Soft tissue dimensional changes after alveolar ridge preservation using different sealing materials: a systematic review and network meta-analysis

The bone growing concept: A call for a paradigm shift in bone reconstruction

Alveolar bone reconstruction has significantly evolved over the years. The transition from bone transfer techniques to bone regeneration methods aimed to reduce morbidity, increase the available reservoir of bone, and enhance volumetric outcomes. However, current bone regeneration techniques are prolonged and yield suboptimal biological results. This is primarily because the process relies heavily on bone substitutes that lack osteoinductive or osteogenic properties, with the supply of cells and growth factors entirely dependent on endogenous sources. This article calls for a new paradigm shift, proposing a biological approach for more controlled bone growth by the incorporation of exogenous cells and growth factors into a bone-growing process, thereby enhancing biological outcomes over time. Additionally, it presents a biomorphometric clinical algorithm to tailor treatment protocols for various types of bone loss.

3D surface defect map for assessing buccolingual profile of single tooth gaps following alveolar ridge preservation

AIM

A new, non-invasive approach suggests using single intraoral optical scanning to analyze the ridge profile of single-tooth gaps following alveolar ridge preservation in the absence of a baseline scan. This method involves creating a three-dimensional (3D) surface map to identify and assess contour changes and ridge profiles based on the adjacent teeth.

MATERIALS AND METHODS

The present study was designed as a cross-sectional pilot analysis on a convenience sample of patients undergoing alveolar ridge preservation. Intraoral optical scans were taken on 23 patients, capturing data from 30 edentulous sites. The digital models were then imported into an image analysis software for a 3D surface defect map analysis performed by one examiner. This analysis characterized the buccolingual profile of the single tooth gap relative to the adjacent teeth. 10 linear divergence points, spaced 0.5 mm apart in a corona-apical direction, were identified at the midfacial aspect of the sites. Based on these points the sites were plotted and grouped in three different buccolingual profiles (linear, concave, and convex). Clinical parameters including Keratinized mucosa Width (KMW), and soft tissue phenotype with Colorvue biotype probes were also recorded.

RESULTS

Three different buccolingual patterns (linear, convex, and concave) were identified. Seven sites exhibited a linear profile, 10 sites displayed a concave shape, and 13 showed a convex profile. The linear profile had surface discrepancies similar to the neighboring teeth. In contrast, the convex profile revealed mid-buccal discrepancy localized only at the crestal aspect, while the concave had an extended divergence ranging from 1 to 5 mm below the soft tissue margin. Univariate and multiple logistic regression analyses did not reveal any statistically significant variables influencing profilometric analysis; however, when combining phenotype and KMW, thick phenotypes demonstrated a higher proportion of concavity (OR = 4.83) compared to thin ones, suggesting a significant trend. With every 1 mm of increase in KMW, the probability of showing a concavity decreased (p = 0.057).

CONCLUSION

A 3D surface defect map represents a useful tool for objectively quantifying ridge defects and profiles by assessing profilometric and surface differences compared to adjacent dentition using a single intraoral scan. This method also indicates that KMW may play a critical role in preventing concavity defects. The 3D defect map can guide decision-making during soft tissue augmentation procedures by emphasizing the specific location of the defect and providing more detailed insights into its localization. These parameters can enable the tailoring of flap management and soft tissue grafting strategies to address the patient's individual needs.

Investigation of the extent of post-extraction bone contraction and remodeling after 4 months. A prospective pilot study

OBJECTIVES

To investigate the correlation between the serum levels of 25(OH)D and the resorption of the alveolar bone walls and regeneration of the alveolar space after tooth extraction.

METHODS

14 adults in need of extraction of hopeless teeth were enrolled. An intraoral digital impression was performed, and each patient was tested to assess serum vitamin D levels. Subsequently, extraction of teeth and contextual guided bone regeneration was performed using porcine origin graft material and a resorbable collagen membrane to covert the defect. After 4 months, an impression was taken, and the model was scanned using a professional scanner for lab. At the same time, a cone beam computed tomography was performed to plan implant insertion through fully digital computer guided surgery. Bone was collected to perform histological and histomorphometric analysis. Pre and postoperative scans were compared using a specific software to estimate the volumetric changes. Tests were applied to investigate the relationship between the different predictor variables and the outcome variables.

RESULTS

14 patients were divided in 3 groups depending on the serum Vit-D levels, identifying three ranges corresponding to low (lower than 20), medium (between 20 and 30), and optimal vitamin D levels (higher than 30). Volumetric contraction after extraction was observed for all patients, without any significant difference between the groups. Focusing on the post-extraction regeneration, patients belonging to the group with lower levels of Vit-D displayed lower and more disorganized levels of bone. Immunohistochemistry analysis showed that Col1A1 and Osteocalcin had no physiological alteration. Osteopontin could be identified near the external surface of bone tissue granules. Runx2 signals were detected near the margins of bone trabeculae.

