Comparison of dermal matrix and polytetrafluoroethylene membrane for socket bone augmentation: a clinical and histologic study

Microbial colonization in the partially exposed nonabsorbable membrane during alveolar ridge preservation

AIM

This study evaluated the impact of the partial exposition of the nonabsorbable membrane (dPTFE) on microbial colonization during bone healing.

MATERIALS AND METHODS

Patients indicated for tooth extraction were randomized to dPTFE group (n = 22) - tooth extraction and alveolar ridge preservation (ARP) using an intentionally exposed dPTFE membrane and USH group (n = 22) - tooth extraction and unassisted socket healing. Biofilm samples were collected at the barrier in the dPTFE and on the natural healing site in the USH after 3 and 28 days. Samples from the inner surface of the dPTFE barrier were also collected (n = 13). The microbiome was evaluated using the Illumina MiSeq system.

RESULTS

Beta diversity was different from 3 to 28 days in both groups, and at 28 days, different microbial communities were identified between therapies. The dPTFE was characterized by a higher prevalence and abundance of gram-negative and anaerobic species than USH. Furthermore, the inner surface of the dPTFE membrane was colonized by a different community than the one observed on the outer surface.

CONCLUSION

Intentionally exposed dPTFE membrane modulates microbial colonization in the ARP site, creating a more homogeneous and anaerobic community on the inner and outer surfaces of the membrane.

CLINICAL RELEVANCE

DPTFE promoted faster biofilm colonization and enrichment of gram-negative and anaerobes close to the regenerated site in the membrane's inner and outer surfaces. dPTFE membrane can be used exposed to the oral site, but approaches for biofilm control should still be considered. The study was retrospectively registered at Clinicaltrials.gov (NCT04329351).

Postextraction ridge preservation by using dense PTFE membranes: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The use of dense polytetrafluoroethylene (dPTFE) membranes in alveolar ridge preservation may help reduce the risk of bacterial contamination and infection, maintaining the soft-tissue anatomy. However, systematic reviews on their efficacy in postextraction sites are lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the efficacy of alveolar ridge preservation with dPTFE membranes when used alone or in combination with bone grafting materials in postextraction sites.

MATERIAL AND METHODS

An electronic search up to February 2021 was conducted by using PubMed, Embase, and the Cochrane library to detect studies using dPTFE membranes in postextraction sites. An additional manual search was performed in relevant journals. Clinical and radiographic dimensional changes of the alveolar ridge, histomorphometric, microcomputed tomography, implant-related findings, and rate of complications were recorded. One-dimensional meta-analysis was performed to calculate the overall means and 95% confidence intervals (α=.05).

RESULTS

A total of 23 studies, 14 randomized controlled trials, 4 retrospective cohort studies, 3 case series, and 2 prospective nonrandomized clinical trials, met the inclusion criteria. Five studies were included in the quantitative analysis. The meta-analysis revealed that the use of dPTFE membranes resulted in a statistically significant (P=.042) increase in clinical keratinized tissue of 3.49 mm (95% confidence interval [CI]: 0.16, 6.83) when compared with extraction alone. Metaregression showed that the difference of 1.10 mm (95% CI: -0.14, 2.35) in the radiographic horizontal measurements was not significant (P=.082), but the difference of 1.06 mm (95% CI: 0.51, 1.62) in the radiographic vertical dimensional change between dPTFE membranes+allograft and extraction alone was statistically significant (P<.001).

CONCLUSIONS

The use of dPTFE membranes was better than extraction alone in terms of keratinized tissue width and radiographic vertical bone loss.

Efficacy of alveolar ridge preservation with xenografts and resorbable socket sealing materials in the esthetic region: A systematic review with meta-analyses

AIM

The present systematic review aimed to identify and summarize the clinical, radiographic, and histological outcomes of alveolar ridge preservation using bone xenografts and absorbable sealing materials compared with spontaneous healing in the esthetic zone.

MATERIALS AND METHODS

Randomized clinical trials (RCTs) fulfilling specific eligibility criteria were included. Two review authors independently searched for eligible studies, extracted data from the published reports and performed the risk of bias assessment (RoB 2 tool). Study results were summarized using random effects meta-analyses.

RESULTS

Thirteen articles concerning 10 RCTs were included, involving a total of 357 participants. Most of studies were considered as "low" risk of bias. Meta-analyses indicated less horizontal (difference in means-MD = 1.88 mm; p < 0.001), vertical mid-buccal (MD = 1.84 mm; p < 0.001) and vertical mid-lingual (MD = 2.27 mm; p < 0.001) bone resorption in alveolar ridge preservation compared to spontaneous healing as assessed clinically. Bone changes assessed radiographically showed consistent results in terms of horizontal (at 1 mm: MD = 1.84 mm, p < 0.001), vertical mid-buccal (MD = 0.95 mm; p < 0.001) and mid-lingual (MD = 0.62 mm; p = 0.05) resorption. Part of the bone resorption in the spontaneous healing group was compensated by soft-tissues, since the observed differences between groups in linear ridge reduction evaluated through cast models superimposition were smaller (MD = 0.52 mm; p < 0.001).

CONCLUSIONS

Alveolar ridge preservation with xenogeneic bone substitutes and non-autogenous resorbable socket sealing materials is efficacious in reducing post-extraction bone and ridge changes in the esthetic region.

Alveolar ridge preservation: Complications and cost-effectiveness

Alveolar ridge preservation is routinely indicated in clinical practice with the purpose of attenuating postextraction ridge atrophy. Over the past two decades numerous clinical studies and reviews on this topic have populated the literature. In recent years the focus has primarily been on analyzing efficacy outcomes pertaining to postextraction dimensional changes, whereas other relevant facets of alveolar ridge preservation therapy have remained unexplored. With this premise, we carried out a comprehensive evidence-based assessment of the complications associated with different modalities of alveolar ridge preservation and modeled the cost-effectiveness of different therapeutic modalities as a function of changes in ridge width and height. We conclude that, among allogeneic and xenogeneic bone graft materials, increased expenditure does not translate into increased effectiveness of alveolar ridge preservation therapy. On the other hand, a significant association between expenditure on a barrier membrane and reduced horizontal and vertical ridge resorption was observed, though only to a certain degree, beyond which the return on investment was significantly diminished.

Influence of partially exposed nonabsorbable membrane for alveolar ridge preservation: A randomized controlled trial

AIM

This randomized controlled trial evaluated the impact of a partially exposed non-absorbable membrane (dPTFE) in Alveolar Ridge Preservation (ARP) procedures on clinical, tomographic, immunoenzymatic, implant-related, and patient-centered outcomes.

MATERIALS AND METHODS

Patients with a hopeless maxillary single-rooted tooth demanding rehabilitation with implants were included. Patients were randomized into two groups: dPTFE (n = 22)-tooth extraction followed by ARP using a partially exposed dPTFE membrane; USH (n = 22)-unassisted socket healing. Clinical and tomographic analyses were performed at baseline and after 3 months. After 3 months, patients received one dental implant. Implant stability quotient was obtained following implant placement. Bone-related markers were analyzed in bone biopsies using an immunoenzymatic assay.

RESULTS

Greater gain in Keratinized Mucosa Width (KMW) was observed in the dPTFE (1.33 ± 0.98 mm) compared to USH (0.59 ± 0.98 mm) (Mann-Whitney test, Z = 2,28, p < 0.05). USH showed a reduction of pain/discomfort, edema, and interference with daily life from the seventh day (Friedman/Wilcoxon test, maxT = 7.48, 8.00, and 5.92, respectively, p < 0.05). dPTFE presents a reduction of edema and interference with daily life from the 7th day and pain/discomfort from the 14th day (Friedman/Wilcoxon test, maxT = 5.40, 5.26, and 4.78, respectively, p < 0.05). The dPTFE group presented higher pain/discomfort in the 35 and 42 days and higher edema from 7 to 42 days postoperatively than USH group (Mann-Whitney test, p < 0.05). No differences between groups were observed in the tomographic measures, immunoenzymatic analysis, and implant stability (p > 0.05).

CONCLUSION

dPTFE was superior to USH by increasing KMW gain. However, dPTFE without bone graft presented similar bone loss compared to USH. This clinical trial was not registered prior to participant recruitment and randomization (NCT04329351).

