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

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.

Clinical evaluation of different alveolar ridge preservation techniques after tooth extraction: a randomized clinical trial

OBJECTIVE

The aim of the present randomized controlled trial (RCT) was to evaluate the efficacy of different alveolar ridge preservation (ARP) techniques on dimensional alterations after tooth extraction, based on clinical measurements.

BACKGROUND

Alveolar ridge preservation (ARP) is a common procedure in every day clinical practice, when dental implants are involved in treatment planning. In ARP procedures, a bone grafting material is combined with a socket sealing (SS) material in order to compensate the alveolar ridge dimensional alterations after tooth extraction. Xenograft and allograft are the most frequently used bone grafts in ARP, while free gingival graft (FGG), collagen membrane, and collagen sponge (CS) usually applied as SS materials. The evidence comparing xenograft and allograft directly in ARP procedure is scarce. In addition, FGG is usually combined with xenograft as SS material, while the evidence combing allograft with FGG is absent. Moreover, CS could probably be an alternative choice in ARP as SS material, since it has been used in previous studies but more clinical trials are required to evaluate its effectiveness.

MATERIALS AND METHODS

Forty-one patients were randomly assigned in four treatment groups: (A) freeze-dried bone allograft (FDBA) covered with collagen sponge (CS), (B) FDBA covered with free gingival graft (FGG), (C) demineralized bovine bone mineral xenograft (DBBM) covered with FGG, and (D) FGG alone. Clinical measurements were performed immediately after tooth extraction and 4 months later. The related outcomes pertained to both vertical and horizontal assessment of bone loss.

RESULTS

Overall, groups A, B, and C presented significantly less vertical and horizontal bone resorption compared to group D. No statistically significant difference was observed between allograft and xenograft, except for the vertical bone resorption at the buccal central site, where xenograft showed marginally statistically significantly reduced bone loss compared to allograft (group C vs group B: adjusted β coef: 1.07 mm; 95%CI: 0.01, 2.10; p = 0.05). No significant differences were observed in hard tissue dimensions when CS and FGG were applied over FDBA.

CONCLUSIONS

No differences between FDBA and DBBM could practically be confirmed. In addition, CS and FGG were equally effective socket sealing materials when combined with FDBA, regarding bone resorption. More RCTs are needed to compare the histological differences between FDBA and DBBM and the effect of CS and FGG on soft tissue dimensional changes.

CLINICAL RELEVANCE

Xenograft and allograft were equally efficient in ARP 4 months after tooth extraction in horizontal level. Xenograft maintained the mid-buccal site of the socket marginally better than the allograft, in vertical level. FGG and CS were equally efficient as SS materials regarding the hard tissue dimensional alterations.

TRIAL REGISTRATION

Clinical trial registration Number: NCT04934813 (clinicaltrials.gov).

Enamel matrix derivative for alveolar ridge preservation: A randomized controlled trial

OBJECTIVE

The aims of this clinical trial were to evaluate the radiographic dimensional changes in alveolar ridge and patient-reported outcomes following tooth extraction and alveolar ridge preservation (ARP) using either deproteinized bovine bone mineral (DBBM) with EMD or DBBM alone.

METHODS

Participants requiring at least one posterior tooth extraction and ARP were randomly allocated into two treatment groups: ARP using either DBBM with EMD or DBBM alone. Cone-beam computed tomography (CBCT) images were recorded immediately prior to extraction and at 6 months. Changes in alveolar ridge height (ARH) and alveolar ridge width (ARW) at 1, 3, and 5 mm were recorded.

RESULTS

A total of 18 participants with 25 preserved sites were evaluated. ARH and ARW changed significantly from baseline to 6 months for both treatment groups but the difference between the groups was not statistically significant over the 6-month follow-up period (ARH: DBBM/EMD 1.26 ± 1.53 mm vs. DBBM 2.26 ± 1.60 mm; ARW-1 DBBM/EMD 1.98 ± 1.80 mm vs. DBBM 2.34 ± 1.89 mm). A significant difference, favoring DBBM with EMD group, was observed in percentage of sites that had less than 1 mm loss in ARH (54.5% sites in DBBM/EMD group vs. 14.3% sites in DBBM alone group). The participants' perception of bruising, bleeding, and pain in the first two postoperative days was significantly in favor of DBBM alone group.

CONCLUSIONS

There were no significant differences in radiographic mean measurements of ARH and ARW following ARB with DBBM and EMD or DBBM alone.

