Short implants compared to regular dental implants after bone augmentation in the atrophic posterior mandible: umbrella review and meta-analysis of success outcomes

Sáenz-Ravello, Gustavo; Ossandón-Zúñiga, Benjamín; Muñoz-Meza, Vicente; Mora-Ferraro, Dante; Baeza, Mauricio; Fan, Shengchi; Sagheb, Keyvan; Schiegnitz, Eik; Díaz, Leonardo

doi:10.1186/s40729-023-00476-0

International Journal of Implant Dentistry

Table 4 Summary of findings table

From: Short implants compared to regular dental implants after bone augmentation in the atrophic posterior mandible: umbrella review and meta-analysis of success outcomes

Outcomes	Follow-up/subgroups		Sample size* (studies)	Relative effect (95% CI)	Anticipated absolute effects**		Certainty of the evidence (GRADE)
Outcomes	Follow-up/subgroups		Sample size* (studies)	Relative effect (95% CI)	Risk with regular dental implants and bone augmentation	Risk difference with short dental implants in native bone	Certainty of the evidence (GRADE)
Implant level
Implant failure (before and after loading)	1 year		498 (5 RCTs)	RR 0.33 (0.15 to 0.74)	87 per 1000 implants	29 fewer per 1000 implants	⨁⨁◯◯ Low^a,e
	1 year		498 (5 RCTs)	RR 0.33 (0.15 to 0.74)	Difference: 58 fewer per 1000 implants (74 to 23 fewer)		⨁⨁◯◯ Low^a,e
	3 years		328 (4 RCTs)	RR 0.68 (0.22 to 2.06)	53 per 1000 implants	36 per 1000 implants	⨁◯◯◯ Very low^a,d,e
	3 years		328 (4 RCTs)	RR 0.68 (0.22 to 2.06)	Difference: 17 fewer per 1000 implants (42 fewer to 56 more)		⨁◯◯◯ Very low^a,d,e
	5 years		425 (4 RCTs, 1 NRSI)	RR 1.18 (0.50 to 2.79)	45 per 1009 implants	53 per 1000 implants	⨁◯◯◯ Very low^a,d,e
	5 years		425 (4 RCTs, 1 NRSI)	RR 1.18 (0.50 to 2.79)	Difference: 8 more per 1000 patients (23 fewer to 81 more)		⨁◯◯◯ Very low^a,d,e
	8 years		121 (1 RCT)	RR 1.69 (0.42 to 6.78)	49 per 1000 implants	83 more per 1000 implants	⨁◯◯◯ Very low^a,d,e
	8 years		121 (1 RCT)	RR 1.69 (0.42 to 6.78)	Difference: 34 more per 1000 patients (29 fewer to 284 more)		⨁◯◯◯ Very low^a,d,e
Marginal bone loss (change from baseline)	1 year		209 (4 RCTs, 1 NRSI)	–	The mean MBL ranged from 0.75 to 1.25 mm	MD 0.07 mm lower (0.14 lower to 0.01 higher)	⨁◯◯◯ Very low^a,b,c,e,g
	3 years		142 (4 RCTs)	–	The mean MBL ranged from 1.39 to 1.76 mm	MD 0.32 mm lower (0.44 lower to 0.19 lower)	⨁⨁◯◯ Low^a,f
	5 years	Short dental implant length of 4 to < 6 mm	44 (2 RCTs)	-	The mean MBL ranged from 1.7 to 2.1 mm	MD 0.45 mm lower (0.72 lower to 0.18 lower)	⨁⨁◯◯ Low^a,f
	5 years	Short dental implant length of 6 to 8.5 mm	119 (2 RCTs, 1 NRSI)	–	The mean MBL ranged from 1.61 to 2.34 mm	MD 0.84 mm lower (1.07 lower to 0.61 lower)	⨁⨁◯◯ Low^a,f
	8 years	Short dental implant length of 6 to 8.5 mm	47 (1 RCT)	–	The mean MBL was 2.46 mm	MD 0.88 mm lower (1.26 lower to 0.5 lower)	⨁⨁◯◯ Low^a,f
Biological complications (before and after loading)	1 year	Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.48 (0.25 to 0.93)	295 per 1000 implants	142 per 1000 implants	⨁◯◯◯ Very low^a,d,e
		Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.48 (0.25 to 0.93)	Difference: 153 fewer per 1000 implants (221 fewer to 21 fewer)		⨁◯◯◯ Very low^a,d,e
		Short dental implant length of 6 to 8.5 mm	379 (3 RCTs)	RR 0.12 (0.04 to 0.32)	188 per 1000 implants	23 per 1000 implants	⨁⨁⨁◯ Moderate^a
		Short dental implant length of 6 to 8.5 mm	379 (3 RCTs)	RR 0.12 (0.04 to 0.32)	Difference: 165 fewer per 1000 implants (180 fewer to 128 fewer)		⨁⨁⨁◯ Moderate^a
	3 years	Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.66 (0.39 to 1.09)	475 per 1000 implants	314 per 1000 implants	⨁⨁◯◯ Very low^a,d,e
		Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.66 (0.39 to 1.09)	Difference: 161 fewer per 1000 patients (290 fewer to 43 more)		⨁⨁◯◯ Very low^a,d,e
		Short dental implant length of 6 to 8.5 mm	209 (2 RCTs)	RR 0.21 (0.10 to 0.46)	324 per 1000 implants	68 per 1000 implants	⨁⨁⨁◯ Moderate^a
		Short dental implant length of 6 to 8.5 mm	209 (2 RCTs)	RR 0.21 (0.10 to 0.46)	Difference: 256 fewer per 1000 implants (292 fewer to 175 fewer)		⨁⨁⨁◯ Moderate^a
	5 years	Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.77 (0.42 to 1.42)	475 per 1000 implants	366 per 1000 implants	⨁◯◯◯ Very low^a,d,e
		Short dental implant length of 4 to < 6 mm	119 (2 RCTs)	RR 0.77 (0.42 to 1.42)	Difference: 109 fewer per 1000 implants (276 fewer to 200 more)		⨁◯◯◯ Very low^a,d,e
		Short dental implant length of 6 to 8.5 mm	306 (2 RCTs, 1 NRSI)	RR 0.22 (0.12 to 0.40)	346 per 1000 implants	76 per 1000 implants	⨁⨁⨁◯ Moderate^a
		Short dental implant length of 6 to 8.5 mm	306 (2 RCTs, 1 NRSI)	RR 0.22 (0.12 to 0.40)	Difference: 270 fewer per 1000 implants (304 fewer to 208 fewer)		⨁⨁⨁◯ Moderate^a
	8 years	Short dental implant length of 6 to 8.5 mm	121 (1 RCT)	RR 0.34 (0.17 to 0.66)	443 per 1000 implants	151 per 1000 implants	⨁⨁⨁◯ Moderate^a
	8 years	Short dental implant length of 6 to 8.5 mm	121 (1 RCT)	RR 0.34 (0.17 to 0.66)	Difference: 292 fewer per 1000 implants (367 fewer to 150 fewer)		⨁⨁⨁◯ Moderate^a
Prosthetic level
Prosthesis failures and complications	3 years		154 (4 RCTs)	RR 0.65 (0.23 to 1.84)	117 per 1000 implants	76 per 1000 implants	⨁◯◯◯ Very low^a,d,e
	3 years		154 (4 RCTs)	RR 0.65 (0.23 to 1.84)	Difference: 41 fewer per 1000 patients (90 fewer to 98 more)		⨁◯◯◯ Very low^a,d,e
	5 years		176 (4 RCTs, 1 NRSI)	RR 0.91 (0.45 to 1.84)	161 per 1000 implants	147 per 1000 implants	⨁◯◯◯ Very low^a,d,e
	5 years		176 (4 RCTs, 1 NRSI)	RR 0.91 (0.45 to 1.84)	Difference: 14 fewer per 1000 patients (89 fewer to 135 more)		⨁◯◯◯ Very low^a,d,e
	8 years		48 (1 RCT)	RR 1.23 (0.31 to 4.90)	130 per 1000 implants	160 per 1000 implants	⨁◯◯◯ Very low^a,d,e
	8 years		48 (1 RCT)	RR 1.23 (0.31 to 4.90)	Difference: 30 more per 1000 patients (90 fewer to 509 more)		⨁◯◯◯ Very low^a,d,e
Patient satisfaction
Patient’s treatment preference side (split-mouth)	1-month post-loading		40 (1 RCT)	One month after delivery of the definitive prostheses, an independent assessor asked the patients which treatment they preferred. All 20 patients treated with mandibular implants preferred short implants side vs conventional length implants placed in augmented bone side (p < 0.0001)			⨁⨁◯◯ Low^a,e
Cost-effectiveness	There is no data regarding the costs, or other economic evaluation that assess the focused question of the present umbrella review