Histomorphometry of Bone after Intentionally Exposed Non-Resorbable d-PTFE Membrane or Guided Bone Regeneration for the Treatment of Post-Extractive Alveolar Bone Defects with Implant-Supported Restorations: A Pilot Randomized Controlled Trial

Aim: The aim of the present study was to investigate quantitative histological examination of bone reconstructed with non-resorbable high-density polytetrafluoroethylene membrane (d-PTFE), left intentionally exposed in post extraction sockets grafted with anorganic bone material, and removed after four weeks, versus extraction and guided bone regeneration (GBR), performed two months later. Materials and Methods: This study was designed as a multicenter randomized controlled trial of parallel-group design. Patients were selected and consecutively treated in three centers in Italy. Patients randomly received intentionally exposed non-resorbable d-PTFE membrane (group A), or guided bone regeneration (group B), to treat post-extractive alveolar bone defects with implant-supported restorations. Outcomes were: the implant failure, any mechanical and biological complications, patient satisfaction, and qualitative and histomorphometric evaluation of the collected bone samples. Results: Eighteen patients were consecutively enrolled in the trial. Of these, six out of 18 patients were male. All the included patients were treated according to the allocated interventions, and no drop out occurred. No implant failure and no complications were experienced, and all the patients were fully satisfied with the function and aesthetic of their implant-supported restoration, without difference between groups. Morphological analysis revealed no sign of tissue reaction, such as fibrosis or necrosis. Regenerated bone was well mineralized in both groups, but it seemed more mature in group B than in group A. Three samples showed a minimal number of lymphocytes. Several blood vessels of small size occupied the medullary spaces, where the tissue resulted in more maturity, indicating the activity of the tissue in progress. The histomorphometric evaluation showed no statistically significant differences in the tissue volume fractions between the two groups of patients. Conclusions: With the limitation of the present study, buccal plate reconstruction with an intentionally exposed non-resorbable membrane is an effective and easy procedure for regenerating a resorbed buccal bone plate, reducing the need for guided bone regeneration.

Minimal invasiveness in the alveolar ridge preservation, with or without concomitant implant placement

The aim of this systematic review was to evaluate the benefit of ridge preservation (RP) with minimally invasive (MI) approaches with or without concomitant implant placement on morbidity, esthetics, and patient-related outcomes. Three Internet sources were used to search for appropriate papers. The search strategy was designed to include any clinical study published on RP with MI approaches such as flapless surgery, socket shield and socket sealing techniques and, use of biological agents. Characteristics of the individual studies, regarding methodological aspects, quantitative and qualitative data were extracted. The potential risk of bias was estimated, and the acquired evidence was graded. Independent screening of 860 reports resulted in 26 included original articles. Nine publications evaluated MI approaches for RP without concomitant implant placement. Eleven studies evaluated interventions for RP with immediate implant placement (IIP). Six studies compared RP with IIP vs RP without IIP. This systematic review found that MI approaches in most of the studies failed to improve clinical variables regarding morbidity, esthetics, and patient-related outcomes. Based on the limited number of studies analyzed and the methodological discrepancies observed, it is not possible to confirm that MI approaches promote a significant benefit when applied to RP procedures.

Autogenous tooth bone graft material prepared chairside and its clinical applications: a systematic review

This systematic review was conducted to evaluate the available literature on the clinical outcomes of the use of autogenous tooth bone graft prepared chairside, and its current applications. A literature search was done to answer the focused questions "In partially edentulous patients, what are the alveolar ridge volumetric changes, histological findings, and implant survival rates in sites augmented with autogenous tooth bone graft prepared chairside?" Twenty articles were included at the end of the database search. Reported alveolar bone dimension changes after ridge preservation ranged between - 0.64 mm and + 2.26 mm for height, and between - 1.21 mm and + 0.41 mm for width. Augmented sites showed a significant increase in their dimensions in all investigations. The implant survival rate was 98.8% for delayed placement and 97.4% for immediate placement. Additional reports were found on the percentage bone formation following the use of this graft at different postoperative time points, which showed a higher bone volume with time. Currently available studies have included small samples, with short follow-up periods, and most have lacked a control group. Within the limitations of this review, the available evidence suggests that the autogenous tooth bone graft prepared chairside is as effective as other bone grafting materials.

A three-in-one alveolar process reconstruction protocol for maxillary molar sites with severe residual bone height deficiency: A proof-of-concept pilot study

BACKGROUND

Implant placement in maxillary molar sites with severe height deficiency often requires multiple surgeries, which was time-consuming, invasive, and subject to serious postoperative complications.

PURPOSE

To introduce and assess a three-in-one technique (extraction, alveolar ridge preservation [ARP], and sinus elevation) for augmenting deficiency maxillary molar alveolar ridges.

MATERIAL AND METHODS

Fourteen patients with severe posterior maxillary ridge height deficiency underwent extraction, sinus elevation via an intrasocket window and ARP using sticky bone and then covered with acellular dermal matrix (ADM). Primary closure was intentionally not obtained. Cone-beam computed tomography and periapical radiography were used to measure dimensional ridge changes over time. Bone biopsies were taken at implant placement 7-21 months after surgery, which proceeded without additional grafting. Peri-implant soft tissue was assessed after 8-12 months of functional loading.

RESULTS

Maxillary molar sites (13 first molars, 1 second molar) with a mean sinus floor height of 1.73 ± 0.86 mm and mean buccal plate thickness of 1.62 ± 1.15 mm were elevated and grafted. Immediately after surgery, the mean sinus floor height was 14.03 ± 1.97 mm and the alveolar thickness at virtual implant platform level was 12.99 ± 1.88 mm. After 5-9 months healing, those measurements decreased by 2.45 ± 1.73 mm (p = 0.000) and 3.88 ± 3.95 mm (p = 0.006), respectively. Healed ridges were composed of 18.74% ± 4.34% mean vital bone and 19.08% ± 9.10% mean residual graft. After 8-12 months of functional loading, the peri-implant tissue appeared healthy, and there was a mean marginal bone loss of 0.12 ± 0.11 mm.

CONCLUSIONS

For maxillary first molar sites with severe sinus floor height deficiency, this minimally invasive three-in-one treatment allows for uncomplicated implant placement and short-term functional stability.

In Vivo Biocompatibility Analysis of a Novel Barrier Membrane Based on Bovine Dermis-Derived Collagen for Guided Bone Regeneration (GBR)

Collagen-based barrier membranes are nowadays the prevalent option for Guided Bone Regeneration (GBR) procedures. Xenogeneic collagen is highly biocompatible as it shares a similar structure to native human collagen, which prevents it from eliciting an exaggerated host immune response. Most commercially available collagen barrier membranes are porcine-derived, while bovine-derived alternatives are still rarely available. The aim of the present study was to investigate the tissue responses and the barrier functionality of a novel GBR membrane composed of bovine collagen type I (BM). Therefore, the subcutaneous implantation model in Wistar rats was performed to compare the novel medical device with two already clinically used native porcine-based barrier membranes, i.e., Jason^® membrane (JM) and Bio-Gide^® (BG), at 10-, 30-, 60-, and 90-days post implantationem. Histochemical and immunohistochemical stains were used for histopathological evaluation including a biocompatibility scoring according to the DIN EN ISO 10993-6 norm as well as histomorphometrical analyses of the occurrence of M1 and M2 macrophages and the transmembraneous vascularization. The bovine membrane exhibited a host tissue reaction that was comparable to both control materials, which was verified by the scoring results and the histomorphometrical macrophage measurements. Moreover, the novel membrane exhibited an integration pattern without material fragmentation up to day 60. At day 90, material fragmentation was observable that allowed for “secondary porosity” including transmembrane vascularization. The results of this study suggest that the novel bovine barrier membrane is fully biocompatible and suitable for indications that require GBR as a suitable alternative to porcine-sourced barrier membranes.

