR alveolar bone grafting) OR (autotransplan* OR crown OR denture* OR dental prosth* OR orthodont* OR deciduous )) AND (survival OR success OR growth OR quality of life OR satisfaction OR self-esteem OR chewing OR masticat*) NOT cancer NOT ophthalm* NOT brain NOT cataract))

Search strategy

PubMed of the US National Library of Medicine and EMBASE were used as electronic databases to perform a systematic search for relevant articles published in the dental literature between 1980 up to 31 May 2015.

A first probatory screening using only the MeSH terms “anodontia” and “dental implants” yielded too few results. It became clear that there are numerous synonyms of anodontia, which had to be included in the search (Table 1). A search strategy based on the elements of the PICO question was constructed: (tooth OR teeth OR dental) AND ((anodontia OR aplas* OR agenesis OR oligodontia OR hypodontia OR developmentally absent OR congenitally missing OR noncarious OR birth defect OR ectodermal dysplasia) AND ((rehabilitation OR dental implant* OR bone augment* OR alveolar bone grafting) OR (autotransplan* OR crown OR denture* OR dental prosth* OR orthodont* OR deciduous )) AND (survival OR success OR growth OR quality of life OR satisfaction OR self-esteem OR chewing OR masticat*) NOT cancer NOT ophthalm* NOT brain NOT cataract)).

Screening was performed independently by the two authors. Disagreement regarding inclusion during the first and second stage of study selection was resolved by discussion.

Electronic search was complemented by an iterative hand-search in the reference lists of the already identified articles. If required, the corresponding authors were contacted and requested to provide missing data or information by email.

Study inclusion and exclusion criteria

During the first stage of study selection, the titles and abstracts were screened and evaluated according to the following inclusion criteria:
  1. (1)

    English language.

     
  2. (2)

    Retrospective and prospective clinical trials, observational studies, cross sectional studies, cohort studies, case series.

     
During this procedure, the pre-selected publications were evaluated according to the following exclusion criteria:
  1. (1)

    Inclusion of minimum 5 patients (exclusion of case reports).

     
  2. (2)

    Inadequate case definition or missing follow-up times.

     
  3. (3)

    Double publication of the same sample

     
  4. (4)

    Lack of clinical data

     
  5. (5)

    Studies in cleft lip and palate patients

     

Quality and risk of bias assessment of selected studies

A quality assessment of all selected full-text articles was performed. It made no sense to use the Cochrane collaborations’ tool for assessing risk of bias for randomized controlled studies since the majority of the included studies were retrospective case series. Instead, a system modified from the US Agency for Healthcare Research and Quality Methods Guide for Comparative Effectiveness Reviews was used, which asked for the sources of possible bias [13]. The criteria were each judged with low, medium, and high risk of bias: case selection bias and confounding, attrition bias (loss of participants), detection bias (reliable measures?), reporting bias (selective or incomplete reporting), followed by a summary of the risk. Exclusion and quality assessment was performed independently by both authors. Disagreements were resolved by discussion.

Data extraction

A data extraction template was generated and based on the treatment types for the general outcome parameters and for the patient-centered outcome parameters. Due to incomplete reporting, old studies, and changing definitions in some papers, the required data on survival and success were often not found directly listed in the publications. In this case, they had to be retrieved from side informations or recalculated from tables. The following rules were applied: survival meant that the unit (implant, tooth, prosthesis) was reported to be present in the oral cavity. Success definition of an implant followed the criteria of Buser and coworkers [14] which are the following: absence of persistent subjective complaints such as pain, foreign body sensation and/or dysesthesia, absence of a peri-implant infection with suppuration, absence of mobility, absence of a continuous radiolucency (severe bone resorption) around the implant. A prosthesis either conventional or implant borne was counted as a success, if there were no complications reported like fracture, soft tissue recessions, or documented treatment needs. A deciduous tooth was counted as a success, if there was no ankylosis and infraocclusion reported. A tooth autotransplant was regarded as a success if there were no reports of ankylosis or severe root resorption, infection, or mobility.

Statistics and data synthesis

For data synthesis, the survival and success data of the individual studies were pooled by the weighted mean method and 95 % confidence intervals were calculated as estimations of variance. A meta-analysis was not possible due to the structure of the underlying survival success data as simple percentages without a measure of variance and without control groups in most studies. The survival/success data were weighted both based on patients and units (either implants/teeth/prostheses). Because the studies showed large differences in follow-up times, these were standardized by calculating annual failure rates by dividing the success and survival data through the follow-up time in years. All spreadsheet calculations and statistics were made with the Microsoft Excel program.

Results

Study selection

A total of 1508 potentially relevant titles and abstracts were found by the electronic search. Twelve titles found additionally by evaluation of reference lists of included articles were added. During first screening, 1020 publications were excluded based on database information. One hundred twenty-eight full-text articles were thoroughly evaluated. A total of 65 papers had to be excluded at this stage because they did not fulfill the inclusion criteria of the present systematic review. Sixty-three articles went into qualitative assessment (Fig. 1). One article had to be excluded or pooled with another because of possible double publication of the same cohort (Grecchi (b) [15]), one article because of missing follow-up times (Hvaring [16]), one because of missing clinical data (Kjaer [17]), and two articles because of missing numerical data (Dellavia [18, 19]). The study of Bergendal [20] could be kept in the analysis after contacting the author for clarification (no follow-up time reported). The implants in that study were observed only over the healing period (estimated 6 months in average). Because of too few studies and incompletely reported data studies on orthodontic gap closure, facial growth and masticatory performance were not included into the quantitative data synthesis. Forty-two studies were included in the assessment of general outcome parameter survival and success. For 16 studies on patient-centered variables, also weighted means were calculated.
Fig. 1

Flow diagram of literature search and inclusion

Evaluation of study quality and risk of bias

The majority (n = 25) of the 42 studies were retrospective, 14 were prospective including one RCT 2 were cross sectional studies, and 1 remained unclear. Despite a low evidence level in terms of study design, there were no major concerns about risk of bias. The 30/42 studies were rated with a low risk of bias, and 12/42 had a medium risk. No study had a high risk of bias and consequently no further study was excluded at this stage because of bias (Table 2).
Table 2

Summary of the selected studies and quality assessement

Author

Year

Study type

Case selection bias (homogeneity and confounders)

Performance bias (fidelity to protocol)

Attrition bias (loss of participants)

Detection bias (reliable measures)

Reporting bias (selective reporting or conflicting interests)

Summary assessments

Risk of bias

Implant studies

        

 Ledermann [40]

1993

Retrospect

M

M

L

M

H

M

 Kearns [41]

1999

ProspObs

L

L

L

L

M

L

 Thilander [3]

2001

ProspObs

L

L

L

L

L

L

 Guckes [42]

2002

ProspObs

M

L

L

L

M

L

 Sweeney [43]

2005

Retrospect

L

L

L

L

M

L

 Finnema [27]

2005

Retrospect

L

L

M

L

M

L

 Poggio [44]

2005

Retrospect

M

M

M

M

M

M

 Zarone [45]

2006

ProspObs

L

L

L

L

L

L

 Becelli [46]

2007

Retrospect

L

L

L

L

M

L

 Bergendal [20]

2008

Survey

M

L

H

M

M

M

 Dueled [26]

2008

Retrospect

M

L

M

L

L

L

 Krieger [25]

2009

Retrospect

M

L

L

M

M

L

 Degidi [47]

2009

RCT

L

L

L

L

L

L

 Creton [1]

2010

Retrospect

L

L

M

L

M

L

 Grecchi [15](a), [22](b)

2010

Retrospect

H

M

M

L

L

M

 Nissan [48]

2011

Unclear

H

L

M

M

M

M

 Heuberer [38]

2012

Retrospect

L

L

L

L

M

L

 Hosseini [49]

2013

ProspObs

L

L

L

L

L

L

 Zou [50]

2014

Retrospect

M

L

L

L

L

L

Autotransplants

       

14/19 L 5/19 M

 Kristersson [51]

1991

Retrospect

M

L

L

L

L

L

 Kugelberg [52]

1994

ProspObs

M

L

L

L

L

L

 Marcusson [53]

1996

ProspObs

M

L

L

L

L

L

 Josefsson [54]

1999

Retrospect

M

L

M

L

L

L

 Czochrowska [55]

2002

Retrospect

H

L

M

L

L

M

 Bauss [23]

2004

prospCT

M

L

M

M

M

M

 Jonsson [56]

2004

ProspObs

M

L

L

L

M

L

 Tanaka [57]

2007

Retrospect

M

L

M

L

M

M

 Mensink [58]

2010

Retrospect

M

L

L

L

M

L

 Kvint [59]

2010

Retrospect

M

L

L

L

L

L

 Bokelund [24]

2013

Retrospect

L

L

L

L

L

L

 Deciduous teeth

       

8/11 L 3/11 M

 Bjerklin [60]

2000

ProspObs

M

L

M

L

L

L

 Ith-Hansen [61]

2000

ProspObs

L

L

L

L

L

L

 Sletten [62]

2003

Retrospect

L

L

M

L

M

L

 Bjerklin [63]

2008

ProspObs

M

L

M

L

L

L

 Kjaer [17]

2008

Retrospect

L

L

M

L

L

L

 Hvaring [16]

2013

Cross section

L

L

L

L

L

L

Convent. Prosth.