Patient or population: atrophic mandible
Setting: private dental clinic—Italy
Intervention: short dental implants in native bone
Comparison: regular dental implants and bone augmentation
GRADE Working Group grades of evidence—high certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect
CI confidence interval, MD mean difference, NRSI non-randomized study of intervention, RCT randomized controlled trial, RR risk ratio
Explanations
Risk of bias: ^aHigh risk of bias studies largely contribute to the weighted overall estimate of effect due to the lack of blinding of participants, surgeons and evaluators. We decided to downgrade only one level, as we recognized the impossibility to blind the intervention and comparison (evident differences between implant lengths). In addition, we did not downgrade due to the lack of sample size calculations (high risk of other bias), as we could perform a post-hoc power analysis for the meta-analysis using TSA
Inconsistency: ^bSensitivity analysis: the source of heterogeneity may be due to the differences of the risk of bias between Pieri 2017 (moderate risk of bias) and the other RCTs (high risk of bias). We decided to downgrade one level because of this. ^cThere is a statistically significant moderate to high heterogeneity (assessed with I² and p value). Therefore, we decided to downgrade one level
Indirectness: we do not have serious concerns regarding the indirect evidence or clinical diversity of the included studies (PICO)
Imprecision: ^dWide confidence intervals that include “no effect” and appreciable benefits and harms (RR less than 0.75 or over 1.25). Therefore, we decided to downgrade two levels. ^eThe available number of events does not allow to reach the calculated Optimal Information Size. Therefore, we decided to downgrade one level. ^fAlthough the OIS is reached by power calculations, and in consequence, is sufficient to detect statistically significant differences, we decided to downgrade one level because there is not a minimal important difference reported in the literature that allows an adequate clinical difference estimate. ^gWide confidence intervals that include “no effect” and appreciable benefits and harms (minimal clinical difference set to “MD different from zero”). Therefore, we decided to downgrade one level
Publication bias: we do not have serious concerns regarding the publication bias (funnel plot observation)
*Participants or implants
**The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI)

Back to article page