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 healing time on the outcomes of alveolar ridge preservation using a collagenated bovine bone xenograft: A randomized clinical trial

AIM

To evaluate the healing outcomes in non-molar post-extraction sockets filled with deproteinized bovine bone mineral with collagen (DBBM-C) as a function of time.

MATERIALS AND METHODS

Patients in need of non-molar tooth extraction were randomly allocated into one of three groups according to the total healing time (A-3 months; B-6 months; C-9 months). The effect of alveolar ridge preservation (ARP) therapy via socket filling using DBBM-C and socket sealing with a porcine collagen matrix (CM) was assessed based on a panel of clinical, digital, histomorphometric, implant-related, and patient-reported outcomes.

RESULTS

A total of 42 patients completed the study (n = 14 in each group). Histomorphometric analysis of bone core biopsies obtained at the time of implant placement showed a continuous increase in the proportion of mineralized tissue with respect to non-mineralized tissue, and a decrease in the proportion of remaining xenograft material over time. All volumetric bone and soft tissue contour assessments revealed a dimensional reduction of the alveolar ridge overtime affecting mainly the facial aspect. Linear regression analyses indicated that baseline buccal bone thickness is a strong predictor of bone and soft tissue modelling. Ancillary bone augmentation at the time of implant placement was needed in 16.7% of the sites (A:2; B:1; C:4). Patient-reported discomfort and wound healing index scores progressively decreased over time and was similar across groups.

CONCLUSIONS

Healing time influences the proportion of tissue compartments in non-molar post-extraction sites filled with DBBM-C and sealed with a CM. A variable degree of alveolar ridge atrophy, affecting mainly the facial aspect, occurs even after performing ARP therapy. These changes are more pronounced in sites exhibiting thin facial bone (≤1 mm) at baseline (Clinicaltrials.gov NCT03659617).

CBCT Evaluation of Quality and Quantity of Bones for Immediate Implant Treatment Planning in Central Incisor Area in relation to Arch Form

Understanding the quality of the ridge and facial cortical bone in the aesthetic zone is important for treatment with an immediate dental implant. This study aimed to analyze bone density and widths of the facial cortical bone and alveolar ridge at the central incisors in relation to arch form. A total of 400 teeth from 100 cone-beam CT images were divided equally between the upper and lower central incisors. The central incisor area was assessed for the width of the facial cortical and alveolar bones at three different points (3 mm, 6 mm, and 9 mm from the cementoenamel junction). Arch forms and densities of cortical and cancellous bones in the interradicular regions were evaluated. The difference in facial cortical bone thickness at 3 points was smaller for the upper teeth than for the lower teeth on both sides. The alveolar bone width was higher in the maxilla than the mandible with highly significant differences (P < 0.001). The highest bone density was at the buccal aspect of the mandible (897.36 ± 136.72 HU), while the lowest density was at the cancellous bone of the maxilla (600.37 ± 126.63 HU). The dominant arch form was ovoid 71%, followed by square 20% and the tapering arch form 10%. The tapering arch form has the highest alveolar bone width in the upper jaw without statistical significance. The facial cortical bone thickness needs to be evaluated before implantation in the anterior region because it is less than two millimeters in both jaws. CBCT is important for the immediate implant. The ovoid shape was the dominant arch form.

Flapless Decoronation: A Minimally Invasive Approach

Traumatic injuries to the permanent dentition are most common in children. In severe dentoalveolar injuries, especially avulsion and intrusion, dentoalveolar ankylosis is a common complication, leading to adverse effects on the developing alveolar bone and interfering with the eruption of the adjacent teeth. The decoronation procedure was suggested in 1984 to reduce these side effects related to ankylosis. The objective of the current publication is to describe a minimally invasive, flapless decoronation procedure aimed to minimize and simplify the surgical procedure of decoronation, and ease its clinical acceptance, particularly in young children. The technique is described in a detailed protocol and demonstrated in two cases. Under local anesthesia, the dental crown is removed, and the root is reduced by 1.5-2.0 mm apically to the marginal bone crest. The root canal content is then removed, allowing it to fill with blood. The socket is coronally sealed with a porcine-derived collagen matrix (PDCM) sutured using the "parachute" technique over the resected root, allowing close adaptation to the surrounding soft tissue. In conclusion, the presented technique of flapless decoronation is a modification of the classic decoronation procedure, which can be used as a minimally invasive technique to simplify the surgical procedure and the post-operative process.