CONCLUSIONS

Serum vit-D levels do not appear to influence the extent of post-extraction bone contraction; on the contrary, they seem to influence the post-extraction regeneration.

CLINICAL SIGNIFICANCE

Vit D serum levels may influence the regenerative aspect during post-extraction turn-over. This might suggest controlling and (in case of low levels) recommend Vit D supplement in the patient diet in case of extraction.

Half- and full-grafting alveolar ridge preservation with different sealing materials: A three-arm randomized clinical trial

OBJECTIVE

The objective of this study is to investigate the effect of different alveolar ridge preservation (ARP) approaches on bone resorption and their potential for facilitating implant placement.

MATERIALS AND METHODS

Patients who underwent one or two tooth extractions with a desire for restoration were included in the study. The participants were randomly assigned to one of three groups for ARP. The groups were as follows: (1) Half grafting of bovine bone mineral (DBBM-C) covered with non-resorbable dense polytetrafluoroethylene (dPTFE) membrane (Test 1 group); (2) Half grafting of bovine bone mineral (DBBM-C) covered with collagen membrane (Test 2 group); and (3) Full grafting with collagen membrane (DBBM-C + Collagen membrane) as the Control group. After 6-month healing period, the evaluation encompassed clinical, radiographic, implant-related outcomes, and the factors contributing to hard and soft tissue alterations.

RESULTS

Enrollment in this study comprised 56 patients. At the 6-month follow-up, radiographic analysis in computed beam computed tomography images was conducted for 18, 19, and 19 patients with 18, 20, and 20 tooth sites in Test 1, Test 2, and Control groups, respectively. Additionally, a total of 15, 17, and 17 patients with 15, 18, and 17 implants were evaluated. Based on radiographic analysis, all groups showed limited ridge resorption at 1 mm from crest horizontally (Test 1: 1.29 ± 1.37; Test 2: 1.07 ± 1.07; Control: 1.54 ± 1.33 mm, p = 0.328), while the Control group showed greater radiographic bone height gain in mid-crestal part vertically (Test 1: 0.11 ± 1.02; Test 2: 0.29 ± 0.83; Control: -0.46 ± 0.95 mm, p = 0.032). There were no significant intergroup differences in terms of keratinized mucosal width, bone density, insertion torque, and the need of additional bone graft. However, the use of a dPTFE membrane resulted in a significantly higher vertical mucosal thickness (Test 1: 2.67 ± 0.90; Test 2: 3.89 ± 1.08; Control: 2.41 ± 0.51 mm, p < 0.001).

CONCLUSIONS

The study showed comparable dimensional preservation with limited vertical shrinkage, while thin buccal bone plate, non-molar sites, and large discrepancy between buccal and palatal/lingual height may contribute to greater shrinkage. Thicker mucosa with dPTFE membrane required further investigation for interpretation.

CLINICAL TRIAL REGISTRATION NUMBER

NCT06049823. This clinical trial was not registered prior to participant recruitment and randomization.

The Long-Term Esthetic and Radiographic Outcome of Implants Placed in the Anterior Maxilla after Ridge Preservation, Combining Bovine Xenograft with Collagen Matrix

The objective of the study was to evaluate the long-term esthetic and radiographic results of implants placed in the anterior maxilla after ridge preservation, combining bovine xenograft with collagen matrix. Fifteen patients who required a single tooth extraction because of fracture, root resorption, or extended caries were included in the study. After extraction, all sites were grafted using Deproteinized Bovine Bone Mineral (DBBM) with collagen and covered by a resorbable collagen matrix (CM). Five months after socket grafting, implants were successfully installed. The implant diameter range was between 3.8 and 4.2 mm. All patients were monitored for over 7 years, both clinically and radiographically. Three independent observers evaluated the long-term esthetic outcome, employing the Pink Esthetic Score (PES) technique. Over a period exceeding seven years, a 100% survival rate was observed for all 15 implants, with minimal marginal bone loss. The mean PES was 11.40 (±1.44) at the first assessment and 11.38 (±1.63) at the second assessment. The difference was not statistically significant (p = 0.978), and the scores of PES measurements indicated excellent esthetic results even after seven years. Based on these preliminary results, it seems that placing collagen bovine bone in a fresh extraction socket, covered with a collagen matrix, can preserve the alveolar ridge and provide long-term stable esthetic results.