       

2/6 L 4/6 M

 Hobkirk [64]

1989

Retrospect

H

M

M

L

M

M

 Pröbster [65]

1997

Retrospect

M

L

M

L

M

M

 Garnett [66]

2005

Retrospect

M

L

M

L

M

M

 Dueled [26]

2008

Retrospect

M

L

M

L

L

L

 Krieger [25]

2009

Retrospect

M

L

L

M

M

M

 Spinas [67]

2013

ProspObs

L

L

L

L

M

L

        

2/6 L 4/6 M

Total

n = 42

25 retrosp 14 prosp

     

30/42 L12/42 M

Studies on general outcome parameters

Studies on dental implants and implant-supported prosthetics

A total of 19 studies with a mean follow-up time of 4.6 years (maximum 15.1 years) was included (Table 3). Most studies were of retrospective character. The heterogeneity of the studies concerning survival and success data was low and acceptable for the numerical data synthesis. The studies showed some heterogeneity in patient inclusion, because in some studies, missing single teeth and treatments with single crowns on implants were mixed with severe oligodontia and varying prosthetic treatment including overdentures on implants. Also, management of bone defects and necessity of bone grafting were heterogenous between the studies. This heterogeneity did not lead to exclusion from the present numerical evaluation. The study of Bergendal and coworkers [20] was considered important, because a high ratio of implant failures was reported in childhood. It was one of the very few studies in the literature on implantation in childhood. However, no follow-up time was reported because it was a cross-sectional survey. The author was contacted via email and confirmed that all implant losses had occurred during healing time before prosthetic restoration. Since healing time was has usually a maximum of 6 months, the follow-up time was set on arbitrary 0.6 year. The study of Durstberger et al. [21] had to be excluded because of vague follow-up data and no information of implant losses during follow-up and most of the mentioned patients were only planned for implant placement but had no implants placed. The studies of Grecchi (a) [22] were pooled with Grecchi (b) [15] for numerical analysis, because of assumed double publication of the same samples. In most of the studies, implants had been placed in conjunction with bone grafting, but only Grecchi (a) [22] had presented outcome data on this aspect. There were no prominent differences for implants placed in grafted bone compared with non-grafted sites. Secondary infraocclusion of approximately 1 mm was a problem of implant placements in the maxillary incisor region in childhood [3]. Marginal bone resorption at implants was not a prominent finding and ranged from 0.2 to 1.2 mm in the studies which reported this aspect. The success/survival data and further subgroup analysis for implant survival data is presented below.
Table 3

Synopsis of included studies on dental implants and prosthetics on dental implants in order of publication year

Author

Year

Study type

Population

Treatment

Comparison

Patients

Implants

Implant survival [%]

Implant success [%]

Prosthes. survival [%]

Marginal resorpt.[mm]

Infra occlusion [mm]

Follow-up [y]

Risk of bias

Ledermann [40]

1993

Retrospect

Agenesis, trauma

FPD

9–18 years

34

42

90

90

100

  

3

M

Kearns [41]

1999

ProspObs

ED 5–17 years

Full denture

All

6

41

97.6

    

7.8

L

     

<6 years

2

9

100

44.4

0

  

7.8

 
     

>12 years

4

32

96.9

96.9

100

  

7.8

 

Thilander [3]

2001

ProspObs

Agen,<18 years trauma

SC, FPD

All

18

47

100

100

93.9

  

10

L

     

Incisors

12

26

100

100

88.2

0.75

0.98

10

 
     

Canines

4

8

100

100

100

0.6

0

10

 
     

Premolars

5

13

100

100

100

0.5

0.1–0.6

10

 

Guckes [42]

2002

ProspObs

ED 5–18 years

Full denture

All

51

264

90

    

2

L

     

Maxilla

 

21

71

    

2

 
     

Mandible

 

243

91

    

2

 
     

<11 years

 

46

85

    

2

 
     

11–18 years

 

122

87

    

2

 
     

>18 years

 

96

95

    

2

 

Sweeney [43]

2005

Retrospect

ED adolesc.

FPD, full denture

All

14

61

88.5

 

94

  

3.33

L

     

Maxilla

4

15

80

    

3.33

 
     

Mandible

14

46

91.3

    

3.33

 

Finnema [27]

2005

Retrospect

Oligodont. adults

FPD

All

13

87

89.7

    

3

L

     

Maxilla

  

86

    

3

 
     

Mandible

  

96

    

3

 

Poggio [44]

2005

Retrospect

Oligodont. adults

SC

No

24

46

100

 

82.6

  

5.25

M

Zarone [45]

2006

ProspObs

Ag incisors adults

SC

No

30

34

97.1

94.1

 

1.2

 

3.75

L

Becelli [46]

2007

Retrospect

Oligodont. adults

SC, FPD

No

8

60

96.6

    

8.5

L

Bergendal [20]

2008

Survey

ED, adoles children

n.s.

All

26

47

76.6

    

0.6

M

     

14–15 years

21

33

93.9

    

0.6

 
     

<13 years

5

14

35.7

    

0.6

 

Dueled [26]

2008

Retrospect

Oligodont

SC, FPD

Implant supported

110

179

100

87.3

99

  

3.8

L

Krieger [25]

2009

Retrospect

Oligodont. adults

SC, FPD

All impl

17

40

92.5

 

87.9

  

15.1

L

     

SCImpl

12

24

87.5

62

83.3

  

15.1

 
     

FDP Impl

6

16

100

100

100

  

15.1

 

Degidi [47]

2009

RCT

Ag Incisors adults

SC

All

60

60

100

98.3

100

  

3

L

     

Imm. load

30

30

100

100

100

0.85

 

3

 
     

Conv. load

30

30

100

96.6

93.3

0.75

 

3

 

Creton [1]

2010

Retrospect

Oligodont. adults

FPD

No

44

214

89.8

    

2.9

L

Grecchi (a) [15]

2010

Retrospect

ED adults

FPD

All

4

44

100

90.9

 

0.4

 

1.8

M

     

Grafted

3

 

100

  

0.3

   
     

Non-graft

1

 

100

  

1.2

   
     

Maxilla

 

20

100

  

0.2

   
     

Mandible

 

24

100

  

0.7

   

Grecchi (b) [22]

2010

Retrospect

ED adults

FPD

No

8

78

98.7

  

0.5–0.6

 

1.8

Pooled

Nissan [48]

2011

Unclear

Agenesis

SC

No

12

21

95.2

95.2

   

2.5

M

Heuberer [38]

2012

Retrospect

Mixed ED < 12 years

Full denture

All

6

16

93.8

 

100

  

4

L

     

Maxilla, onplants

4

8

87.5

 

100

  

5

 
     

Mandible

3

8

100

 

100

  

3

 

Hosseini [49]

2013

ProspObs

Hypodontia

SC

No

59

98

100

99

97.2

  

3

L

Zou [50]

2014

Retrospect

ED Adults

FPD

No

25

169

98.3

97.2

100

1.4

 

5

L

Studies on tooth autotransplantation

A total of 11 studies with a mean follow-up time of 7.6 years (maximum 26.4 years) were included, all of which qualified also for the numerical analysis (Table 4). The study heterogeneity concerning survival and success data was low and acceptable for numerical data analysis. The studies showed some heterogeneity in patient inclusion, because in most studies a tooth agenesis sample was mixed also with missing teeth due to trauma and other reasons, which did not lead to exclusion from the present evaluation. According to the table, three studies found a better survival between 10 and 46 % of immature teeth compared to mature teeth. The Bauss study [23] demonstrated better pulpal and periodontal conditions if a transplantated tooth was not moved orthodontically, in comparison of the different orthodontic treatments derotation was more harmful than extrusion. According to the Bokelund study [24], premolar transplants performed better than molars. A preceding primary tooth at the receptor site of a tooth autotransplant was connected with a lower transplant success than a normal primary tooth. The numerical success/survival data are presented below.
Table 4

Synopsis of included studies on tooth autotransplantation in order of publication year

Author

Year

Study type

Population

Comparison

Patients

Transplants

Transplant survival [%]

Transplant success [%]

Pulp vitality [%]

Intact periodont. [%]

Follow-up [y]

Risk of bias

Kristersson [51]

1991

Retrosp.