Classification Based on Extraction Socket Buccal Bone Morphology and Related Treatment Decision Tree

Background: Alveolar ridge preservation (ARP) can successfully reduce volumetric ridge changes. However, there is still no consensus on what technique is the most advantageous for each specific clinical scenario. Hence, the aim of the present paper was to provide a treatment decision tree to guide the choice of predictable ARP procedures based on extraction socket buccal bone morphology and integrity. Material and Methods: Three socket types (ST) are proposed and discussed based on buccal bone morphology (intact, dehiscence or fenestration). Results: A decision tree for ARP was developed in order to merge ST classification with suitable treatment modalities. In the decision tree, the issue of when to allow unassisted healing or ARP was discussed. Described methods included bone grafting and collagen plug, and absorbable membrane or non-resorbable membrane, with or without flap elevation. Conclusion: A decision tree for ARP procedures was provided to guide clinicians towards the most conservative and predictable treatment approach based on remaining socket anatomical structures after extraction.

Data Mining-Based Clinical Study on the Effect of Oral Restoration Film in Guiding Oral Bone Regeneration and Dental Implantation

Oral repair membrane guided oral bone regeneration, particularly in dental implants, is a guided regeneration technology for bone tissue. The principle is based on the characteristics of rapid migration of epithelial cells and fibroblasts and slower migration of osteoblasts. Materials are placed in the bone defect, creating a relatively closed environment which is conducive to the growth of bone tissue. In this paper, we have evaluated clinical effects of Hai'ao oral repair membrane as a barrier membrane to guide bone regeneration in implants. For this purpose, certain treatment data are collected through data mining and patient's names with bone defects in the implantation area are selected. According to the randomness principles, these patients are divided into experimental and control groups and preoperative examinations along with basic periodontal treatments are performed on the selected cases. Furthermore, we have analyzed different effects by comparing treatment conditions. Experimental results, as a technical shielding film, verify that Hai'ao oral repair membrane meets requirements of safety and no immune rejection. It plays a role in promoting bone formation around the implant. Mid-to-long-term follow-up is satisfactory with no related complications. At the same time, it has the advantages of simple operation, reduced patient suffering, convenient transportation and storage, and longer validity period. Compared with the control group in terms of safety evaluation of postoperative vital signs, laboratory examinations, and incision healing, Hai'ao oral repair membrane has no significant difference. Postoperative osteogenesis effect is equivalent to that of the control group and meets requirements of superiority. Hai'ao oral repair membrane is used as a shielding membrane material in implant surgery technology to guide bone regeneration.

Preservation of Alveolar Ridge using Graft Material after Tooth Extraction: A Clinical Trial

Background:

The alveolar process is a tooth-dependent structure, and hence, removal of teeth results in the alteration of alveolar process. To alter bone remodeling after dental extraction, various techniques have been put forward for ridge preservation.

Aim:

The aim of this study is to evaluate and compare the changes of hard and soft tissues in postextraction socket after the application of bone graft material.

Materials and Methods:

Healthy patients of sample size of 40 were selected who underwent the extraction of anterior tooth irrespective of the arch, from premolar of one side to another, with the exception of incisors in mandible. Twenty patients were randomly selected as the control group and other 20 as the experimental group using an allograft bone material, i.e., beta-tricalcium phosphate to fill the socket. Cone-beam computed tomography (CBCT) was done as baseline preoperative and postoperative at 14 weeks after the extraction. CBCTs data help in recording linear and volumetric measurements which was performed by calibrated examiners to record all the measurements. After measurements, digital planning of dental implants was performed.

Results:

Forty participants were selected, in which 20 patients each were as the experimental and control groups. No significant difference was found at basal line at any of the cases. At follow-up of 14 weeks, statistical significance was seen in buccal and lingual plate height in the experimental group, and no significant difference was seen in the control group.(P = 0.023).

Conclusions:

This study clearly points out that an alveolar ridge preservation technique provides therapeutic benefit by limiting bone resorption in comparison to extraction alone.

Comparison Study of the Histomorphometric Results after Socket Preservation with PRF and Allograft Used for Socket Preservation-Randomized Controlled Trials

The aim of the present clinical study was to assess and compare the histomorphometric results and efficacy of freeze-dried bone allograft (FDBA) in combination with platelet-rich fibrin (PRF), and PRF as a sole grafting material for socket preservation. Ninety patients in need of tooth extraction and implant restoration were included in this study. The participants were randomly divided into three groups based on post-extraction clinical protocol: socket preservation procedure with allograft in combination with a PRF membrane (PRFm), PRF as a sole grafting material, and a control group. A total of 90 implants were placed four months post-extraction. During the surgical re-entry a bone biopsy was harvested with a trephine drill. Histological samples were prepared and analyzed for percentage vital bone and connective tissue. One-way ANOVA with Bonferroni post-hoc analysis were used to assess the results. Both test groups revealed a significantly higher percentage of vital bone formation compared to the control group. No statistically significant differences regarding vital bone formation and connective tissue quantity between the tested groups were observed (FDBA + PRFm: 3.29 ± 13.03%; and PRF: 60.79 ± 9.72%). From a clinical and histological point of view, both materials in the test groups are suitable for the filling of post-extraction sockets without bone defects. Both of the tested groups revealed a significantly higher percentage of vital bone formation compared to the control group.

Regenerating Critical Size Rat Segmental Bone Defects with a Self-Healing Hybrid Nanocomposite Hydrogel: Effect of Bone Condition and BMP-2 Incorporation

The aim of the current study is to assess the biological performance of self-healing hydrogels based on calcium phosphate (CaP) nanoparticles and bisphosphonate (BP) conjugated hyaluronan (HA) in a critical size segmental femoral bone defect model in rats. Additionally, these hydrogels are loaded with bone morphogenetic protein 2 (BMP-2) and their performance is compared in healthy and osteoporotic bone conditions. Treatment groups comprise internal plate fixation and placement of a PTFE tube containing hydrogel (HA_BP -CaP) or hydrogel loaded with BMP-2 in two dosages (HA_BP -CaP-lowBMP2 or HA_BP -CaP-highBMP2). Twelve weeks after bone defect surgery, bone formation is analyzed by X-ray examination, micro-CT analysis, and histomorphometry. The data show that critical size, segmental femoral bone defects cannot be healed with HA_BP -CaP gel alone. Loading of the HA_BP -CaP gel with low dose BMP-2 significantly improve bone formation and resulted in defect bridging in 100% of the defects. Alternatively, high dose BMP-2 loading of the HA_BP -CaP gel does not improve bone formation within the defect area, but leads to excessive bone formation outside the defect area. Bone defect healing is not affected by osteoporotic bone conditions.

Interventions for replacing missing teeth: alveolar ridge preservation techniques for dental implant site development

BACKGROUND

Alveolar bone changes following tooth extraction can compromise prosthodontic rehabilitation. Alveolar ridge preservation (ARP) has been proposed to limit these changes and improve prosthodontic and aesthetic outcomes when implants are used. This is an update of the Cochrane Review first published in 2015.

OBJECTIVES

To assess the clinical effects of various materials and techniques for ARP after tooth extraction compared with extraction alone or other methods of ARP, or both, in patients requiring dental implant placement following healing of extraction sockets.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 19 March 2021), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2021, Issue 2), MEDLINE Ovid (1946 to 19 March 2021), Embase Ovid (1980 to 19 March 2021), Latin American and Caribbean Health Science Information database (1982 to 19 March 2021), Web of Science Conference Proceedings (1990 to 19 March 2021), Scopus (1966 to 19 March 2021), ProQuest Dissertations and Theses (1861 to 19 March 2021), and OpenGrey (to 19 March 2021). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. A number of journals were also handsearched.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) on the use of ARP techniques with at least six months of follow-up. Outcome measures were: changes in the bucco-lingual/palatal width of alveolar ridge, changes in the vertical height of the alveolar ridge, complications, the need for additional augmentation prior to implant placement, aesthetic outcomes, implant failure rates, peri-implant marginal bone level changes, changes in probing depths and clinical attachment levels at teeth adjacent to the extraction site, and complications of future prosthodontic rehabilitation.