Post-extraction volumetric analysis of alveolar ridge contour using subepithelial connective tissue graft in esthetic zone: a randomized controlled clinical trial

OBJECTIVES

The aim of this randomized clinical trial was to assess the alveolar ridge contour after soft tissue augmentation using subepithelial connective tissue graft (SCTG) buccal to fresh extraction sockets in patients with thin buccal bone, versus minimally-traumatic extraction followed by spontaneous healing solely.

MATERIALS AND METHODS

Forty non-restorable maxillary teeth in the esthetic zone were randomly assigned into two groups: minimally-traumatic extraction with SCTG (test) and minimally-traumatic extraction followed by spontaneous healing (control). The outcomes assessed included linear volumetric change of buccal soft tissue contour, vertical tissue loss, gingival thickness (GT), and interdental papilla (IDP) height after 6 months.

RESULTS

The SCTG group showed a significant improvement (P < 0.001) in all outcomes after 6 months. The SCTG group showed a statistically significant (P < 0.001) gain in the buccal soft tissue volumetric change compared to the control group. The SCTG group showed a statistically significant increase in GT (P < 0.001) and IDP height (P < 0.05) after 6 months compared to the control group.

CONCLUSIONS

The use of SCTG buccal to extraction sockets in the anterior maxilla might be considered as a predictable approach for preserving the alveolar ridge contour.

CLINICAL RELEVANCE

SCTG buccal to extraction sockets might counteract post-extraction hard and soft tissue alterations in the esthetic zone.

Is alveolar ridge preservation an overtreatment?

The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing.

Methodological quality of network meta-analysis in dentistry: a meta-research

This meta-research aimed to provide an overview of the methodological quality and risk of bias of network meta-analyses (NMA) in dentistry. Searches for NMA of randomized clinical trials with clinical outcomes in dentistry were performed in databases up to January 2022. Two reviewers independently screened titles/abstracts, selected full texts, and extracted the data. The adherence to PRISMA-NMA reporting guideline, the AMSTAR-2 methodological quality tool, and the ROBIS risk of bias tool were assessed in the studies. Correlation between the PRISMA-NMA adherence and the AMSTAR-2 and ROBIS results was also investigated. Sixty-two NMA studies were included and presented varied methodological quality. According to AMSTAR-2, half of the NMA presented moderate quality (n = 32; 51.6%). The adherence to PRISMA-NMA also varied. Only 36 studies (58.1%) prospectively registered the protocol. Other issues lacking of reporting were data related were data related to the NMA geometry and the assessment of results consistency, and the evaluation of risk of bias across the studies. ROBIS assessment showed a high risk of bias mainly for domains 1 (study eligibility criteria) and 2 (identification and selection of studies). Correlation coefficients between the PRISMA-NMA adherence and the AMSTAR-2 and ROBIS results showed moderate correlation (rho < 0.6). Overall, NMA studies in dentistry were of moderate quality and at high risk of bias in several domains, especially study selection. Future reviews should be better planned and conducted and have higher compliance with reporting and quality assessment tools.

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Influence of using collagen on the soft and hard tissue outcomes of immediate dental implant placement: A systematic review and meta-analysis

OBJECTIVE

To compare the effects of bone grafting materials, collagen-infused grafting materials, and no grafting materials on the soft and hard tissue outcomes when an immediate implant is placed.

MATERIALS AND METHODS

In addition to hand searching, electronic searches were performed in Pubmed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL). Only RCTs were included in our review. The Cochrane ROB 2.0 tool was used to assess the risk of bias (ROB). Two subgroups were used to evaluate implant failure rate, buccal bone resorption, soft tissue thickness, and esthetic scores. In the meta-analysis, both the fixed-effects model and the random-effects model were employed.

RESULT

7 RCTs were selected after screening 580 studies, and 205 patients were included in the review, with 279 implants. Two RCTs were at low bias of risk, three were at moderate bias, and two were deemed at high risk of bias. The failure rate (95% CI: 0.17 to 11.84) and soft tissue thickness were not significantly different between collagen with bone grafting materials and without bone grafting materials. On the basis of the failure rate and buccal bone thickness, there was no significant difference between collagen with bone grafting materials and bone grafting materials. While we found collagen with bone grafting materials could have a significant advantage on the buccal bone thickness (MD: -0.43,95% CI -0.72 to -0.41) and esthetic outcome (MD: -1.23,95% CI -1.90 to -0.55).

CONCLUSION

In the statement of immediate implant implantation, the thickness of the buccal bone and esthetic outcomes did significantly benefit from bone grafting materials with collagen inserted in the "jumping gap".