Agen, incis, trauma

All

50

50

98

82

  

7.5

L

    

Immature

 

41

 

90

  

7.5

 
    

Mature

 

9

 

44

  

7.5

 

Kugelberg [52]

1994

Prosp.Ob

Ag, Tr

All

40

45

96

89

  

4

L

    

Immature

 

23

 

96

100

96

4

 
    

Mature

 

22

 

82

0

82

4

 

Marcusson [53]

1996

Prosp.Ob

Ag, missing

No

29

31

87

   

8

L

Josefsson [54]

1999

Retrosp.

Oligodontia

All

80

110

91

   

4

L

    

Immature

 

11

 

92

  

4

 
    

Mature

 

99

 

82

  

4

 

Czochrowska [55]

2002

Retrosp.

Agenesis

No

28

33

90

79

  

26.4

M

Bauss [23]

2004

Retrosp.

Ag, missing

All

88

91

100

84.6

  

4

M

    

OrthDerot

27

28

100

 

71.4

67.8

4

 
    

OrthExtru

20

21

100

 

90.5

85.7

4

 
    

NoOrthod

41

42

100

 

97.6

95.2

4

 

Jonsson [56]

2004

Prosp.Ob

Ag, missing

No

32

40

92.5

 

76

100

10

L

Tanaka [57]

2007

Retrosp.

Ag, missing

No

24

28

100

 

60.7

 

4

M

Mensink [58]

2010

Retrosp.

Ag, missing

No

44

63

100

 

89

 

1

L

Kvint [59]

2010

Retrosp.

Ag, missing

No

215

215

88.4

81

  

4.8

L

Bokelund [24]

2013

Retrosp.

Agenesis

All

157

211

100

   

10

L

    

Premolar

 

162

 

93

 

93

10

 
    

Molars

 

49

 

60

 

60

10

 
    

NormalPrim

 

71

 

95

 

95

10

 
    

InfraoccPrim

 

140

 

87

 

87

10

 

Studies on preservation of deciduous teeth

A total of 6 studies with a mean follow-up time of 12.5 years (maximum 16.5 years) was included, of which only 4 qualified for the numerical analysis (Table 5). The studies were homogenous in terms of outcome parameters and inclusion of only tooth agenesis patients. Two studies (Kjaer [17], Hvaring [16] ) contained no data on follow-up times. The Kjaer study made an important statement that in patients in whom the dentitions shows morphological signs of ectodermal dysplasia (screw driver shaper incisors, taurodontism, invaginations of incisors or slim incisors, typical ED sites of aplasia), the risk of root resorption fatal prognosis of a deciduous tooth was elevated by the factor 1.46 compared to patients with normal tooth appearance. In general, root resorption, ankylosis, and consecutive infraocclusion were a problem of preservation of deciduous second molars at the site of a secondary premolar aplasia. The absence of root resorption was interpreted as success criterion in most studies, therefore, in contrast to high survival figures, the success of deciduous teeth was lower. The numerical success/survival data are presented below.
Table 5

Synopsis of included studies on preservation of deciduous teeth in order of publication year

Author

Year

Study type

Population

Comparison

Patients

Deciduous teeth

Deciduous tooth survival [%]

No Infra-occlusion (success) [%]

No root resorption [%]

Odds ratio

Follow-up [y]

Risk of bias

Bjerklin [60]

2000

ProspObs

Agenes

no

41

59

88

45

40

 

9

L

Ith-Hansen [61]

2000

ProspObs

Agenes

no

18

26

89.6

88.4

88.4

 

16.5

L

Sletten [62]

2003

Retrospect

Agenes

No

20

28

86

   

12.4

L

Bjerklin [63]

2008

ProspObs

Agenes

No

99

149

91

48

16.7

 

12.2

L

Kjaer [17]

2008

Retrospect

Agenes

ED shaped versus normal

105

n.s.

   

1.46

No

L

Hvaring [16]

2013

Cross section

Agenes

No

111

188

 

57.4

66.6

 

No

L

Studies on conventional prosthetics on teeth

A total of 6 studies with a mean follow-up time of 7.2 years (maximum 15.1 years) was included, all of which qualified for the numerical analysis (Table 6). This relatively small group of studies showed a high level of heterogeneity in patient inclusion, because this group comprised various indications from single missing incisors up to severe hypodontia treated with overdentures on teeth. Nevertheless, it was decided to keep these results in the numerical analysis, because of relatively consistent success and survival data across the different prosthetic therapies. The numerical success/survival data are presented below.
Table 6

Synopsis of included studies on conventional prosthetics on teeth in order of publication year

Author

Year

Study type

Population

Treatment

Comparison

Patients

Teeth

Prostheses

Prosthesis survival [%]

Prosthesis success [%]

Follow-up [y]

Risk of bias

Hobkirk [64]

1989

Retrospect

Hypodontia

Overdenture

All

138

 

138

51.5

 

6

M

     

Mandible

48

 

48

33

 

6

 
     

Maxilla

90

 

90

61

 

6

 

Pröbster [65]

1997

Retrospect

HypodTrauma

Single crown

No

264

392

325

60

 

10

M

Garnett [66]

2005

Retrospect

Hypodontia

Single incis crown

 

45

73

73

59

 

6

M

Dueled [26]

2008

Retrospect

Oligodont adults

SC, FPD

On teeth

19

 

30

89.5

80

3.8

L

    

SC, FPD

On implants

110

 

179

99

91

3.8

 

Krieger [25]

2009

Retrospect

Hypodontia

All

On teeth

5

 

25

85.7

42

15.1

M

    

Single Cr.

On teeth

5

 

5

80

80

15.1

 
    

FDP

On teeth

10

 

20

84.1

72.8

15.1

 
    

All

On implants

17

 

33

87.9

53

15.1

 
    

SC

On implants

12

 

24

83.3

62.5

15.1

 
    

FDP

On implants

6

 

9

100

66.7

15.1

 

Spinas [67]

2013

Prosp.Obs.

Hypodontia

Resin bridge single Incis

 

30

32

32

93.8

 

5

L

Data synthesis

Comparison of the four treatments

The results of the weighted mean method and annual failure rates are presented in Table 7. In addition, the results are visualized in Figs. 2, 3, 4, 5, 6, 7, 8, and 9.
Table 7

Numerical results of general outcome parameters (weighted mean values)

[%]

Survival patient weighted

95 % confid. interval

Success patient weighted

95 % confid. interval

Survival impl/tooth/unit weighted

95 % confid. interval

Success impl/tooth/unit weighted

95 % confid. interval

Annual failure rate survival patient weighted

95 % confid. interval

Annual failure rate success patient weighted

95 % confid. interval

annual failure rate survival impl/tooth/unit weighted

95 % confid. interval

Annual failure rate success impl/tooth/unit weighted

95 % confid. interval

Treatment comparisons

 Implants

95.3

1.9

92.7

4.6

94.1

1.8

95.6

4.1

3.317

0.196

0.815

0.055

3.280

0.150

1.987

0.159

 AutoTX

94.4

4.1

82.5

11.7

94.8

4.0

85.0

4.0

1.061

0.112

1.832

0.638

1.167

0.100

2.334

0.184

 Deciduous

89.6

19.1

51.8

12.6

89.7

19.8

51.7

13.1

0.908

0.157

2.928

1.472

0.903

0.161

4.333

1.494

 ConvProsth

60.2

9.4

59.4

44.3

62.6

7.6

59.4

44.3

5.144

0.851

5.368

4.947

11.098

1.477

9.863

6.895

Implant subgroup analysis

 Children

72.4

18.8

44.4

n.a.