DATA COLLECTION AND ANALYSIS

We selected trials, extracted data, and assessed risk of bias in duplicate. Corresponding authors were contacted to obtain missing information. We estimated mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes, with 95% confidence intervals (95% CI). We constructed 'Summary of findings' tables to present the main findings and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 16 RCTs conducted worldwide involving a total of 524 extraction sites in 426 adult participants. We assessed four trials as at overall high risk of bias and the remaining trials at unclear risk of bias. Nine new trials were included in this update with six new trials in the category of comparing ARP to extraction alone and three new trials in the category of comparing different grafting materials. ARP versus extraction: from the seven trials comparing xenografts with extraction alone, there is very low-certainty evidence of a reduction in loss of alveolar ridge width (MD -1.18 mm, 95% CI -1.82 to -0.54; P = 0.0003; 6 studies, 184 participants, 201 extraction sites), and height (MD -1.35 mm, 95% CI -2.00 to -0.70; P < 0.0001; 6 studies, 184 participants, 201 extraction sites) in favour of xenografts, but we found no evidence of a significant difference for the need for additional augmentation (RR 0.68, 95% CI 0.29 to 1.62; P = 0.39; 4 studies, 154 participants, 156 extraction sites; very low-certainty evidence) or in implant failure rate (RR 1.00, 95% CI 0.07 to 14.90; 2 studies, 70 participants/extraction sites; very low-certainty evidence). From the one trial comparing alloplasts versus extraction, there is very low-certainty evidence of a reduction in loss of alveolar ridge height (MD -3.73 mm; 95% CI -4.05 to -3.41; 1 study, 15 participants, 60 extraction sites) in favour of alloplasts. This single trial did not report any other outcomes. Different grafting materials for ARP: three trials (87 participants/extraction sites) compared allograft versus xenograft, two trials (37 participants, 55 extraction sites) compared alloplast versus xenograft, one trial (20 participants/extraction sites) compared alloplast with and without membrane, one trial (18 participants, 36 extraction sites) compared allograft with and without synthetic cell-binding peptide P-15, and one trial (30 participants/extraction sites) compared alloplast with different particle sizes. The evidence was of very low certainty for most comparisons and insufficient to determine whether there are clinically significant differences between different ARP techniques based on changes in alveolar ridge width and height, the need for additional augmentation prior to implant placement, or implant failure. We found no trials which evaluated parameters relating to clinical attachment levels, specific aesthetic or prosthodontic outcomes for any of the comparisons. No serious adverse events were reported with most trials indicating that the procedure was uneventful. Among the complications reported were delayed healing with partial exposure of the buccal plate at suture removal, postoperative pain and swelling, moderate glazing, redness and oedema, membrane exposure and partial loss of grafting material, and fibrous adhesions at the cervical part of previously preserved sockets, for the comparisons xenografts versus extraction, allografts versus xenografts, alloplasts versus xenografts, and alloplasts with and without membrane.

AUTHORS' CONCLUSIONS

ARP techniques may minimise the overall changes in residual ridge height and width six months after extraction but the evidence is very uncertain. There is lack of evidence of any differences in the need for additional augmentation at the time of implant placement, implant failure, aesthetic outcomes, or any other clinical parameters due to lack of information or long-term data. There is no evidence of any clinically significant difference between different grafting materials and barriers used for ARP. Further long-term RCTs that follow CONSORT guidelines (www.consort-statement.org) are necessary.

Socket seal surgery techniques in the esthetic zone: a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials

Background

The socket seal surgery (SSS) technique is a common alternative for the management of the post-extraction sockets that requires a primary closure of the wound to promote proper regeneration and ridge preservation.

Objective

To learn about the effect of different SSS techniques on alveolar ridge preservation

Material and methods

Two independent and calibrated reviewers conducted an electronic search in PubMed, Cochrane, and Web of Science for randomized clinical trials (RCT) published up to June 2020. The evaluation of the risk of bias in the included studies was carried out following the Cochrane manual for interventions of systematic reviews, version 5.1.0. A meta-analysis of ridge width changes at − 1, − 3, and − 5 mm cutoff points from bone crest was conducted using a random-effects model. The risk of types I and II errors against accrued data was appraised obtaining the required information size using a trial sequential analysis package (TSA).

Results

A total of 135 sockets located in the esthetic zone were evaluated with a minimum of a 3-month follow-up after tooth extraction in 6 RCTs. The evaluated SSS techniques were free gingival graft (FGG), collagen matrix (CM), collagen sponge (CS), acellular dermal matrix (ADM), and polytetrafluoroethylene membrane (PTFEm). The FGG in sockets without bone filling showed significant results in preserving both buccal and lingual bone height (− 1.42 mm in the experimental group versus − 0.01 in the control group). The comparison of CM and FGG with bone filling did not show clinical differences in terms of dimensional bone changes. No clinical differences were found in either width or gingival thickness when comparing CM and CS. The meta-analyses of RW changes comparing CM versus FGG showed no significant differences, but a trend for lessening horizontal reduction at − 1, − 3, and − 5 mm in favor of FGG. The TSA showed that accrued data did not reach the required information size, and more evidence is required for clinical significance inferences.

Conclusions

There are several predictable SSS techniques to improve clinical results in ridge preservation. More clinical studies in the form of clinical trials are required to demonstrate the superiority of one technique over another.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-021-00294-2.

Effectiveness of bilayer porous polyethylene membrane for alveolar ridge preservation: A randomized controlled trial

BACKGROUND

Porous polyethylene has been successfully used in several medical applications with good outcomes. Based on this, a new bilayer porous polyethylene membrane (B-PPM) was developed for possibly being used as a membrane in alveolar ridge preservation.

PURPOSE

To evaluate the clinical efficacy of a new B-PPM in comparison to high-density polytetrafluoroethylene membrane (d-PTFE) in alveolar ridge preservation.

MATERIALS AND METHODS

Thirty patients were randomized into two groups according to the membranes used to cover the socket (B-PPM or d-PTFE). Wound healing was monitored at day 1, 3, 7, 14, 28, and 4 months postoperatively. Dimensional changes of alveolar ridge were measured immediately after tooth extraction and at 4 months later using intraoral scanner and cone beam computed tomography. Bone cores were harvested before implant placement. Implant stability at insertion and prior to prosthesis delivery were also measured.

RESULTS

No significant difference in socket wound closure between groups was observed excepting at day 14 that B-PPM showed a faster wound closure than d-PTFE (P = .03). Greater bone resorptions were seen on buccal than lingual side and on coronal than apical part of the alveolar ridge. No significant difference in dimensional changes of alveolar ridge, new bone formation, connective tissue content, residual bone grafts, and implant stability between two groups.

CONCLUSION

B-PPPM was safe and effective for alveolar ridge preservation.

Bone regeneration and graft material resorption in extraction sockets grafted with bioactive silica-calcium phosphate composite (SCPC) versus non-grafted sockets: clinical, radiographic, and histological findings

Purpose

The purpose of the present study was to evaluate the effect of silica-calcium phosphate composite (SCPC) granules on bone regeneration in extraction sockets.

Methods

Ten patients were selected for a split-model study. In each patient, bone healing in SCPC-grafted and control ungrafted sockets was analyzed through clinical, radiographic, histomorphometric, and immunohistochemical assessments 6 months postoperatively.

Results

A radiographic assessment using cone-beam computed tomography showed minimal ridge dimension changes in SCPC-grafted sockets, with 0.39 mm and 1.79 mm decreases in height and width, respectively. Core bone biopsy samples were obtained 6 months post-extraction during implant placement and analyzed. The average percent areas occupied by mature bone, woven bone, and remnant particles in the SCPC-grafted sockets were 41.3%±12%, 20.1%±9.5%, and 5.3%±4.4%, respectively. The percent areas of mature bone and woven bone formed in the control ungrafted sockets at the same time point were 31%±14% and 24.1%±9.4%, respectively. Histochemical and immunohistochemical analyses showed dense mineralized bundles of type I collagen with high osteopontin expression intensity in the grafted sockets. The newly formed bone was well vascularized, with numerous active osteoblasts, Haversian systems, and osteocytes indicating maturation. In contrast, the new bone in the control ungrafted sockets was immature, rich in type III collagen, and had a low osteocyte density.

Conclusions

The resorption of SCPC granules in 6 months was coordinated with better new bone formation than was observed in untreated sockets. SCPC is a resorbable bone graft material that enhances bone formation and maturation through its stimulatory effect on bone cell function.

