Horizontal augmentation techniques in the mandible: a systematic review

Purpose

Placement of dental implants has evolved to be an advantageous treatment option for rehabilitation of the fully or partially edentulous mandible. In case of extensive horizontal bone resorption, the bone volume needs to be augmented prior to or during implant placement in order to obtain dental rehabilitation and maximize implant survival and success.

Methods

Our aim was to systematically review the available data on lateral augmentation techniques in the horizontally compromised mandible considering all grafting protocols using xenogeneic, synthetic, or allogeneic material. A computerized and manual literature search was performed for clinical studies (published January 1995 to March 2021).

Results

Eight studies ultimately met the inclusion criteria comprising a total of 276 procedures of xenogeneic, allogeneic, or autogenous bone graft applications in horizontal ridge defects. Particulate materials as well as bone blocks were used as grafts with a mean follow-up of 26.0 months across all included studies. Outcome measures, approaches and materials varied from study to study. A gain of horizontal bone width of the mandible with a mean of 4.8 mm was observed in seven of eight studies. All but one study, reported low bone graft failure rates of 4.4% in average.

Conclusions

Only limited data are available on the impact of different horizontal augmentation strategies in the mandible. The results show outcomes for xenogeneic as well as autologous bone materials for horizontal ridge augmentation of the lower jaw. The use of allogeneic bone-block grafts in combination with resorbable barrier membranes must be re-evaluated. Randomized controlled clinical trials are largely missing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-022-00421-7.

Group 1 ITI Consensus Report: The influence of implant length and design and medications on clinical and patient-reported outcomes

OBJECTIVES

The aim of Working Group 1 was to address the influence of different local (implant length, diameter, and design) and systemic (medications) factors on clinical, radiographic, and patient-reported outcomes in implant dentistry. Focused questions on (a) short posterior dental implants (≤6 mm), (b) narrow diameter implants, (c) implant design (tapered compared to a non-tapered implant design), and (d) medication-related dental implant failures were addressed.

MATERIALS AND METHODS

Four systematic reviews were prepared in advance of the Consensus Conference and were discussed among the participants of Group 1. Consensus statements, clinical recommendations, and recommendations for future research were based on structured group discussions until consensus was reached among the entire expert Group 1. The statements were then presented and accepted following further discussion and modifications as required by the plenary.

RESULTS

Short implants (≤6 mm) revealed a survival rate ranging from 86.7% to 100%, whereas standard implant survival rate ranged from 95% to 100% with a follow-up from 1 to 5 years. Short implants demonstrated a higher variability and a higher Risk Ratio [RR: 1.24 (95% CI: 0.63, 2.44, p = 0.54)] for failure compared to standard implants. Narrow diameter implants (NDI) have been classified into three categories: Category 1: Implants with a diameter of <2.5 mm ("Mini-implants"); Category 2: Implants with a diameter of 2.5 mm to <3.3 mm; Category 3: Implants with a diameter of 3.3 mm to 3.5 mm. Mean survival rates were 94.7 ± 5%, 97.3 ± 5% and 97.7 ± 2.3% for category 1, 2 and 3. Tapered versus non-tapered implants demonstrated only insignificant differences regarding clinical, radiographic, and patient-reported outcomes. The intake of certain selective serotonin reuptake inhibitors and proton pump inhibitors is associated with a statistically significant increased implant failure rate. The intake of bisphosphonates related to the treatment of osteoporosis was not associated with an increased implant failure rate.

CONCLUSIONS

It is concluded that short implants (≤6 mm) are a valid option in situations of reduced bone height to avoid possible morbidity associated with augmentation procedures; however, they reveal a higher variability and lower predictability in survival rates. Narrow diameter implants with diameters of 2.5 mm and more demonstrated no difference in implant survival rates compared to standard diameter implants. In contrast, it is concluded that narrow diameter implants with diameters of less than 2.5 mm exhibited lower survival rates compared to standard diameter implants. It is further concluded that there are no differences between tapered versus non-tapered dental implants. Certain medications such as selective serotonin reuptake inhibitors and proton pump inhibitors showed an association with a higher implant failure rate.

In vivo assessment of bone healing following Piezotome® ultrasonic instrumentation

PURPOSE

This pilot study evaluated the molecular, histologic, and radiographic healing of bone to instrumentation with piezoelectric or high speed rotary (R) devices over a 3-week healing period.

MATERIAL AND METHODS

Fourteen Sprague-Dawley rats (Charles River Laboratories International, Inc., Wilmington, MA, USA) underwent bilateral tibial osteotomies prepared in a randomized split-leg design using Piezotome® (P1) (Satelec Acteon, Merignac, France), Piezotome 2® (P2) (Satelec Acteon), High-speed R instrumentation, or sham surgery (S). At 1 week, an osteogenesis array was used to evaluate differences in gene expression while quantitative analysis assessed percentage bone fill (PBF) and bone mineral density (BMD) in the defect, peripheral, and distant regions at 3 weeks. Qualitative histologic evaluation of healing osteotomies was also performed at 3 weeks.

RESULTS

At 1 week, expression of 11 and 18 genes involved in bone healing was significantly (p < .05) lower following P1 and P2 instrumentation, respectively, relative to S whereas 16 and 4 genes were lower relative to R. No differences in PBF or BMD were detected between groups within the osteotomy defect. However, significant differences in PBF (p = .020) and BMD (p = .008) were noted along the peripheral region between P2 and R groups, being R the group with the lowest values. Histologically, smooth osteotomy margins were present following instrumentation using P1 or P2 relative to R.