80.1

17.6

44.4

n.a.

50.177

32.083

7.128

n.a.

25.532

9.836

7.128

n.a.

 Adolescents

93.0

9.5

93.7

27.0

82.0

8.3

95.7

7.5

4.610

1.029

2.052

1.313

4.626

0.712

1.262

0.724

 Adults

97.4

4.0

92.2

7.5

95.6

3.3

91.4

6.8

0.670

0.001

1.850

0.272

1.280

0.122

2.188

0.276

 Ectod.Dyspl.

89.6

8.4

93.4

30.3

    

11.665

2.520

1.431

0.219

    

 Hypo/oligodo

97.2

3.9

92.4

5.4

    

0.864

0.067

1.899

0.199

    

 Prosthesis on implants

97.8

2.3

94.5

2.4

    

0.864

0.032

0.884

0.029

    

 Prosthesis on teeth

61.4

7.9

77.9

19.2

62.1

7.7

77.4

20.6

5.060

0.726

3.666

1.695

12.111

1.496

3.046

1.650

 Sing. crowns

98.5

24.5

              

 FPD

96.3

7.7

              

 Full dentures

90.6

9.0

              

 Maxilla

    

84.2

8.3

          

 Mandible

    

91.9

30.3

          

 Single aplas

99.1

14.5

              

 Mild hypodo

94.6

5.3

              

 Severe Oligo

93.1

11.0

              
Fig. 2

The diagram shows survival and success data of implants, tooth autotransplants, preserved deciduous teeth, and conventional prostheses on teeth. The means of the underlying studies are displayed either weighed on patients’ base (=PatWeigSurv, PatWeigSucc) or on units’ base (implant, tooth, or prosthesis) (=UnitWeigSurv, UnitWeigSucc)

Fig. 3

The diagram shows annual failure rates of the four treatments (implants, tooth autotransplants, preserved deciduous teeth, and conventional prostheses on teeth). The data are differentiated as in Fig. 2, either weighed on patients’ base (=PAnFailSurv, PAnFailSucc) or on units’ base (implant, tooth, or prosthesis) (=UnAnFaiSurv, UnAnnFaiSucc)

Fig. 4

The diagram shows the same data types as Fig. 2, however here differentiated according to three age groups, children <13 years, adolescents <18 years, and adults >18 years

Fig. 5

Only slight differences in implant prognosis were observed between studies with syndromic (ED) and non-syndromic cases

Fig. 6

Prostheses on implants had a better prognosis than prostheses on teeth

Fig. 7

Compared to the difference between prostheses on implants and teeth (Fig. 6), the type of prosthesis plays a minor role on implant survival

Fig. 8

Implants in the maxilla had a lower prognosis than implants placed in the mandible

Fig. 9

Compared to the difference between prostheses on implants and teeth (Fig. 6), the size of the defect either single missing teeth or mild or severe hypodontia plays a minor role for implant survival

There is a marked difference in survival data if implants, autotransplants, and preservation of deciduous teeth are compared with conventional prosthetics on teeth, which has only a prosthesis survival of 60.2 % (CI 9.4) at a mean follow-up of 8.4 years. If not the patient but implants/teeth or prosthetic units are used to weigh the means, the results do not change markedly (Fig. 2).

Looking upon the success data, both deciduous teeth and autotransplants have markedly lower success than survival, which is mainly due to the high rate of ankyloses and root resorption in both treatment options using the natural teeth (Fig. 2).

Implants have higher annual failure rates than the natural tooth alternatives. This is also an effect of the shorter follow-up times in implants (4.6 years) compared to autotransplants (7.6 years) and deciduous teeth (12.5 years) (Fig. 3).

A direct comparison of implant and conventional prosthetics was made in two retrospective studies of Krieger and coworkers [25] and Dueled and coworkers [26]. In both studies, prostheses on implants had better survival than on teeth. In the Dueled study, the difference of the prosthesis survival rates between implants and teeth was 9.5 % and the success rates differed by 11 % in favor of implants. The respective differences in the Krieger study were a survival difference of 2.2 % and a prosthesis success difference of 11 %. Krieger and coworkers observed also marked differences of >40 % between prosthesis success and survival, as an indicator for prosthetic maintenance and repair needs over a very long follow-up time of 15.1 years.

Subgroup analysis of dental implant treatment

Children versus adolescents versus adults

There is a clearly lower implant survival with 72.4 % (CI 18.8) when dental implants are used in childhood below the age of 13 (Fig. 4). In most included studies, implant losses in children occurred early during the healing phase. Also in adolescents below the age of 18 years with a success of 93.0 % (CI 9.5) dental implants performed slightly lower than in adults with a success of 97.4 % (CI 4.0) (Fig. 3). The annual implant failure rates in children were 50.177 % (CI 32.083), in adolescents 4.610 % (CI 1.029) and in adults 0.670 % (CI 0.001) (Table 7). The mean observation time of the here included studies in children was 4.1 year, in adolescents 4.9 years, and in adults with congenitally missing teeth 6.4 years.

ED versus non-syndromic congenitally missing teeth (oligodontia)

The implant success/survival data of ED patients are slightly lower than of non-syndromic patients (Fig. 5). The difference is more marked looking upon annual failure rates (Table 7), indicating that these losses occurred after short observation times. These losses were observed mainly during healing time in children suffering from ED.

Prosthesis survival on teeth versus implants

The prosthesis survival on teeth is 61.4 % (CI 7.9) after a mean observation time of 7.2 years. On implants, this figure is markedly higher with 97.8 % (CI 2.3) prosthesis survival after a mean observation of 4.6 years (Fig. 6).

Prosthesis type

The survival data of implants restored with single crowns are slightly higher than restored with fixed partial dentures than restore with full dentures (Fig. 7).

Maxilla versus mandible

The mandible shows with 91.9 % (CI 30.3) a better implant prognosis in patients with congenitally missing teeth than the maxilla with 84.2 % (CI 8.3) (Fig. 8).

Size of defect

Patients with single tooth aplasias (99.1 % (CI 14.5)) had better implant survivals than patients with mild hypodontias (94.6 (CI 5.3) and patients with severe hypodontias (93.1 (CI 11.0)) (Fig. 9).

Studies on patient-centered outcome parameters

Studies on quality of life, self-esteem, and patient satisfaction

A total of 16 retrieved studies included numerical assessment data of patient-centered parameters (Table 8). Many studies were cross-sectional studies with description of a baseline situation in hypodontia patiendraw 1ts. The patient inclusion was relatively homogenous between the studies. However, the studies were relatively heterogenous in the outcome parameters and study treatments because implant, conventional prosthetism, autotransplants, and orthodontic gap closure were included in this table. The number of studies in each treatment was in some cases n = 1 making numerical comparisons difficult.
Table 8

Synopsis of included studies on patient centered outcome parameters in order of publication year

Autor

Year

Study type

Population

Treatment

Comparison

Patients

Implants/missing tooth units

Baseline OHIP [scores]

OHIP improvement [scores]

OHIP esthetic [scores]

Rosenberg self-esteem [scores]

Self-esteem improvement [%]

CPQ [scores]

Satisfact [% sample or vas [%]

Risk of bias

Marcusson [53]

1996

Retrospective

Agenesis missing

AutoTX

no

29

31

      

75

M

Robertsson [29]

2000

Cross section

Agen lat inc

Orthod versus bridge

Orthod clos

30

30

      

66.5

L

     

Orthod open

20

20

      

69.5

 

Finnema [27]

2005

Retrospective

Oligodontia

FPD implants

Posttreatment

13

87

    

61

 

80

M

Wong [68]

2006

Cross section

Oligodontia

n.r.

No

25

93

     

29

 

M

Stanford [69]

2008

Cross section

ED

FPD implants

Posttreatment

109

624

      

91

M

Dueled [26]

2008

Retrospective

Oligodont

SC, FPD

All

129

215

13.4

      

M

     

Control

  

8.2

 

14

   

96

 
     

Implants

110

   

41

   

98

 
     

Convent.

19

   

47

   

84

 

Locker [70]

2010

Cross section

Oligodontia

n.r.