Trial Registration

ClinicalTrials.gov Identifier: NCT03897010

Advanced platelet-rich fibrin and freeze-dried bone allograft for ridge preservation: A randomized controlled clinical trial

BACKGROUND

Advanced platelet-rich fibrin (A-PRF) is an autogenous blood product with applications in dento-alveolar surgery. However, there is minimal information regarding its optimal clinical application or efficacy. The aim of this multi-arm parallel randomized controlled clinical trial was to evaluate the efficacy of A-PRF alone or with freeze-dried bone allograft (FDBA) in improving vital bone formation and alveolar dimensional stability during ridge preservation.

METHODS

Forty patients requiring extraction of non-molar teeth and replacement with dental implants were randomized into one of four ridge preservation approaches: A-PRF, A-PRF+FDBA, FDBA, or blood clot. A-PRF was prepared at 1,300 rpm for 8 minutes. Non-traumatic extractions and ridge preservation was performed. After an average of 15 weeks healing, bone core samples were harvested at the time of implant placement for micro-CT and histomorphometric analysis. Ridge dimensions were measured immediately after extraction and before implant placement.

RESULTS

Significantly greater loss of ridge height was noted in the blood clot group (3.8 ± 2.0 mm) compared to A-PRF (1.8 ± 2.1 mm) and A-PRF+FDBA (1.0 ± 2.3 mm) groups (P < 0.05). No significant differences in ridge width reduction were noted between groups. Significantly more vital bone was present in the A-PRF group (46% ± 18%) compared to the FDBA group (29% ± 14%) (P < 0.05). Bone mineral density was significantly greater in the FDBA group (551 ± 58 mg/cm³ ) compared to blood clot (487 ± 64 mg/cm³ ) (P < 0.05).

CONCLUSIONS

This study demonstrates A-PRF alone or augmented with FDBA is a suitable biomaterial for ridge preservation. This study represents the first randomized controlled clinical trial comparing A-PRF with and without FDBA to FDBA alone for ridge preservation.

Socket Preservation Using a (Dense) PTFE Barrier with or without Xenograft Material: A Randomized Clinical Trial

When alveolar preservation procedures are not performed after tooth extraction, aesthetic and functional impairment could occur. Guided bone regeneration using polytetrafluoroethylene (PTFE) membranes has proven to be a simple alternative treatment that results in good maintenance of the alveolar bone for mediate/late implant placement. Therefore, this study compared the effect of alveolar preservation with the use of dense PTFE membranes, with and without xenograft material by Computerized tomography-based body composition (CTBC) analysis, after four months of the socket preservation procedure. A total of 29 teeth indicated for extraction. In the test group, the sockets were filled with bone graft biomaterial and subsequently coated with a dense PTFE membrane. In the control group, the sockets were filled with the blood clots and subsequently coated with a dense PTFE membrane. The results we found on the changes of the bone width and height after the procedures were: buccal plate: control group 0.46 mm, test group 0.91 mm; alveolar height: control group -0.41 mm, test group 0.35 mm; cervical third: control group -0.89 mm, test group -0.11 mm; middle third: control group -0.64, test group -0.50; and apical third: control group 0.09 mm, test group -0.14 mm. The use of a xenograft in conjunction with d-PTFE membranes proved to be superior to the use of the same membrane and blood clot only in regions of the crest, middle third, and alveolar height.

The Influence of Different Grafting Materials on Alveolar Ridge Preservation: a Systematic Review

Objectives

The purpose of the present review was to evaluate the effect of different bone substitutes used for alveolar ridge preservation on the post extraction dimensional changes.

Material and Methods

An electronic literature search in MEDLINE (PubMed), EMBASE (OVID) and Cochrane (CENTRAL) were performed, in addition to a manual search through all periodontics and implantology-related journals, up to December 2018. Inverse variance weighted means were calculated for all the treatment arms of the included trials for the quantitative analysis.

Results

Forty randomized controlled trials were included in the quantitative analysis. Dimensional changes were obtained from clinical measurements and three-dimensional imaging. The average amount of horizontal ridge resorption was 1.52 (SD 1.29) mm (allograft), 1.47 (SD 0.92) mm (xenograft), 2.31 (SD 1.19) mm (alloplast) and 3.1 (SD 1.07) mm for unassisted healing. Similarly, for all the evaluated parameters, the spontaneous healing of the socket led to higher bone loss rate than the use of a bone grafting material.

Conclusions

The utilization of a bone grafting material for alveolar ridge preservation reduces the resorption process occurring after tooth extraction. However, minimal differences in resorption rate were observed between allogeneic, xenogeneic and alloplastic grafting materials.

Alveolar ridge preservation using an open membrane approach for sockets with bone deficiency: A randomized controlled clinical trial

Background

Various approaches are used for alveolar ridge preservation (ARP); however, there is no standard method or material.

Purpose

To investigate the effect of ARP with a dense polytetrafluoroethylene (d‐PTFE) membrane and freeze‐dried irradiated allogenic bone for sockets with bone deficiency.

Materials and Methods

Thirty‐four patients (with sockets exhibiting ≥3 mm hard tissue loss in ≥1 walls) were randomized to undergo natural socket healing (control) or ARP with a d‐PTFE membrane and freeze‐dried irradiated allogenic bone (test group). After 4 months, horizontal and vertical ridge changes were measured using cone beam computed tomography.

Results

Ridge width at l mm below the ridge crest demonstrated significantly less change in the test group (median =2.3; Q1 = 0.6; Q3 = 4.3 mm) than in the control group (median =3.9; Q1 =2.6; Q3 = 7.8 mm; P = .021). There was no significant difference between the two groups in horizontal ridge changes at 3 and 5 mm below the crest or vertical changes (P > .05). Requirement for bone augmentation at implant placement was significantly reduced in the test group compared to the control group (P < .001).

Conclusion

ARP with a d‐PTFE membrane and freeze‐dried irradiated allogenic bone substitute reduced horizontal bone resorption in sockets with bone deficiency.

Ridge preservation following tooth extraction using mineralized freeze-dried bone allograft compared to mineralized solvent-dehydrated bone allograft: A randomized controlled clinical trial

BACKGROUND

Freeze dried bone allograft (FDBA) and solvent dehydrated bone allograft (SDBA) are both commonly used in alveolar ridge preservation. Previous studies have suggested SDBA may have advantages over FDBA due to a unique processing method. The primary objective of this study was to histologically compare the healing outcome between FDBA and SDBA when used for ridge preservation. Changes in morphometric ridge parameters were evaluated as a secondary outcome.

METHODS

Forty-four patients requiring extraction and ridge preservation were randomized into two groups: FDBA (control group) or SDBA (test group). Patients returned 12 weeks post-extraction and ridge preservation for implant placement. A bone core was taken in the planned implant osteotomy site and evaluated histomorphometrically to determine the percentage of vital bone, residual graft material, and connective/other tissue. Changes in clinical ridge dimensions were also evaluated for patients in both treatment groups.

RESULTS

The FDBA group showed a mean of 24.08% vital bone, 22.96% residual graft material, and 52.95% CT/other. The SDBA group showed a mean of 27.19% vital bone, 23.38% residual graft material, and 49.41% CT/other. No statistical differences were found between groups in the mean outcomes for histologic parameters or in dimensional change of the alveolar ridge.

CONCLUSION

This study provides the first histologic comparison between the wound healing of FDBA and SDBA over a 12-week healing period in a ridge preservation application. The findings suggest no significant benefit or drawback with the use of either FDBA or SDBA when comparing histomorphometric parameters or clinical dimensional changes.

Alveolar ridge preservation using a non-resorbable membrane: randomized clinical trial with biomolecular analysis

The aim of this randomized clinical trial was to evaluate the newly formed tissues in post-extraction sockets and to compare ridge dimensional changes with and without the use of a dense polytetrafluoroethylene membrane (d-PTFE). Twenty human extraction sockets (lower molars and premolars) received either an intentionally exposed d-PTFE membrane (test group) or no biomaterial (control group). After 4 months, during preparation for implant placement, bone and gingival tissues were collected for histological and biomolecular analysis. Clinically, the test and control groups showed mean gains of keratinized gingiva of 4.30±1.20mm and 2.50±2.20mm, respectively. A reduction in ridge width was observed in the control (2.90±2.70mm) and test (3.30±2.00mm) groups. The bone height alteration ranged from a reduction of 0.12±1.60mm to a gain of 0.60±3.60mm on average for both groups. Analysis of gene expression (OPG/RANKL) in gingival fibroblasts and osteoblasts revealed no difference between the two groups. Ridge preservation using the d-PTFE membrane increased the formation of keratinized tissue. A reduction in width and mild reduction/gain in height of the alveolar ridge was observed in both groups. The membrane had no influence on the healing process.