CONCLUSIONS

Piezoelectric instrumentation favors preservation of bone adjacent to osteotomies while variations in gene expression suggest differences in healing rates due to surgical modality. Bone instrumented by piezoelectric surgery appears less detrimental to bone healing than high-speed R device.

Flapless surgery and its effect on dental implant outcomes

PURPOSE

The aim of this article was to review the current literature with regard to the efficacy and effectiveness of flapless surgery for endosseous dental implants. The available data were evaluated for short- and long-term outcomes.

MATERIALS AND METHODS

A MEDLINE search was conducted on studies published between 1966 and 2008. For the purpose of this review, only clinical (human) studies with five or more subjects were included, and clinical opinion papers were excluded. Clinical studies or reports were further rated in terms of the level or weight of evidence using criteria defined by the Oxford Center for Evidence-Based Medicine in 2001.

RESULTS

The available data on flapless technique indicate high implant survival overall. The prospective cohort studies demonstrated approximately 98.6% (95% CI: 97.6 to 99.6) survival, suggesting clinical efficacy, while the retrospective studies or case series demonstrated 95.9% (95% CI: 94.8 to 97.0) survival, suggesting effective treatment. Six studies reported mean radiographic alveolar bone loss ranging from 0.7 to 2.6 mm after 1 year of implant placement. Intraoperative complications were reported in four studies, and these included perforation of the buccal or lingual bony plate. Overall, the incidence of intraoperative complications was 3.8% of reported surgical procedures.

CONCLUSION

Flapless surgery appears to be a plausible treatment modality for implant placement, demonstrating both efficacy and clinical effectiveness. However, these data are derived from short-term studies with a mean interval of 19 months, and a successful outcome with this technique is dependent on advanced imaging, clinical training, and surgical judgment.

Risk factors for endosseous dental implant failure

Failures of endosseous dental implants are rare and tend to cluster in patients with common profiles or risk factors. Clinical trials indicate that factors related to implant devices, anatomy, occlusion,systemic health or exposures, microbial biofilm, host immuno-inflammatory responses, and genetics may increase the risk for im-plant complications or loss. In general, factors associated with the patient appear more critical in determining risk for implant failure than those associated with the implant itself. Several risk factors can be modified. For example, the patient can modify smoking and the clinician can modify implant selection, site preparation,and loading strategy. In identifying these factors and making appropriate interventions, clinicians can enhance success rates while improving oral function, esthetics, and patient well-being.

The effects of periodontal therapy on vascular endothelial function: a pilot trial

BACKGROUND

Chronic periodontal infection is associated with an increased risk of coronary heart disease. Although the mechanism responsible for the relationship between periodontal disease and cardiovascular events is not fully understood, it is hypothesized that the chronic inflammatory burden of periodontal disease may lead to impaired functioning of the vascular endothelium.

METHODS

Twenty-two otherwise healthy adults with moderate to severe periodontitis who underwent complete mouth disinfection were evaluated to determine if periodontal therapy would result in improved endothelial function and a decrease in serum inflammatory markers. Subjects had measurements of periodontal disease severity, flow-mediated (endothelium-dependent), and nitroglycerin-mediated (endothelium-independent) dilation of the brachial artery, serum C-reactive protein (CRP) and interleukin 6 (IL-6), and serum total and high-density lipoprotein cholesterol levels on 2 baseline visits separated by 1 month and, again, 1 month after treatment.

RESULTS

There were no significant changes in clinical periodontal measures, flow-mediated dilation, nitroglycerin-mediated dilation, CRP, IL-6, total cholesterol, or high-density lipoprotein cholesterol between the repeated baseline measurements. Periodontal treatment, however, resulted in significant improvements in periodontal pocketing, flow-mediated dilation, and serum IL-6, as well as a trend toward reduction in serum CRP; there were no significant changes in nitroglycerin-mediated dilation or in cholesterol levels.

CONCLUSIONS

These results represent proof of concept that improvement in endothelial function, as measured by flow-mediated dilation of the brachial artery, may be possible through near-elimination of chronic oral infection and suggest that the conduct of a larger controlled trial is justified.

Porphyromonas gingivalis bacteremia induces coronary and aortic atherosclerosis in normocholesterolemic and hypercholesterolemic pigs

OBJECTIVES

The aim of this study was to determine whether recurrent intravenous injections with Porphyromonas gingivalis (P gingivalis), mimicking periodontitis-associated bacteremia, promotes coronary artery and aortic atherosclerosis in pigs.

METHODS AND RESULTS

Pigs (n=36) fed low- or high-fat chow were divided into P gingivalis-sensitized and P gingivalis-challenged groups or P gingivalis-sensitized controls and saline-treated controls. Pigs were sensitized with 10(9) killed P gingivalis subcutaneously. Four weeks later all sensitized pigs in the group to be challenged started intravenous injections thrice weekly for 5 months with 10(6) to 10(7) colony forming units of P gingivalis while controls received saline. Anti-P gingivalis antibody, serum cholesterol, and complete blood counts were assayed monthly. Pigs were euthanized 2 weeks after the last injection, and coronary arteries and aortas were analyzed by histomorphometry and immunohistochemistry. Anti-P gingivalis antibody was increased by P gingivalis exposure. P gingivalis-challenged pigs developed a significantly greater amount of coronary and aortic atherosclerosis than controls in the normocholesterolemic group and nearly significant in the hypercholesterolemic group. P gingivalis was detected by polymerase chain reaction in arteries from most (94%, 16 of 17) P gingivalis-challenged pigs but not controls.

CONCLUSIONS

Recurrent P gingivalis bacteremia induces aortic and coronary lesions consistent with atherosclerosis in normocholesterolemic pigs and increases aortic and coronary atherosclerosis in hypercholesterolemic pigs.