No

36

245

     

22.3

  

Laing [71]

2010

Cross section

Oligodontia

n.r.

Oligodontia all

62

      

26.8

 

L

     

Normal control

61

      

28.5

  

Goshima [28]

2010

ProspObs

Hypodontia

Implant SC

No

18

37

35.2

−26.3

     

L

Kohli [72]

2011

Cross section

ED

n.r.

11–14 years

35

n.g.

     

25.1

 

L

     

15–19 years

14

      

35.9

  
     

Self perceived

       

31.6

  
     

By caregivers

       

35.0

  

Meaney [73]

2012

Cross section

ED

n.g.

no

10

n.g.

61

      

L

Hosseini [49]

2013

ProspObs

Hypodontia

Implant SC

No

59

98

16.2

−8.3

     

L

Hashem [37]

2013

Cross section

Oligodontia

n.g.

ED

41

n.g.

62

  

22

   

M

     

Normal control

41

n.g.

31

  

22.3

    

Anweigi (a) [74]

2013

Long Prosp Obs

Hypodontia

Bridges orthod.

FPD completed

40

n.g.

35

−19.5

     

L

     

Orthodontic phase

37

n.g.

32

22

      

Anweigi (b) [75]

2013

Cross section

NonsyndrOligodonti

n.g.

16–18 years

40

n.g.

28

      

L

     

19–34 years

42

n.g.

33.5

       

Zou [50]

2014

Retrospective

ED

Implants

No

25

169

      

91

M

Nevertheless, a numerical evaluation using the weighted mean method of the parameters OHIP49 (Oral Health Impact Profile), CPQ11-14 (Child Perceptions Questionnaire), and patient satisfaction was performed. The results are displayed in Table 9. The mean baseline score of the Oral Health Impact Profile 49 in prosthetically not treated adults was 27.8 (CI 0.9) points of a possible maximum of 196 points (14.1 % of maximum) indicating that the patients were not strongly limited by the disease. The baseline scores of the Children Perceptions Questionnaire 11–14 in untreated children with oligodontia was 26.2 (CI 2.2) of 148 maximum score points (17.7 % of maximum). A mean improvement of 14.9 OHIP points after prosthetic treatment and occlusal rehabilitation was calculated from three reporting studies. The reported improvement with conventional prosthetics was 19.5 points (only one study), with implant prosthetics 12.5 score points (only two studies). Patient satisfaction rates after treatment was 66.5 % (one study) with orthodontic space closure 75 % in autotransplants (one study), 76.6 % with conventional prosthetics (two studies), and 93.4 % with implant prosthetics (3 studies) in hypodontia patients (Table 9).
Table 9

Numerical results of patient-centered outcome parameters (weighted mean values)

OHIP

Baseline OHIP

95 % confid. interval

OHIP improvement general

95 % confid. interval

OHIP improvement implants

95 % confid. interval

OHIP improvement conventional

95 % confid. interval

[Score units]

27.8

0.9

14.9

1.7

12.5

0.2

19.5

n.a.

CPQ

Baseline CPQ

       

[Score units]

26.6

2.2

      

Patient satisfaction

Satisfaction orthod. clos

 

Satisfaction AutoTX

 

Satisfaction conventional

 

Satisfaction implants

 

[%]

66.5

n.a.

75.0

n.a.

76.6

5.2

93.4

19.3

Two assessments of self-esteem were available. Hashem found self-esteem not significantly affected in hypodontia patients compared to normal control patients. Finnema observed an improvement of patients' self-esteem in 61 % of cases after treatment with dental implants (Table 9).

Studies on chewing efficacy

Two studies were retrieved on chewing efficacy data after prosthetic treatment of hypodontia with implants. Both studies used different methods of assessment. In the study of Finnema and coworkers [27], the mandibular function impairment questionnaire (MFIQ) dropped from 2.23 (44.6 % of maximum scoring range of 5) at baseline to 0.31 after occlusal rehabilitation. The study of Goshima and coworkers [28] reported a marked improvement of bite force, masticatory index and functional impairment index, reduced chewing time, and increased occlusal contact area after prosthetic treatment with dental implants (Table 10).
Table 10

Synopsis of studies of chewing performance before and after treatment with dental implants

Autor

Year

Study type

Population

Treatment

Comparison

Patients

Replaced teeth

Bite force [N]

Color change chew.gum [a*]

Chewing time [s]

Occlusal contact area [mm2]

Masticatory index 0–3

MFIQ

Study quality

Finnema [27]

2005

Retrospect.

Oligodontia

Implant FPD

Before treatment

13

156

     

2.23

M

     

After treatment

       

0.31

 

Goshima [28]

2009

ProspObs

Oligodontia

Implant sing. crown

Before treatment

18

37

1087.3

18.8

21.1

34.3

0.3

 

L

     

After treatment

  

1383

23.2

17.9

44.9

0

  

Further studies

Studies on orthodontic treatments in patients with congenitally missing teeth

The literature search according to the applied criteria revealed four relevant studies on orthodontic therapy. Since orthodontic therapy is in most cases a supportive therapy and no competing therapy orthodontics were not included into the numerical evaluation. Robertsson and Mohlin [29] compared directly in a cross-sectional study of 50 patients with missing lateral incisors, orthodontic space closure with orthodontic gap opening, and a bridge. The patients were slightly more satisfied with the esthetics of the space closure. There were slight differences in general patient satisfaction (see there) in favor of the bridge and no differences in any functional parameters. A remarkable finding in two studies of Uribe and coworkers [30] was that after orthodontic opening of a gap of an agenesis of a lateral incisor, the alveolar ridge lost 1.6 mm ridge width and 0.6 mm ridge height, measured retrospectively in stone models of 31 patients. In their second study [31], the same problem was measured with cone beam CT and a shrinkage of the width of the alveolar of 0.9 mm and no height reduction was measured in 11 patients. Dueled [26] observed in severe hypodontia the patients’ root resorption in 36 % of oligodontia cases, who received adjunctive orthodontic therapy, which was not found in patients without orthodontic therapy. According to the authors, possible explanations for this finding may have been narrower and more cortical alveolar ridges in edentulous sites of tooth agenesis patients and different tooth root morphology (taurodontism).

Studies on craniofacial growth

In this group, 3 studies were retrieved according to the search criteria. The two studies of Dellavia and coworkers [18, 19] contained drawings (polar diagrams) but not the underlying numerical data. Their evaluation of facial photographies demonstrated that patients with ectodermal dysplasia had a slightly reduced global facial growth in comparison with normal reference peers, with a delay of about 2 years in mandibular and maxillary peak developments. The cross-sectional study of Johnson and coworkers [32] analyzed lateral cephalograms of 50 ED patients without treatment with dental implants and compared them with 45 ED patients, who had received dental implants. Craniofacial morphology did not differ significantly between implant-treated and non-treated ED patients.

Discussion

This systematic review of the literature made a few noticeable findings. Dental implants and implant-borne prostheses demonstrated high survival and success data with approximately 30 % higher survival/success figures than conventional prostheses on teeth. However, in children implant and prosthesis, success was 20 % lower and success 40 % lower than in adults and adolescents. The factor severity of hypodontia, syndromal versus non-syndromal tooth defects, size and type of the prosthesis, maxilla versus mandible, were in comparison to the age group of minor significance for the implant prognosis. The two other non-prosthetic treatment options using natural teeth, tooth autotransplants, and preservation of the deciduous teeth had survival rates in the range of dental implants but lower success rates due to a considerable incidence of ankylosis, root resorption, and infraocclusion. Also, patient satisfaction rates were higher for dental implants compared to the other treatment options.

According to the present data, dental implants in patients with congenitally missing teeth have an excellent documented prognosis with survival rates of 95.3 % after a mean follow-up of 4.6 years. The prognosis even rises to 97.4 %, if only adults are considered taking into account the higher failure rates in children as discussed below. These figures are well lined with currently published data on implant prognosis in conventional dental implant patients. For example, a 95.5–96.3 % 5-year survival rate has been published in a recent meta-analysis [33].