Guided bone regeneration: materials and biological mechanisms revisited

Guided bone regeneration (GBR) is commonly used in combination with the installment of titanium implants. The application of a membrane to exclude non‐osteogenic tissues from interfering with bone regeneration is a key principle of GBR. Membrane materials possess a number of properties which are amenable to modification. A large number of membranes have been introduced for experimental and clinical verification. This prompts the need for an update on membrane properties and the biological outcomes, as well as a critical assessment of the biological mechanisms governing bone regeneration in defects covered by membranes. The relevant literature for this narrative review was assessed after a MEDLINE/PubMed database search. Experimental data suggest that different modifications of the physicochemical and mechanical properties of membranes may promote bone regeneration. Nevertheless, the precise role of membrane porosities for the barrier function of GBR membranes still awaits elucidation. Novel experimental findings also suggest an active role of the membrane compartment per se in promoting the regenerative processes in the underlying defect during GBR, instead of being purely a passive barrier. The optimization of membrane materials by systematically addressing both the barrier and the bioactive properties is an important strategy in this field of research.

Ridge Preservation Comparing a Nonresorbable PTFE Membrane to a Resorbable Collagen Membrane: A Clinical and Histologic Study in Humans

PURPOSE

The primary aim of this randomized, controlled, blinded clinical trial was to compare the effect of a resorbable collagen membrane (CM group) versus a nonresorbable high-density polytetrafluoroethylene membrane (PTFE group) on the clinical and histologic outcomes of a ridge preservation procedure.

MATERIALS AND METHODS

All 24 sites received an intrasocket cancellous allograft and a buccal overlay bovine derived xenograft.

RESULTS

The change in horizontal crestal ridge width was -1.4 ± 1.2 mm for the CM group, whereas the PTFE group lost -2.2 ± 1.5 mm, which was not statistically significant between groups (P > 0.05). Vertical ridge height change was -1.2 ± 1.5 for the CM group, whereas the PTFE group lost -0.5 ± 1.6, which was not significantly different between groups (P > 0.05). The percent vital bone was similar and not significantly different between groups. Primary closure was not obtained and the exposed membrane portion over the socket opening healed with keratinized tissue.

CONCLUSION

The choice of a resorbable versus a nonresorbable barrier membrane did not affect the clinical or the histologic outcome of ridge preservation treatment.

Interventions for replacing missing teeth: alveolar ridge preservation techniques for dental implant site development

BACKGROUND

Alveolar bone changes following tooth extraction can compromise prosthodontic rehabilitation. Alveolar ridge preservation (ARP) has been proposed to limit these changes and improve prosthodontic and aesthetic outcomes when implants are used.

OBJECTIVES

To assess the clinical effects of various materials and techniques for ARP after tooth extraction compared with extraction alone or other methods of ARP, or both, in patients requiring dental implant placement following healing of extraction sockets.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 22 July 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2014, Issue 6), MEDLINE via OVID (1946 to 22 July 2014), EMBASE via OVID (1980 to 22 July 2014), LILACS via BIREME (1982 to 22 July 2014), the Meta Register of Current Controlled Trials (to 22 July 2014), ClinicalTrials.gov (to 22 July 2014), the World Health Organization International Clinical Trials Registry Platform (to 22 July 2014), Web of Science Conference Proceedings (1990 to 22 July 2014), Scopus (1966 to 22 July 2014), ProQuest Dissertations and Theses (1861 to 22 July 2014) and OpenGrey (to 22 July 2014). A number of journals were also handsearched. Trial authors were contacted to identify unpublished randomised controlled trials. There were no restrictions regarding language and date of publication in the searches of the electronic databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) on the use of alveolar ridge preservation techniques with at least six months of follow-up. Outcome measures were: changes in the bucco-lingual/palatal width of alveolar ridge, changes in the vertical height of the alveolar ridge, complications, the need for additional augmentation prior to implant placement, aesthetic outcomes, implant failure rates, peri-implant marginal bone level changes, changes in probing depths and clinical attachment levels at teeth adjacent to the extraction site, and complications of future prosthodontic rehabilitation.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently and assessed risk of bias for each included trial. Corresponding authors were contacted to obtain missing information. Results were combined using random-effects models with mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes, with 95% confidence intervals (95% CI). We constructed 'Summary of findings' tables to present the main findings.

MAIN RESULTS

A total of 50 trials were potentially eligible for inclusion, of which 42 trials were excluded. We included eight RCTs with a total of 233 extraction sites in 184 participants. One trial was judged to be at unclear risk of bias and the remaining trials were at high risk of bias. From two trials comparing xenograft with extraction alone (70 participants, moderate quality evidence), there was some evidence of a reduction in loss of alveolar ridge height (MD -2.60 mm; 95% CI -3.43 to -1.76) and width (MD -1.97 mm; 95% CI -2.48 to -1.46). This was also found in one trial comparing allograft with extraction (24 participants, low quality evidence): ridge height (MD -2.20 mm; 95% CI -0.75 to -3.65) and width (MD - 1.40 mm; 95% CI 0.00 to -2.80) and height. From two RCTs comparing alloplast versus xenograft no evidence was found that either ridge preservation technique caused a smaller reduction in loss of ridge height (MD -0.35 mm; 95% CI -0.86 to 0.16) or width (MD -0.44 mm; 95% CI -0.90 to 0.02; two trials (55 participants); moderate quality evidence). There was insufficient evidence to determine whether there are clinically significant differences between different ARP techniques and extraction based on the need for additional augmentation prior to implant placement, complications, implant failure, or changes in peri-implant marginal bone levels and probing depths of neighbouring teeth. We found no trials which evaluated parameters relating to clinical attachment levels, specific aesthetic or prosthodontic outcomes.

AUTHORS' CONCLUSIONS

There is limited evidence that ARP techniques may minimise the overall changes in residual ridge height and width six months after extraction. There is also lack of evidence of any differences in implant failure, aesthetic outcomes or any other clinical parameters due to the lack of information or long-term data. There is no convincing evidence of any clinically significant difference between different grafting materials and barriers used for ARP. Further long term RCTs that follow CONSORT guidelines (www.consort-statement.org) are necessary.

Clinical and histologic outcomes of socket grafting after flapless tooth extraction: a systematic review of randomized controlled clinical trials

STATEMENT OF PROBLEM

Several biomaterials and techniques have been reported for socket grafting and alveolar ridge preservation. However, the evidence for clinical and histologic outcomes for socket grafting with different types of materials in flapless extraction is not clear.

PURPOSE

The purpose of this systematic review was to analyze the outcomes of a socket grafting procedure performed with flapless extraction of teeth in order to determine which graft material results in the least loss of socket dimensions, the maximum amount of vital bone, the least remnant graft material, and the least amount of connective tissue after a minimum of 12 weeks of healing. Secondary outcomes, including the predictability of regenerating deficient buccal bone, necessity of barrier membranes, and coverage with autogenous soft tissue graft, were also evaluated.

MATERIAL AND METHODS

An electronic search for articles in the English-language literature was performed independently by multiple investigators using a systematic search process with the PubMed search engine. After applying predetermined inclusion and exclusion criteria, the final list of randomized controlled clinical trials (RCTs) for flapless extraction and socket grafting was analyzed to derive results for the various objectives of the study.