An antibacterial chitosan-based hydrogel as a potential degradable bio-scaffold for alveolar ridge preservation

Post-extraction, preventing the absorption of alveolar ridge to retain the supporting construction for implanted teeth is still a challenge. Herein, we developed modified chitosan (CS)-based hydrogel using N-hydroxysuccinimide-terminated 4-arm poly (ethylene glycol) (4-arm-PEG-NHS) as the crosslinking agent, after introducing it to the polyhexamethyleneguanidine hydrochloride (PHMB) solution, CS/PEG/PHMB hydrogel with the enhanced antibacterial properties was obtained. The CS/PEG hydrogel and CS/PEG/PHMB hydrogel prepared here showed excellent mechanical strength and their compressive strength could reach 440 kPa and 450 kPa, respectively. The composite hydrogel was designed to be directional porous, low cytotoxic, pH-sensitive, and degradable. The weight of the hydrogel was reduced by ∼30% after 28 days of incubation, and it swelled significantly in the acidic condition while it did not swell in the neutral and weakly alkaline environments, indicating an excellent biodegradability in the inflammation site. In vitro antibacterial experiments showed that the bacteriostatic rate of the CS/PEG/PHMB hydrogel against S. aureus was above 90%, which could effectively inhibit the spread of the bacteria and inflammation in the alveolar ridge. Additionally, the hybrid hydrogels demonstrated good biocompatibility with the NIH 3T3 fibroblast cells. Overall, the CS/PEG/PHMB hydrogel is a promising biological scaffold for maintaining the alveolar ridge and subsequently improving the success rate of the dental implant.

Alveolar ridge preservation reduces the need for ancillary bone augmentation in the context of implant therapy

Background

There is limited information on the need for bone augmentation in the context of delayed implant placement whether alveolar ridge preservation (ARP) is previously performed or not. The primary aim of this retrospective cohort study was to evaluate the efficacy of ARP therapy after tooth extraction compared with unassisted socket healing (USH) in reducing the need for ancillary bone augmentation before or at the time of implant placement.

Methods

Adult subjects that underwent non‐molar single tooth extraction with or without simultaneous ARP therapy were included in this study. Cone beam computed tomography scans obtained before tooth extraction and after a variable healing period were used to record the baseline facial bone thickness and to virtually plan implant placement according to a standard method. A logistic regression model was used to evaluate the effect of facial alveolar bone thickness upon tooth extraction and baseline therapy (USH or ARP) on the need for additional bone augmentation, adjusting for several covariates (i.e., age, sex, baseline KMW, and tooth type).

Results

One hundred and forty subjects that were equally distributed between both baseline therapy groups constituted the study population. Implant placement was deemed virtually feasible in all study sites. Simultaneous bone augmentation was considered necessary in 60% and 11.4% of the sites in the USH and ARP group, respectively. Most of these sites (64.2% in the USH group and 87.5% in the ARP group) exhibited a thin facial bone phenotype (<1 mm) at baseline. Logistic regression revealed that the odds of not needing ancillary bone augmentation were 17.8 times higher in sites that received ARP therapy. Furthermore, the need for additional bone augmentation was reduced 7.7 times for every 1 mm increase in facial bone thickness, regardless of baseline therapy.

Conclusions

Based on a digital analysis, ARP therapy, compared with USH, and thick facial alveolar bone largely reduce the need for ancillary bone augmentation at the time of implant placement in non‐molar sites.

Dimensional and histomorphometric evaluation of biomaterials used for alveolar ridge preservation: a systematic review and network meta-analysis

OBJECTIVES

This systematic review and network meta-analysis aimed to answer to the following questions: (a) In patients undergoing alveolar ridge preservation after tooth extraction, which grafting material best attenuates horizontal and vertical ridge resorption, as compared to spontaneous healing?, and (b) which material(s) promotes bone formation in the extraction socket?

MATERIALS AND METHODS

The MEDLINE, SCOPUS, CENTRAL, and EMBASE databases were screened in duplicate for RCTs up to March 2021. Two independent authors extracted the data and assessed the risk of bias of the included studies. Primary outcomes were ridge horizontal and vertical dimension changes and new bone formation into the socket. Both pairwise and network meta-analysis (NMA) were undertaken to obtain estimates for primary outcomes and compare different grafting materials.