The pictures changes slightly in favor of autotransplants and preservation of deciduous teeth when annual failure rates are calculated by dividing the survival/success data through the years of observation. Still, conventional prosthetics have the highest annual failure rates with approximately 5 %, 5 times higher than the annual failure rates after tooth autotransplantation and preservation of natural teeth with approximately 1 %. The annual failure rate is first of all the mathematical result of the 2–3 times longer observation time in the included studies on the treatment options using natural teeth. On the other hand, this finding confirms the clinical experience that a once healed autotransplant or a once preserved deciduous tooth has in contrast to prosthetic components causes hardly any maintenance and repair expenditures. The latter problem is even more evident, if in the present data, the annual survival-based failure rate of 5 % for conventional prosthetics is compared with the annual success-based failure rate of conventional prosthetics of 11 %. Survival means that the prosthetic component is still in the oral cavity whereas success can be much lower due to prosthetic complications and treatment needs. Here, the presented 3 % annual failure rate for dental implants ranges in the middle between conventional prosthetics and treatments with natural teeth. Again, this figure is pretty much in line with recent findings on annual failure rates in implants in conventional dental implant patients. A recently published meta-analysis on implants in conjunction with sinus floor augmentations reported an annual failure rate of 3.5 % [34].

The low prognosis of dental implants in children (72.4 %) compared to adolescents (93.0 %) and adults (97.4 %) was not surprising. Also, the systematic review of Yap and Klineberg [11] came to this conclusion. But the large difference of 25 % was remarkable and is clinically relevant. The high annual failure rates of implants in children according to the included studies of 50.2 % compared to 4.6 % in adolescents and 0.7 % in adults with congenitally missing teeth can be alarming. This is in part again an effect of the lower observation times in the included studies (factor 1.5). At this point, also the inclusion of the observation of Bergendal and coworkers [20] has to be discussed, who observed in a survey in Swedish specialist dental clinics an implant loss rate of 6.1 in adolescents and 64.3 % in children under the age of 13. She reported only healing failures of the implants and no long-term problems in children. The data have been included in this systematic review of the literature here, although it is not a true clinical study and the observation time of 6 months is arbitrary and short. The relevance of the observation of Bergendal has already been discussed elsewhere in the literature [35]. The study was also included because the finding fits to other studies in this review. A biological explanation of healing problems of dental implants in young children may be the brittle cortical bone structure and a more active immune system in children compared to adults and adolescents. An international Delphi consensus group, too, did not reach consensus on the use of dental implants in growing children affected by hypodontia [9, 10]. Decision making for dental implants in children and adolescents cannot only be based on survival data. It includes also secondary infraocclusion of restorations on implants which can account for the upper incisor region up to 2.2mm [3]. Less infraocclusion had been observed for teeth in the lower jaw and upper canines [3].

According to the setting of the second consensus conference of the German Implant Association, in this systematic review, special emphasis had to be laid on patient-reported and patient-centered outcomes. In summary, the retrieved studies showed that patients with hypodontia are less disabled than expected, as demonstrated by the moderate OHIP and CPQ scores. For example, according to a study in edentulous wearers of full dentures before implant stabilization, the baseline OHIP score was much higher (54.2) [36], compared to a mean baseline score in the studies included here of 27.8. This observation may be explained by the adaptation of the juvenile hypodontia patients to the situation from early childhood. Patients do not know it differently. This has also an impact on measurements of self-esteem, which according to Hashem and coworkers was not significantly different between hypodontia patients and control patients [37]. Nevertheless, an effect of occlusal rehabilitation was measurable with quality of life data in three available studies on that topic in the present data. Obviously, there is a lack of clinical studies using quality of life data in the field of congenitally missing teeth. Due to heterogeneity and low number of studies, data with patient-reported outcomes in this review have to be interpreted with caution. The same restrictions apply to interpretations of the presented data on the effect of occlusal rehabilitation on masticatory performance in hypodontia patients.

The PICO question asked whether an early occlusal rehabilitation with dental implants in comparison to tooth autotransplants, conventional prosthetics on teeth, or preservation of deciduous teeth has a better outcome. Based on the presented data here, the question can be answered with yes.

However, each treatment has its time. Preservation of deciduous teeth and autotransplantation is an ideal option in children and adolescents, when dental implants have reduced success rates. The latter option can also be used as a temporary solution until completion of growth. As shown here by the OHIP and self-esteem data and facial growth data, patients with severe oligodontia benefit from early occlusal rehabilitation. A practicable way to safe application of implants in children affected by severe oligodontia may be the proposal by Heuberer and coworkers [38], who used with good success onplants in the maxilla placed in the palate behind the teeth to fix an overdenture prosthesis. In this region, less infraocclusion and less interference with transversal palatal growth are expected. Accordingly for the same reasons, implants can be placed in the mandibular canine region. Also, costs play a role in clinical decision-making with tooth autotransplantation being the most cost-effective option [39] along with preservation of primary teeth, which virtually causes no costs. If the costs are manageable, in clinical decision-making, conventional tooth-borne prosthetic solutions should be thoroughly weighted against implants.

Conclusion

In synopsis of general and patient-centered outcomes, implants yielded the best results, however, not in children younger than 13 years. Autotransplants and deciduous teeth had low annual failure rates and are appropriate treatments in children and adolescents at low costs. Conventional prosthetics had lower survival/success rates than the other options. Due to heterogeneity and low number of studies, patientreported outcomes in this review have to be interpreted with caution.

Declarations

Acknowledgements

The authors appreciate the additional information provided during the process from Dr. Birgitta Bergendal, Övertandläkare, Odontologiska Institutionen, Jönköping, Sweden.

Funding information

This study is funded by the German Association of Dental Implantology (Deutsche Gesellschaft für Implantologie im Zahn-, Mund- und Kieferbereich e.V.).

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors’ Affiliations

(1)
Department of Oral and Maxillofacial Surgery, Red Cross Hospital
(2)
Department of Oral and Maxillofacial Surgery, Schleswig-Holstein University Hospital