RESULTS

The initial electronic search resulted in 2898 titles. The systematic application of inclusion and exclusion criteria resulted in 32 RCTs studying 1354 sockets, which addressed the clinical and histologic outcomes of flapless extraction with socket grafting and provided dimensional and histologic information at or beyond the 12-week reentry period. From these RCTs, the mean loss of buccolingual width at the ridge crest was lowest for xenografts (1.3 mm), followed by allografts (1.63 mm), alloplasts (2.13 mm), and sockets without any socket grafting (2.79 mm). Only 3 studies reported on loss of width at 3 mm below the ridge crest. The mean loss of buccal wall height from the ridge crest was lowest for xenografts (0.57 mm) and allografts (0.58 mm), followed by alloplasts (0.77 mm) and sockets without any grafting (1.74 mm). The mean histologic outcomes at or beyond the 12-week reentry period revealed the highest vital bone content for sockets grafted with alloplasts (45.53%), followed by sockets with no graft material (41.07%), xenografts (35.72%), and allografts (29.93%). The amount of remnant graft material was highest for sockets grafted with allografts (21.75%), followed by xenografts (19.3%) and alloplasts (13.67%). The highest connective tissue content at the time of reentry was seen for sockets with no grafting (52.53%), followed by allografts (51.03%), xenografts (44.42%), and alloplast (38.39%). Data for new and emerging biomaterials such as cell therapy and tissue regenerative materials were not amenable to calculations because of biomaterial heterogeneity and small sample sizes.

CONCLUSIONS

After flapless extraction of teeth, and using a minimum healing period of 12 weeks as a temporal measure, xenografts and allografts resulted in the least loss of socket dimensions compared to alloplasts or sockets with no grafting. Histologic outcomes after a minimum of 12 weeks of healing showed that sockets grafted with alloplasts had the maximum amount of vital bone and the least amount of remnant graft material and remnant connective tissue. There is a limited but emerging body of evidence for the predictable regeneration of deficient buccal bone with socket grafting materials, need for barrier membranes, use of tissue engineering, and use of autogenous soft tissue grafts from the palate to cover the socket.

Evaluation of the zone of keratinized tissue using exposed acellular dermal matrix over tooth extraction sites: a randomized controlled clinical trial

BACKGROUND

The presence of an adequate zone of keratinized tissue has been associated with implant health. This study evaluated the zone of keratinized tissue using exposed acellular dermal matrix (ADM) over extraction sites.

MATERIAL AND METHODS

Fifteen sites received ADM, and fifteen control sites received no biomaterial. All sites were sutured with no attempt to achieve primary closure. Initial measurements of buccal and lingual keratinized tissue were taken from the mucogingival line (MGL) to the most coronal gingival margins. Final measurements were taken from the buccal MGL to the lingual MGL 90 days after surgery. Gingival biopsies were taken before implant placement.

RESULTS

Test and control groups exhibited a mean value of 4.40 ± 1.45 mm and 1.40 ± 1.40 mm, respectively. The newly formed tissue revealed similar histological aspect of normal keratinized tissue.

CONCLUSION

Exposed ADM used over tooth extraction sockets can predictably be used to increase the zone of keratinized tissue.

Enhanced bone regeneration with a novel synthetic bone substitute in combination with a new natural cross-linked collagen membrane: radiographic and histomorphometric study

OBJECTIVES

4Bone is a fully synthetic bioactive bone substitute composed of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (ß-TCP). This study aimed to investigate the effect of resorbable collagen membranes (RCM) on critical size defects in rabbit tibiae filled with this novel biphasic calcium phosphate at 15, 30, 45, and 60 days by radiological and histomorphometric analysis.

MATERIAL AND METHODS

Three critical size defects of 6 mm diameter were created in both tibiae of 20 New Zealand rabbits and divided into three groups according to the filling material: Group A (4Bone), Group B (4Bone plus RCM), and Group C (unfilled control group). At each of the four study periods, five rabbits were sacrificed. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy.

RESULTS

At the end of treatment, radiological analysis found that cortical defect closure was greater in Group B than Group A, and radiopacity was clearly lower and more heterogeneous in Group A cortical defects than in Group B. There was no cortical defect closure in Group C. Histomorphometric evaluation showed significant differences in newly formed bone and cortical closure in Group B compared with Groups A and C, with the presence of higher density newly formed bone in cortical and medullar zones.

CONCLUSIONS

Biphasic calcium phosphate functioned well as a scaffolding material allowing bone ingrowth and mineralization. The addition of absorbable collagen membranes enhanced bone gain compared with non-membrane-treated sites. This rabbit study provides radiological and histological evidence confirming the suitability of this new material for guided tissue regeneration of critical defects.

Rehabilitation of a patient with gunshot injury through the iliac graft and implant-retained restorations with a 3-year follow-up: a brief clinical study

Trauma is one of the most common causes of teeth loss. Assault with a gunshot and bullet shot is life threatening, and for patients who survive the injury, it results in hard and soft tissue loss in the tissues and organs crossed by the bullet. The tissue loss results in the loss of structure and function. Rehabilitation of these patients to function and aesthetics requires surgical and prosthodontic procedures over time. This report is of a 24-year-old male patient who had a bullet injury resulting in hard and soft tissue deficiency. The ridge deficiency was augmented with iliac bone graft, and 3 months later, implants were placed. Five months later, hybrid prosthesis was delivered. At 3-year follow-up visit, the hybrid prosthesis was replaced with porcelain fused to a metal bridge. The bone levels on all the implants were stable.

Alveolar ridge preservation techniques: a systematic review and meta-analysis of histological and histomorphometrical data

AIM

The aim of this article was to systematically review histological and histomorphometrical data from literature that provide information regarding the effect of alveolar ridge preservation procedures on healing after tooth extraction in humans.

MATERIALS AND METHODS

The MEDLINE-PubMed and the Cochrane CENTRAL databases were searched up to September 2012; 38 papers were selected from 646 founded. A meta-analysis was performed regarding the variations in the mean percentage of Bone, Connective Tissue and Residual Graft Material between three different types of Procedures.

RESULTS

The highest value regarding bone percentages is produced at 3 months by Procedures with Allografts (54.4%), while the lowest is obtained, at 5 months, by those using Xenografts (23.6%). Referring to connective tissue, the highest and lowest values are shown at 7 months, with Allografts (67%) and Alloplasts (27.1%), respectively. Regarding residual graft material, the lowest rates are displayed by Procedures with Allografts (12.4-21.11%), while those using Xenografts and Alloplasts showed the best results at 7 months (37.14 and 37.23%). No statistical difference was found.

CONCLUSIONS

With the limitations due to the features of the selected papers, no major histological and histomorphometrical differences arose among different procedures or when compared to spontaneous healing. Thus, it might be argued that in preserved sites it is unnecessary to wait over 3 to 4 months prior to implant insertion.

Influence of biphasic β-TCP with and without the use of collagen membranes on bone healing of surgically critical size defects. A radiological, histological, and histomorphometric study

OBJECTIVES

The aim of this study was to investigate, by means of radiological and histomorphometric analysis, the effect of resorbable collagen membranes on critical size defects (CSD) in rabbit tibiae filled with biphasic calcium phosphate.

MATERIALS AND METHODS

Three CSD of 6 mm diameter were created in both tibiae of 20 New Zealand rabbits and divided into three groups according to the filling material: Group A (Ossceram), Group B (Ossceram plus Alveoprotect membrane), and Group C (unfilled control group). Five animals from each group were sacrificed after 15, 30, 45, and 60 days. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy.

RESULTS

At the end of treatment, radiological analysis found that cortical defect closure was greater in Group B than Group A, and radiopacity was clearly lower and more heterogeneous in the Group A cortical defects than in Group B. There was no cortical defect closure in Group C. Histomorphometric evaluation showed significant differences in newly formed bone and cortical closure in Group B compared with Groups A and C, with the presence of higher density newly formed bone in cortical and medullar zones. There was no cortical defect closure or medullar bone formation in Group C.

CONCLUSIONS

Biphasic calcium phosphate functioned well as a scaffolding material allowing mineralized tissue formation. Furthermore, the addiction of absorbable collagen membranes enhanced bone gain compared with non-membrane-treated sites.

High-density polytetrafluoroethylene membranes in guided bone and tissue regeneration procedures: a literature review

Expanded polytetrafluoroethylene (e-PTFE) has been used successfully as a membrane barrier for regeneration procedures. However, when exposed to the oral cavity, its high porosity increases the risk of early infection, which can affect surgical outcomes. An alternative to e-PTFE is non-expanded and dense polytetrafluoroethylene (n-PFTE), which results in lower levels of early infection following surgical procedures. The aim of this literature review was to analyze and describe the available literature on n-PFTE, report the indications for use, advantages, disadvantages, surgical protocols, and complications. The medical databases Medline-PubMed and Cochrane Library were searched and supplemented with a hand search for reports published between 1980 and May 2012 on n-PTFE membranes. The search strategy was limited to animal, human, and in vitro studies in dental journals published in English. Twenty-four articles that analyzed the use of n-PTFE as a barrier membrane for guided tissue regeneration and guided bone regeneration around teeth and implants were identified: two in vitro studies, seven experimental studies, and 15 clinical studies. There is limited clinical and histological evidence for the use of n-PTFE membranes at present, with some indications in guided tissue regeneration and guided bone regeneration in immediate implants and fresh extraction sockets.