RESULTS

Eighty-eight RCTs were included, with a total of 2805 patients and 3073 sockets. Overall, a total of 1740 sockets underwent alveolar ridge preservation with different materials (1432 were covered by a membrane). Pairwise meta-analysis showed that, as compared to spontaneous healing, all materials statistically significantly reduced horizontal and vertical shrinkage. According to the multidimensional scale ranking of the NMA, xenografts (XG) and allografts (AG), alone or combined with bioactive agents (Bio + AG), were the most predictable materials for horizontal and vertical ridge dimension preservation, while platelet concentrates performed best in the percentage of new bone formation.

CONCLUSIONS

Alveolar ridge preservation is effective in reducing both horizontal and vertical shrinkage, as compared to untreated sockets. NMA confirmed the consistency of XG for ridge dimension preservation, but several other materials and combinations like AG, Bio + AG, and AG + alloplasts, produced even better results than XG in clinical comparisons. Further evidence is needed to confirm the value of such alternatives to XG for alveolar ridge preservation. Bio + AG performed better than the other materials in preserving ridge dimension and platelet concentrates in new bone formation. However, alloplasts, xenografts, and AG + AP performed consistently good in majority of the clinical comparisons.

CLINICAL RELEVANCE

XG and Bio + AG demonstrated significantly better performance in minimizing post-extraction horizontal and vertical ridge dimension changes as compared with other grafting materials or with spontaneous healing, even if they presented the worst histological outcomes. Allografts and other materials or combinations (AG + AP) presented similar performances while spontaneous healing ranked last.

Quantitative assessment of the jawbone quality classification: A meta-analysis study

AIM

Bone quality is evaluated using bone density for qualitative classification, a characteristic that may be delicate to evaluate. Contemporary implantology that relies on modern measurement techniques, needs a more quantitative estimate of the bone quality.

MATERIALS AND METHODS

PubMed and EMBASE databases were searched with no time restriction. Clinical and radiographic studies reporting on alveolar ridge dimensions and its parameters in different areas of the dentate and edentulous jaws were included. A meta-analysis was performed using random effect models to report a combined mean for alveolar ridge and its parameters. Meta regression statistical tests were performed in order to identify differences in those outcome parameters.

RESULTS

30 studies were included. The majority of the selected studies (total of 27) used live human subjects and CBCT to analyze alveolar ridge dimensions and its parameters. Using the combined mean obtained from the meta-analysis, a typical portrait of the alveolar ridge was constructed, and a geometrically based quantitative bone classification proposed. The quantitative classification was found to match the existing qualitative classification.

CONCLUSION

A geometry-based analysis was constructed that yields valuable insights on the bone type based on its components and on the dynamics of the dentate / edentulous states.

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.

Facial alveolar bone thickness and modifying factors of anterior maxillary teeth: a systematic review and meta-analysis of cone-beam computed tomography studies

Background

Understanding the anatomy of the facial alveolar bone (FAB), provides a prognostic tool for estimating the degree of dimensional ridge alterations after tooth extraction. This systematic review and meta-analysis aims to determine the FAB thickness and modifying factors of anterior maxillary teeth measured by CBCT scans. A secondary objective was to assess the facial distance from the cementoenamel junction (CEJ) to the bone crest.

Methods

An electronic search was made of Medline, Embase, Web of Science, Cochrane Library and Google Scholar up to December 2019. Studies that analyze and quantitatively compare FAB thickness at maxillary teeth by CBCT scans were included. The methodological quality of the included studies was appraised using the ROBINS-I tool and the overall meta-evidence certainty using the GRADE approach. A single means random-effects meta-analysis was performed to obtain the weighted mean for 95% confidence interval. A meta-regression of covariates and subgroup analysis was conducted. The nullity Q_h test and I² index for heterogeneity was estimated.

Results

2560 potentially relevant articles were recorded from which 29 studies were selected for the qualitative analysis, including 17,321 teeth. Seventeen studies considered the facial bone crest, and 12 the CEJ as a reference point for their measurements. Mean FAB thickness was ≤ 1 mm in maxillary incisors and canines (0.75–1.05 mm) and 1–2 mm in premolars. Patients over 50 years of age, females and thin gingival phenotype was associated with thinner FAB at some apico-coronal locations of maxillary incisors and canines. The geographical setting was an effect modifier that could explain up to 87% of the heterogeneity in FAB thickness, being Asian populations that showed the lowest FAB thickness values. The CEJ-bone crest distance was 2–2.5 mm in all teeth analyzed. Population over 50 years of age exhibited greater CEJ-bone crest distances, and males also showed a trend for greater distance. Evidence certainty has shown moderate quality in most analysis subsets.