References

  1. Créton M, Cune M, Verhoeven W, Muradin M, Wismeijer D, Meijer G. Implant treatment in patients with severe hypodontia: a retrospective evaluation. J Oral Maxillofac Surg. 2010;68:530–8.View ArticlePubMedGoogle Scholar
  2. Bergendal B. Oligodontia ectodermal dysplasia—on signs, symptoms, genetics, and outcomes of dental treatment. Swed Dent J Suppl. 2010;205:13–78. 7–8.PubMedGoogle Scholar
  3. Thilander B, Odman J, Lekholm U. Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study. Eur J Orthod. 2001;23:715–31.View ArticlePubMedGoogle Scholar
  4. Pigno MA, Blackman RB, Cronin Jr RJ, Cavazos E. Prosthodontic management of ectodermal dysplasia: a review of the literature. J Prosthet Dent. 1996;76:541–5.View ArticlePubMedGoogle Scholar
  5. Bergendal B. When should we extract deciduous teeth and place implants in young individuals with tooth agenesis? J Oral Rehabil. 2008;35 Suppl 1:55–63.View ArticlePubMedGoogle Scholar
  6. Kramer FJ, Baethge C, Tschernitschek H. Implants in children with ectodermal dysplasia: a case report and literature review. Clin Oral Implants Res. 2007;18:140–6.View ArticlePubMedGoogle Scholar
  7. Aydinbelge M, Gumus HO, Sekerci AE, Demetoğlu U, Etoz OA. Implants in children with hypohidrotic ectodermal dysplasia: an alternative approach to esthetic management: case report and review of the literature. Pediatr Dent. 2013;35:441–6.PubMedGoogle Scholar
  8. Hobkirk JA, Nohl F, Bergendal B, Storhaug K, Richter MK. The management of ectodermal dysplasia and severe hypodontia. International conference statements. J Oral Rehabil. 2006;33:634–7.View ArticlePubMedGoogle Scholar
  9. Klineberg I, Cameron A, Hobkirk J, Bergendal B, Maniere MC, King N, et al. Rehabilitation of children with ectodermal dysplasia. Part 2: an international consensus meeting. Int J Oral Maxillofac Implants. 2013;28:1101–9.View ArticlePubMedGoogle Scholar
  10. Klineberg I, Cameron A, Whittle T, Hobkirk J, Bergendal B, Maniere MC, et al. Rehabilitation of children with ectodermal dysplasia. Part 1: an international Delphi study. Int J Oral Maxillofac Implants. 2013;28:1090–100.View ArticlePubMedGoogle Scholar
  11. Yap AK, Klineberg I. Dental implants in patients with ectodermal dysplasia and tooth agenesis: a critical review of the literature. Int J Prosthodont. 2009;22:268–76.PubMedGoogle Scholar
  12. Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the PRISMA Statement. PLoS Med. 2009;6:e1000097. doi:10.1371/journal.pmed1000097.PubMed CentralView ArticlePubMedGoogle Scholar
  13. Viswanathan M, Ansari MT, Berkman ND, Chang S, Hartling L, McPheeters LM, et al. Assessing the Risk of Bias of Individual Studies in Systematic Reviews of Health Care Interventions. Agency for Healthcare Research and Quality Methods Guide for Comparative Effectiveness Reviews. March 2012. AHRQ Publication No. 12-EHC047-EF. Available at: http://www.effectivehealthcare.ahrq.gov/ehc/products/322/998/MethodsGuideforCERs_Viswanathan_IndividualStudies.pdf.
  14. Buser D, Janner SF, Wittneben JG, Brägger U, Ramseier CA, Salvi GE. 10-year survival and success rates of 511 titanium implants with a sandblasted and acid-etched surface: a retrospective study in 303 partially edentulous patients. Clin Implant Dent Relat Res. 2012;14:839–51.View ArticlePubMedGoogle Scholar
  15. Grecchi F, Zingari F, Bianco R, Zollino I, Casadio C, Carinci F. Implant rehabilitation in grafted and native bone in patients affected by ectodermal dysplasia: evaluation of 78 implants inserted in 8 patients. Implant Dent. 2010;19:400–8.View ArticlePubMedGoogle Scholar
  16. Hvaring CL, Øgaard B, Stenvik A, Birkeland K. The prognosis of retained primary molars without successors: infraocclusion, root resorption and restorations in 111 patients. Eur J Orthod. 2014;36:26–30.View ArticlePubMedGoogle Scholar
  17. Kjaer I, Nielsen MH, Skovgaard LT. Can persistence of primary molars be predicted in subjects with multiple tooth agenesis? Eur J Orthod. 2008;30:249–53.View ArticlePubMedGoogle Scholar
  18. Dellavia C, Catti F, Sforza C, Tommasi DG, Ferrario VF. Craniofacial growth in ectodermal dysplasia. Angle Orthod. 2010;80:733–9.View ArticlePubMedGoogle Scholar
  19. Dellavia C, Catti F, Sforza C, Grandi G, Ferrario VF. Non-invasive longitudinal assessment of facial growth in children and adolescents with hypohidrotic ectodermal dysplasia. Eur J Oral Sci. 2008;116:305–11.View ArticlePubMedGoogle Scholar
  20. Bergendal B, Ekman A, Nilsson P. Implant failure in young children with ectodermal dysplasia: a retrospective evaluation of use and outcome of dental implant treatment in children in Sweden. Int J Oral Maxillofac Implants. 2008;23:520–4.PubMedGoogle Scholar
  21. Durstberger G, Celar A, Watzek G. Implant-surgical and prosthetic rehabilitation of patients with multiple dental aplasia: a clinical report. Int J Oral Maxillofac Implants. 1999;14:417–23.PubMedGoogle Scholar
  22. Grecchi F, Pagliani L, Mancini GE, Zollino I, Carinci F. Implant treatment in grafted and native bone in patients affected by ectodermal dysplasia. J Craniofac Surg. 2010;21(6):1776–80.View ArticlePubMedGoogle Scholar
  23. Bauss O, Engelke W, Fenske C, Schilke R, Schwestka-Polly R. Autotransplantation of immature third molars into edentulous and atrophied jaw sections. Int J Oral Maxillofac Surg. 2004;33:488–96.Google Scholar
  24. Bokelund M, Andreasen JO, Christensen SS, Kjaer I. Autotransplantation of maxillary second premolars to mandibular recipient sites where the primary second molars were impacted, predisposes for complications. Acta Odontol Scand. 2013;71:1464–8.View ArticlePubMedGoogle Scholar
  25. Krieger O, Matuliene G, Hüsler J, Salvi GE, Pjetursson B, Brägger U. Failures and complications in patients with birth defects restored with fixed dental prostheses and single crowns on teeth and/or implants. Clin Oral Implants Res. 2009;20:809–16.View ArticlePubMedGoogle Scholar
  26. Dueled E, Gotfredsen K, Trab Damsgaard M, Hede B. Professional and patient-based evaluation of oral rehabilitation in patients with tooth agenesis. Clin Oral Implants Res. 2009;20:729–36.View ArticlePubMedGoogle Scholar
  27. Finnema KJ, Raghoebar GM, Meijer HJ, Vissink A. Oral rehabilitation with dental implants in oligodontia patients. Int J Prosthodont. 2005;18:203–9.PubMedGoogle Scholar
  28. Goshima K, Lexner MO, Thomsen CE, Miura H, Gotfredsen K, Bakke M. Functional aspects of treatment with implant-supported single crowns: a quality control study in subjects with tooth agenesis. Clin Oral Implants Res. 2010;21:108–14.View ArticlePubMedGoogle Scholar
  29. Robertsson S, Mohlin B. The congenitally missing upper lateral incisor. A retrospective study of orthodontic space closure versus restorative treatment. Eur J Orthod. 2000;22:697–710.View ArticlePubMedGoogle Scholar
  30. Uribe F, Chau V, Padala S, Neace WP, Cutrera A, Nanda R. Alveolar ridge width and height changes after orthodontic space opening in patients congenitally missing maxillary lateral incisors. Eur J Orthod. 2013;35:87–92.View ArticlePubMedGoogle Scholar
  31. Uribe F, Padala S, Allareddy V, Nanda R. Cone-beam computed tomography evaluation of alveolar ridge width and height changes after orthodontic space opening in patients with congenitally missing maxillary lateral incisors. Am J Orthod Dentofacial Orthop. 2013;144:848–59.View ArticlePubMedGoogle Scholar
  32. Johnson EL, Roberts MW, Guckes AD, Bailey LJ, Phillips CL, Wright JT. Analysis of craniofacial development in children with hypohidrotic ectodermal dysplasia. Am J Med Genet. 2002;112:327–34.View ArticlePubMedGoogle Scholar
  33. Wittneben JG, Millen C, Brägger U. Clinical performance of screw- versus cement-retained fixed implant-supported reconstructions—a systematic review. Int J Oral Maxillofac Implants. 2014;29(Suppl):84–98.View ArticlePubMedGoogle Scholar
  34. Pjetursson BE, Tan WC, Zwahlen M, Lang NP. A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation. J Clin Periodontol. 2008;35(Suppl):216–40.View ArticlePubMedGoogle Scholar
  35. Bergendal B. Interpretive and report bias in publications on implants in patients with ectodermal dysplasia. Int J Prosthodont. 2011;24:505–6.PubMedGoogle Scholar
  36. Jabbour Z, Emami E, de Grandmont P, Rompré PH, Feine JS. Is oral health-related quality of life stable following rehabilitation with mandibular two-implant overdentures? Clin Oral Implants Res. 2012;23:1205–9.View ArticlePubMedGoogle Scholar