Socket Preservation and Sinus Augmentation Using a Medical Grade Calcium Sulfate Hemihydrate and Mineralized Irradiated Cancellous Bone Allograft Composite

Regeneration and preservation of bone after the extraction of a tooth are necessary for the placement of a dental implant. The goal is to regenerate alveolar bone with minimal postoperative pain. Medical grade calcium sulfate hemihydrate (MGCSH) can be used alone or in combination with other bone grafts; it improves graft handling characteristics and particle containment of particle-based bone grafts. In this case series, a 1:1 ratio mix of MGCSH and mineralized irradiated cancellous bone allograft (MICBA) was mixed with saline and grafted into an extraction socket in an effort to maintain alveolar height and width for future implant placement. MGCSH can be used in combination with other bone grafts and can improve handling characteristics and graft particle containment of particle-based bone grafts. In the cases described, we found that an MGCSH:MICBA graft can potentially be an effective bone graft composite. It has the ability to act as a space maintainer and as an osteoconductive trellis for bone cells, thereby promoting bone regeneration in the extraction socket. MGCSH, a cost-effective option, successfully improved MICBA handling characteristics, prevented soft tissue ingrowth, and assisted in the regeneration of bone.

Ridge preservation comparing socket allograft alone to socket allograft plus facial overlay xenograft: a clinical and histologic study in humans

BACKGROUND

Previous studies of ridge preservation showed a loss of ≈18% or 1.5 mm of crestal ridge width in spite of treatment. The primary aim of this randomized, controlled, masked clinical trial is to compare a socket graft to the same treatment plus a buccal overlay graft, both with a polylactide membrane, to determine if loss of ridge width can be prevented by use of an overlay graft.

METHODS

Twelve patients who served as positive controls received an intrasocket mineralized cancellous allograft (socket group), and 12 patients received the same socket graft procedure plus buccal overlay cancellous xenograft (overlay group). Horizontal ridge dimensions were measured with a digital caliper, and vertical ridge changes were measured from a stent. Before implant placement, at 4 months, a trephine core was obtained for histologic analysis.

RESULTS

The mean horizontal ridge width at the crest for the socket group decreased from 8.7 ± 1.0 to 7.1 ± 1.5 mm for a mean loss of 1.6 ± 0.8 mm (P <0.05), whereas the same measurement for the overlay group decreased from 8.4 ± 1.4 to 8.1 ± 1.4 mm for a mean loss of 0.3 ± 0.9 mm (P >0.05). The overlay group was significantly different from the socket group (P <0.05). Histologic analysis revealed that the socket group had 35% ± 16% vital bone, and the overlay group had 40% ± 16% (P >0.05).

CONCLUSIONS

The overlay treatment significantly prevented loss of ridge width and preserved or augmented the buccal contour. The socket and overlay groups healed with a high percentage of vital bone.

Is socket healing conditioned by buccal plate thickness? A clinical and histologic study 4 months after mineralized human bone allografting

OBJECTIVE

The aim of this study was to clinically and histologically analyze the healing of grafted sockets by mineralized human bone allograft (MHBA) and nongrafted sockets, correlating the results with buccal plate thickness.

MATERIAL AND METHODS

Thirty-one sockets were randomly split into control (CG) and treatment (MHBA grafted) (TG) groups and, subsequently, into four subgroups according to buccal plate thickness: a ≤ 1 mm and b > 1 mm. Ridge thickness, depth, and height were monitored. Four months after, at implant placement, a bone core biopsy for histologic and morphometric analyses was taken.

RESULTS

The differences of buccal height (TG-a -0.27 and CG-a -1.17 mm) and width (TG-a 0.55 and CG-a 2.67 mm, TG-b 0.12 and CG-b 1.17 mm) were statistically significant. The increase in bone amount CG-b (28.17%) compared with CG-a (16.98%) was statistically significant. Soft tissue amount of TG-b (54.21%) and TG-a (56.91%) was lower than that of CG-b (71.83%) and CG-a (83.01%), both being statistically significant (P = 0.002).

CONCLUSIONS

The results proved that thin buccal plates had a worse outcome on socket healing and that network formation by MBHA not only predisposes a successful implant insertion but also acts as size keeper.

Application of acellular dermal matrix in reconstruction of oral mucosal defects in 36 cases

PURPOSE

Artificial grafts have been investigated for use in the repair of oral mucosal defects. The aim of this retrospective study was to present the outcomes of the use of acellular dermal matrix (ADM) grafts to repair oral mucosal defects.

MATERIALS AND METHODS

Data from 36 patients with oral mucosal defects reconstructed with ADM grafts from 2003 through 2009 were reviewed. All patients were followed-up for at least 6 months to observe the graft repair, wound-healing time, contracture, color, infection, pain, immunologic reaction, texture of the graft, and clinical course. Graft success was defined as the ADM graft being replaced by new mucosa-like tissue and the oral mucosal defect being covered with the new mucosa-like tissue. Any evidence of incomplete graft re-epithelialization or graft sloughing was considered a graft failure (complete or incomplete).

RESULTS

Of the 36 cases, 34 grafts (94.4%) were successfully replaced with new mucosa-like tissues and only 2 grafts (5.6%) failed. No complaints such as pain, immunologic reaction, or infection were observed during the follow-up. Mild graft contraction occurred in 7 patients with lip or buccal defects, especially at approximately 3 to 5 weeks after the reconstructive surgery.

CONCLUSIONS

The ADM grafts for oral mucosal defects were safe and effective. The present data support the clinical application of ADM grafts in reconstructing oral mucosal defects caused by various oral diseases.

Effect of acellular dermal matrix as a delivery carrier of adipose-derived mesenchymal stem cells on bone regeneration

The purpose of this study is to evaluate the effect of acellular dermal matrix (ADM) as a delivery carrier of adipose-derived mesenchymal stem cells (ASCs) on bone regeneration in athymic murine calvarial bone defect. Paired-critical size defects in nude rat skull were made. The right-side defects received ASCs/ADM or only ADM, whereas the left-side defect was not treated. In 3D images, new bone formation in the ASCs/ADM group was apparent at 4 wk, but in the ADM group at 8 wk. At 4 and 8 wk, bone mineral density and tissue volume in rats that received ASCs/ADM were significantly greater than rats that received ADM and control groups. Histological examination revealed that the defect was repaired by bone in the ASCs/ADM group, whereas only minimal bone island with fibrous connection was observed in the control group. In histomorphometric analysis, the total healing score in the ASCs/ADM group at 4 wk was significantly higher than the ADM and negative control group, whereas the score of 8 wk was similar between the ASCs/ADM and ADM group. ASCs/ADM implants promote new bone formation more rapidly than ADM only or no treatment. ADM seeded with ASCs may be potentially useful as a future biomaterial option in bone implants.

Cell-mediated and direct gene therapy for bone regeneration

INTRODUCTION

Bone regeneration is required for the treatment of fracture non/delayed-unions and bone defects. However, most current treatment modalities have limited efficacy, and newer therapeutic strategies, such as gene therapy, have substantial benefit for bone repair and regeneration.

AREAS COVERED

This review discusses experimental and clinical applications of cell-mediated and direct gene therapy for bone regeneration. The review covers literature on this subject from 2000 to February 2012.

EXPERT OPINION

Direct gene therapy using various viral and non-viral vectors of cell-mediated genes has been demonstrated to induce bone regeneration, although use of such vectors has shown some risk in human application. Osteoinductive capability of a number of progenitor cells isolated from bone marrow, fat, muscle and skin tissues, has been demonstrated by genetic modification with osteogenic genes. Cell-mediated gene therapy using such osteogenic gene-expressing progenitor cells has shown promising results in promoting bone regeneration in extensive animal work in recent years.