Conclusions

Facial alveolar bone at anterior maxillary teeth is thin, heterogeneous in width along its apico-coronal dimensions, and increases in thickness in maxillary premolars. The CEJ-bone crest distance presented homogeneous and similar values in all teeth analyzed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01495-2.

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.

Compromised extraction sockets: a new classification and prevalence involving both soft and hard tissue loss

PURPOSE

Previous studies have solely focused on fresh extraction sockets, whereas in clinical settings, alveolar sockets are commonly associated with chronic inflammation. Because the extent of tissue destruction varies depending on the origin and the severity of inflammation, infected alveolar sockets may display various configurations of their remaining soft and hard tissues following tooth extraction. The aim of this study was to classify infected alveolar sockets and to provide the appropriate treatment approaches.

METHODS

A proposed classification of extraction sockets with chronic inflammation was developed based upon the morphology of the bone defect and soft tissue at the time of tooth extraction. The prevalence of each type of the suggested classification was determined retrospectively in a cohort of patients who underwent, between 2011 and 2015, immediate bone grafting procedures (ridge preservation/augmentation) after tooth extractions at Seoul National University Dental Hospital.

RESULTS

The extraction sockets were classified into 5 types: type I, type II, type III, type IV (A & B), and type V. In this system, the severity of bone and soft tissue breakdown increases from type I to type V, while the reconstruction potential and treatment predictability decrease according to the same sequence of socket types. The retrospective screening of the included extraction sites revealed that most of the sockets assigned to ridge preservation displayed features of type IV (86.87%).

CONCLUSIONS

The present article classified different types of commonly observed infected sockets based on diverse levels of ridge destruction. Type IV sockets, featuring an advanced breakdown of alveolar bone, appear to be more frequent than the other socket types.

Prosthetically Driven Alveolar Reconstructions: A Retrospective Study

This study aims to evaluate the post-extraction alveolar bone reconstruction amongst 12 patients exhibiting loss of buccal bone plate in a tooth of the anterior region of the maxilla using the prosthetically-driven alveolar reconstruction technique (PDAR). In PDAR, a partial fixed provisional prosthesis (PFPP [conventional or adhesive]) with a specially designed pontic maintains the clot in a mechanically stable position during alveolar regeneration. Moreover, the pontic design, in hourglass shape and located in the subgingival area, also prevents gingival margins from collapsing. Gingival recession was evaluated through the 6-month healing period. Cone beam computed tomography (CBCT) was performed 1 month before and 8 months after PDAR treatment. For the primary outcome, in the panoramic imaging, the central area of bone defect in each tooth was selected for linear measurements. Measurements of the vertical buccal bone gain and the gain in thickness in the alveolar bone crest were obtained 8 months after PDAR. Descriptive statistics and intraclass correlation coefficient analysis were conducted. After treatment, all patients showed bone formation (a mean vertical gain of 7.1±3.7 mm, associated with a horizontal mean gain of 4.5±1.4 mm in the alveolar bone crest). The intraclass correlation coefficient for the measurements performed using CBCT was 0.999. No gingival recession, greater than 1 mm, was observed. Lower-morbidity procedures without the use of biomaterials may be a useful in post-extraction alveolar ridge regeneration and/or preservation. PDAR promoted alveolar bone formation without flaps, grafts and membranes.

Post-extraction dimensional changes: A systematic review and meta-analysis

AIM

To analyse the evidence pertaining to post-extraction dimensional changes in the alveolar ridge after unassisted socket healing.

MATERIALS AND METHODS

The protocol of this PRISMA-compliant systematic review (SRs) was registered in PROSPERO (CRD42020178857). A literature search to identify studies that fulfilled the eligibility criteria was conducted. Data of interest were extracted. Qualitative and random-effects meta-analyses were performed if at least two studies with comparable features and variables reported the same outcome of interest.

RESULTS

Twenty-eight articles were selected, of which 20 could be utilized for the conduction of quantitative analyses by method of assessment (i.e. clinical vs radiographic measurements) and location (i.e. non-molar vs molar sites). Pooled estimates revealed that mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed clinically in non-molar sites was 2.73 mm (95% CI: 2.36-3.11), 1.71 mm (95% CI: 1.30-2.12) and 1.44 mm (95% CI: 0.78-2.10), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in non-molar sites was 2.54 mm (95% CI: 1.97-3.11), 1.65 mm (95% CI: 0.42-2.88) and 0.87 mm (95% CI: 0.36-1.38), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in molar sites was 3.61 mm (95% CI: 3.24-3.98), 1.46 mm (95% CI: 0.73-2.20) and 1.20 mm (95% CI: 0.56-1.83), respectively.