  37. Hashem A, Kelly A, O'Connell B, O'Sullivan M. Impact of moderate and severe hypodontia and amelogenesis imperfecta on quality of life and self-esteem of adult patients. J Dent. 2013;41:689–94.View ArticlePubMedGoogle Scholar
  38. Heuberer S, Dvorak G, Zauza K, Watzek G. The use of onplants and implants in children with severe oligodontia: a retrospective evaluation. Clin Oral Implants Res. 2012;23:827–31.View ArticlePubMedGoogle Scholar
  39. Antonarakis GS, Prevezanos P, Gavric J, Christou P. Agenesis of maxillary lateral incisor and tooth replacement: cost-effectiveness of different treatment alternatives. Int J Prosthodont. 2014;27:257–63.View ArticlePubMedGoogle Scholar
  40. Ledermann PD, Hassell TM, Hefti AF. Osseointegrated dental implants as alternative therapy to bridge construction or orthodontics in young patients: seven years of clinical experience. Pediatr Dent. 1993;15:327–33.PubMedGoogle Scholar
  41. Kearns G, Sharma A, Perrott D, Schmidt B, Kaban L, Vargervik K. Placement of endosseous implants in children and adolescents with hereditary ectodermal dysplasia. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1999;88:5–10.View ArticlePubMedGoogle Scholar
  42. Guckes AD, Scurria MS, King TS, McCarthy GR, Brahim JS. Prospective clinical trial of dental implants in persons with ectodermal dysplasia. J Prosthet Dent. 2002;88:21–5.View ArticlePubMedGoogle Scholar
  43. Sweeney IP, Ferguson JW, Heggie AA, Lucas JO. Treatment outcomes for adolescent ectodermal dysplasia patients treated with dental implants. Int J Paediatr Dent. 2005;15:241–8.View ArticlePubMedGoogle Scholar
  44. Poggio CE, Salvato M, Salvato A. Multidisciplinary treatment of agenesis in the anterior and posterior areas: a long term retrospective analysis. Prog Orthod. 2005;6:262–9.PubMedGoogle Scholar
  45. Zarone F, Sorrentino R, Vaccaro F, Russo S. Prosthetic treatment of maxillary lateral incisor agenesis with osseointegrated implants: a 24-39-month prospective clinical study. Clin Oral Implants Res. 2006;17:94–101.View ArticlePubMedGoogle Scholar
  46. Becelli R, Morello R, Renzi G, Dominici C. Treatment of oligodontia with endo-osseous fixtures: experience in eight consecutive patients at the end of dental growth. J Craniofac Surg. 2007;18:1327–30.View ArticlePubMedGoogle Scholar
  47. Degidi M, Nardi D, Piattelli A. Immediate versus one-stage restoration of small-diameter implants for a single missing maxillary lateral incisor: a 3-year randomized clinical trial. J Periodontol. 2009;80:1393–8.View ArticlePubMedGoogle Scholar
  48. Nissan J, Mardinger O, Strauss M, Peleg M, Sacco R, Chaushu G. Implant-supported restoration of congenitally missing teeth using cancellous bone block-allografts. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;111:286–91.View ArticlePubMedGoogle Scholar
  49. Hosseini M, Worsaae N, Schiødt M, Gotfredsen K. A 3-year prospective study of implant-supported, single-tooth restorations of all-ceramic and metal-ceramic materials in patients with tooth agenesis. Clin Oral Implants Res. 2013;24:1078–87.View ArticlePubMedGoogle Scholar
  50. Zou D, Wu Y, Wang XD, Huang W, Zhang Z, Zhang Z. A retrospective 3- to 5-year study of the reconstruction of oral function using implant-supported prostheses in patients with hypohidrotic ectodermal dysplasia. J Oral Implantol. 2014;40:571–80.View ArticlePubMedGoogle Scholar
  51. Kristerson L, Lagerström L. Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors. Eur J Orthod. 1991;13:486–92.View ArticlePubMedGoogle Scholar
  52. Kugelberg R, Tegsjö U, Malmgren O. Autotransplantation of 45 teeth to the upper incisor region in adolescents. Swed Dent J. 1994;18:165–72.PubMedGoogle Scholar
  53. Marcusson KAM, Lilja-Karlander EK. Autotransplantation of premolars and molars in patients with tooth aplasia. J Dent. 1996;24:355–8.View ArticlePubMedGoogle Scholar
  54. Josefsson E, Brattström V, Tegsjö U, Valerius-Olsson H. Treatment of lower second premolar agenesis by autotransplantation: four-year evaluation of eighty patients. Acta Odontol Scand. 1999;57:111–5.View ArticlePubMedGoogle Scholar
  55. Czochrowska EM, Stenvik A, Bjercke B, Zachrisson BU. Outcome of tooth transplantation: survival and success rates 17–41 years posttreatment. Am J Orthod Dentofacial Orthop. 2002;121:110–9.View ArticlePubMedGoogle Scholar
  56. Jonsson T, Sigurdsson TJ. Autotransplantation of premolars to premolar sites. A long-term follow-up study of 40 consecutive patients. Am J Orthod Dentofacial Orthop. 2004;125:668–75.View ArticlePubMedGoogle Scholar
  57. Tanaka T, Deguchi T, Kageyama T, Kanomi R, Inoue M, Foong KW. Autotransplantation of 28 premolar donor teeth in 24 orthodontic patients. Angle Orthod. 2008;78:12–9.View ArticlePubMedGoogle Scholar
  58. Mensink G, Merkesteyn R. Autotransplantation of premolars. Brit Dent J. 2010;208:109–11.View ArticlePubMedGoogle Scholar
  59. Kvint S, Lindsten R, Magnusson A, Nilsson P, Bjerklin K. Autotransplantation of teeth in 215 patients. A follow-up study. Angle Orthod. 2010;80:446–51.View ArticlePubMedGoogle Scholar
  60. Bjerklin K, Bennett J. The long-term survival of lower second primary molars in subjects with agenesis of the premolars. Eur J Orthod. 2000;22:245–55.View ArticlePubMedGoogle Scholar
  61. Ith-Hansen K, Kjaer I. Persistence of deciduous molars in subjects with agenesis of the second premolars. Eur J Orthod. 2000;22:239–43.View ArticlePubMedGoogle Scholar
  62. Sletten DW, Smith BM, Southard KA, Casko JS, Southard TE. Retained deciduous mandibular molars in adults: a radiographic study of long-term changes. Am J Orthod Dentofacial Orthop. 2003;124:625–30.View ArticlePubMedGoogle Scholar
  63. Bjerklin K, Al-Najjar M, Kårestedt H, Andrén A. Agenesis of mandibular second premolars with retained primary molars: a longitudinal radiographic study of 99 subjects from 12 years of age to adulthood. Eur J Orthod. 2008;30:254–61.View ArticlePubMedGoogle Scholar
  64. Hobkirk JA, Goodman JR, Reynolds IR. Component failure in removable partial dentures for patients with severe hypodontia. Int J Prosthodont. 1989;2:327–30.PubMedGoogle Scholar
  65. Pröbster B, Henrich GM. 11-year follow-up study of resin-bonded fixed partial dentures. Int J Prosthodont. 1997;10:259–68.PubMedGoogle Scholar
  66. Garnett MJ, Wassell RW, Jepson NJ, Nohl FS. Survival of resin-bonded bridgework provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors. Br Dent J. 2006;21(201):527–34.View ArticleGoogle Scholar
  67. Spinas E, Aresu M, Canargiu F. Prosthetic rehabilitation interventions in adolescents with fixed bridges: a 5-year observational study. Eur J Paediatr Dent. 2013;14:59–62.View ArticlePubMedGoogle Scholar
  68. Wong AT, McMillan AS, McGrath C. Oral health-related quality of life and severe hypodontia. J Oral Rehabil. 2006;33:869–73.View ArticlePubMedGoogle Scholar
  69. Stanford CM, Guckes A, Fete M, Srun S, Richter MK. Perceptions of outcomes of implant therapy in patients with ectodermal dysplasia syndromes. Int J Prosthodont. 2008;21:195–200.PubMedGoogle Scholar
  70. Locker D, Jokovic A, Prakash P, Tompson B. Oral health-related quality of life of children with oligodontia. Int J Paediatr Dent. 2010;20:8–14.View ArticlePubMedGoogle Scholar
  71. Laing E, Cunningham SJ, Jones S, Moles D, Gill D. Psychosocial impact of hypodontia in children. Am J Orthod Dentofacial Orthop. 2010;137:35–41.View ArticlePubMedGoogle Scholar
  72. Kohli R, Levy S, Kummet CM, Dawson DV, Stanford CM. Comparison of perceptions of oral health-related quality of life in adolescents affected with ectodermal dysplasia relative to caregivers. Spec Care Dentist. 2011;31:88–94.PubMed CentralView ArticlePubMedGoogle Scholar
  73. Meaney S, Anweigi L, Ziada H, Allen F. The impact of hypodontia: a qualitative study on the experiences of patients. Eur J Orthod. 2012;34:547–52.View ArticlePubMedGoogle Scholar
  74. Anweigi L, Finbarr Allen P, Ziada H. Impact of resin bonded bridgework on quality of life of patients with hypodontia. J Dent. 2013;41:683–8.View ArticlePubMedGoogle Scholar
  75. Anweigi L, Allen PF, Ziada H. The use of the Oral Health Impact Profile to measure the impact of mild, moderate and severe hypodontia on oral health-related quality of life in young adults. J Oral Rehabil. 2013;40:603–8.Google Scholar

Copyright

© Terheyden and Wüsthoff. 2015

Advertisement