CONCLUSION

A variable amount of alveolar bone resorption occurs after unassisted socket healing depending on tooth type.

Three-dimensional analysis of dimensional changes after alveolar ridge preservation with bone substitutes or plasma rich in growth factors: Randomized and controlled clinical trial

OBJECTIVES

To evaluate alveolar ridge dimensional changes of different alveolar ridge preservation techniques after 3 months of tooth extraction and to compare the efficacy of autologous plasma rich in growth factor (PRGF) to the bone substitutes in alveolar ridge preservation and sites left to heal spontaneously.

MATERIALS AND METHODS

Forty patients requiring tooth extraction in the anterior maxilla were randomly allocated to the four following treatment modalities: spontaneous healing (control), natural bovine bone mineral covered with resorbable native collagen membrane (BBM/CM), freeze-dried bone allograft covered with resorbable native collagen membrane (FDBA/CM) and PRGF alone. Cone beam computed tomography (CBCT) scans were taken after surgery and 3 months later. The measurements of height and width (at 1, 3, and 5 mm below the crest) were performed after superimposing the 2 consecutive CBCT scans.

RESULTS

The greatest horizontal alveolar bone resorption at 1 mm below bone crest was observed in the control group (-1.61 ± 1.76 mm, P = .037), whereas the least reduction in width was found in the BBM/CM group (-0.68 ± 0.67 mm, P = .037). The most pronounced alveolar height reduction was observed in the control group (-0.86 ± 0.43 mm), whereas alveolar ridge preservation with BBMC/CM (-0.26 ± 0.91 mm) and PRGF (-0.54 ± 0.86 mm) successfully reduced the alveolar height reduction as compared to the control group.

CONCLUSIONS

Alveolar ridge preservation technique in the esthetic zone using BBM/CM or using PRGF is beneficial to reduce horizontal and vertical bone changes.

The fate of the distal papilla around tooth-bound implant-supported restorations in maxillary central incisor sites

The distal papilla around tooth-bound implant-supported restorations in maxillary central incisor sites tends to exhibit an atrophied aspect after tissue maturation following the delivery of the final prosthesis. This article provides an explanation to this phenomenon, as well as a set of therapeutic considerations to minimize its occurrence and optimize the outcomes of tooth replacement therapy with dental implants in this specific anatomic location.

The "One Piece" Autologous Tuberosity Graft: A Contemporary Concept in Ridge Preservation

Tooth extraction causes major changes to the ridge, rendering implant placement a more challenging procedure. Proper management of the socket is necessary to ensure sufficient bone and soft tissue for a successful implant-supported prosthesis. This article presents a practical approach for autologous hard and soft tissue grafting. A soft and hard tissue graft is harvested in one piece from the maxillary tuberosity and stabilized in the extraction socket.

Efficacy of Alveolar Ridge Preservation: A Randomized Controlled Trial

Alveolar ridge preservation (ARP) therapy is indicated to attenuate the physiologic resorptive events that occur as a consequence of tooth extraction with the purpose of facilitating tooth replacement therapy. This randomized controlled trial was primarily aimed at testing the efficacy of ARP as compared with unassisted socket healing. A secondary objective was to evaluate the effect that local phenotypic factors play in the volumetric reduction of the alveolar bone. A total of 53 subjects completed the study. Subjects were randomized into either the control group, which involved only tooth extraction (EXT n = 27), or the experimental group, which received ARP using a combination of socket grafting with a particulate bone allograft and socket sealing with a nonabsorbable membrane (dPTFE) following tooth extraction (ARP n = 26). A set of clinical, linear, volumetric, implant-related, and patient-reported outcomes were assessed during a 14-wk healing period. All linear bone assessments (horizontal, midbuccal, and midlingual reduction) revealed that ARP is superior to EXT. Likewise, volumetric bone resorption was significantly higher in the control group (mean ± SD: EXT = −15.83% ± 4.48%, ARP = −8.36% ± 3.81%, P < 0.0001). Linear regression analyses revealed that baseline buccal bone thickness is a strong predictor of alveolar bone resorption in both groups. Interestingly, no significant differences in terms of soft tissue contour change were observed between groups. Additional bone augmentation to facilitate implant placement in a prosthetically acceptable position was deemed necessary in 48.1% of the EXT sites and only 11.5% of the ARP sites ( P < 0.004). Assessment of perceived postoperative discomfort at each follow-up visit revealed a progressive decrease over time, which was comparable between groups. Although some extent of alveolar ridge remodeling occurred in both groups, ARP therapy was superior to EXT as it was more efficacious in the maintenance of alveolar bone and reduced the estimated need for additional bone augmentation at the time of implant placement (ClinicalTrials.gov NCT01794806).

Deproteinized bovine bone mineral is non-inferior to deproteinized bovine bone mineral with 10% collagen in maintaining the soft tissue contour post-extraction: A randomized trial

OBJECTIVES

To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to demineralized bovine bone mineral with 10% collagen (DBBM-C) for the maintenance of the soft tissue contour after tooth extraction in the esthetic zone.

MATERIAL AND METHODS

Sixty-five patients randomly received ridge preservation at a single site in the anterior maxilla with DBBM or DBBM-C. Both, DBBM and DBBM-C, were covered with a collagen matrix. Profilometric analyses were performed at baseline (BL), immediately after treatment (PO), and at 4 months (FU; day of implant placement). The main outcome was the horizontal mean change (HC) at the buccal aspect. The measurements also included changes of the estimated soft tissue thickness (eTT) at 1, 3, and 5 mm below the buccal gingival margin. Descriptive analysis was performed, and differences between groups were analyzed using independent samples t test. The non-inferiority test was performed for HC.

RESULTS

At 4 months, the horizontal mean change (HC) was -1.43 mm (±0.53 mm) (DBBM-C) and -1.32 mm (±0.53 mm) (DBBM). Change of the estimated soft tissue thickness (eTT) between baseline (BL) and four months of follow-up (FU) at 1, 3, and 5 mm amounted to -4.58 mm (±2.02 mm), -2.40 mm (±0.97 mm), and -1.37 mm (±0.78 mm) for DBBM-C and to -4.12 mm (±1.80 mm), -2.09 mm (±0.91 mm), and -1.23 mm (±0.72 mm) for DBBM. The differences between the groups were not statistically significantly for any of the outcome measures (p > .05).

CONCLUSIONS

DBBM is non-inferior to DBBM-C for the maintenance of the soft tissue contour 4 months after tooth extraction.

Effect of alveolar ridge preservation interventions following tooth extraction: A systematic review and meta-analysis

AIM

The aim of this systematic review was to critically analyse the available evidence on the effect of different modalities of alveolar ridge preservation (ARP) as compared to tooth extraction alone in function of relevant clinical, radiographic and patient-centred outcomes.

MATERIAL AND METHODS

A comprehensive search aimed at identifying pertinent literature for the purpose of this review was conducted by two independent examiners. Only randomized clinical trials (RCTs) that met the eligibility criteria were selected. Relevant data from these RCTs were collated into evidence tables. Endpoints of interest included clinical, radiographic and patient-reported outcome measures (PROMs). Interventions reported in the selected studies were clustered into ARP treatment modalities. All these different ARP modalities were compared to the control therapy (i.e. spontaneous socket healing) in each individual study after a 3- to 6-month healing period. Random-effects meta-analyses were conducted if at least two studies within the same ARP treatment modality reported on the same outcome of interest.

RESULTS

A combined database, grey literature and hand search identified 3,003 records, of which 1,789 were screened after removal of duplicates. Following the application of the eligibility criteria, 25 articles for a total of 22 RCTs were included in the final selection, from which nine different ARP treatment modalities were identified: (a) bovine bone particles (BBP) + socket sealing (SS), (b) construct made of 90% bovine bone granules and 10% porcine collagen (BBG/PC) + SS, (c) cortico-cancellous porcine bone particles (CPBP) + SS, (d) allograft particles (AG) + SS, (e) alloplastic material (AP) with or without SS, (f) autologous blood-derived products (ABDP), (g) cell therapy (CTh), (h) recombinant morphogenic protein-2 (rhBMP-2) and (i) SS alone. Quantitative analyses for different ARP modalities, all of which involved socket grafting with a bone substitute, were feasible for a subset of clinical and radiographic outcomes. The results of a pooled quantitative analysis revealed that ARP via socket grafting (ARP-SG), as compared to tooth extraction alone, prevents horizontal (M = 1.99 mm; 95% CI 1.54-2.44; p < 0.00001), vertical mid-buccal (M = 1.72 mm; 95% CI 0.96-2.48; p < 0.00001) and vertical mid-lingual (M = 1.16 mm; 95% CI 0.81-1.52; p < 0.00001) bone resorption. Whether there is a superior ARP or SS approach could not be determined on the basis of the selected evidence. However, the application of particulate xenogenic or allogenic materials covered with an absorbable collagen membrane or a rapidly absorbable collagen sponge was associated with the most favourable outcomes in terms of horizontal ridge preservation. A specific quantitative analysis showed that sites presenting a buccal bone thickness >1.0 mm exhibited more favourable ridge preservation outcomes (difference between ARP [AG + SS] and control = 3.2 mm), as compared to sites with a thinner buccal wall (difference between ARP [AG + SS] and control = 1.29 mm). The effect of other local and systemic factors could not be assessed as part of the quantitative analyses. PROMs were comparable between the experimental and the control group in two studies involving the use of ABDP. The effect of other ARP modalities on PROMs could not be investigated, as these outcomes were not reported in any other clinical trial included in this study.

CONCLUSION

Alveolar ridge preservation is an effective therapy to attenuate the dimensional reduction of the alveolar ridge that normally takes place after tooth extraction.

Histomorphometric evaluation of different grafting materials used for alveolar ridge preservation: a systematic review and network meta-analysis

In this systematic review and network meta-analysis including only randomized clinical trials (RCTs), different grafting materials used in alveolar ridge preservation after tooth extraction were analysed, focusing on histomorphometric new bone formation (NBF) in core biopsies obtained during implant placement. The PubMed, Embase, Cochrane Library, Web of Science, Scopus, and LILACS databases, as well as the grey literature, were searched for published and unpublished trials (from database inception to January 14, 2019). The primary outcome was the percentage of NBF. The secondary outcomes were the percentage of residual biomaterial and the percentage of soft tissue. An arm-based network meta-analysis was performed. The rank of intervention efficacy was obtained to measure the probability of each biomaterial being ranked first across all interventions. A total of 1526 studies were found, of which 38 were included for quantitative analysis. Three trials were rated as having a high risk of bias and 35 trials as having an unclear risk of bias. The network meta-analysis showed that nine grafting materials decreased NBF and 25 did not decrease NBF. The grafting material with the highest amount of NBF was plasma rich in growth factors. Due to the lack of studies with a low risk of bias, further RCTs are needed for definitive conclusions.

Comparison between two bone substitutes for alveolar ridge preservation after tooth extraction: Cone-beam computed tomography results of a non-inferiority randomized controlled trial

AIM

To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to DBBM with 10% collagen (DBBM-C) for maintenance of bone volume after tooth extraction in the anterior maxilla.

MATERIALS AND METHODS

Sixty-six patients were randomly treated with DBBM or DBBM-C, both of which were covered with a collagen matrix for ridge preservation in the anterior maxilla. Cone-beam computed tomographic analysis was performed immediately and 4 months after treatment. The primary outcome, for which non-inferiority of DBBM was tested, was change in the horizontal ridge width 1 mm below the buccal alveolar crest (HW-1) 4 months after extraction.

RESULTS

Four months after extraction, HW-1 measured -1.60 mm ± 0.82 mm for DBBM-C, while the DBBM group showed a mean loss of -1.37 mm ± 0.84 mm (p = 0.28, 0.23 [95% CI: -0.19; 0.64]). The horizontal ridge width at 3 mm (HW-3) showed -0.98 mm (±0.67 mm) for DBBM-C and -0.84 mm (±0.62 mm) for DBBM (p = 0.40, 0.12 [95% CI: -0.19; 0.45]), and the horizontal ridge width at 5 mm (HW-5) showed -0.67 mm (±0.47 mm) for DBBM-C and -0.56 mm (±0.48 mm) for DBBM (p = 0.36, 0.11 [95% CI: -0.13; 0.34]).

CONCLUSIONS

The present clinical trial demonstrated non-inferiority of DBBM compared to DBBM-C for maintenance of alveolar bone volume 4 months after tooth extraction in the anterior maxilla.

Osseous Remodeling Around Dental Implants

Adequate bone remodeling may be a primary parameter for long-term successful complication-free dental implant treatment. A 1.8-mm osseous thickness around dental implants is thought to be the minimum thickness for adequate vasculature for osteocyte nutrition and function. A dental implant does not provide progenitor cells or angiogenic or osteogenic factors. Thus, the surrounding bone may need to have a 1.8-mm thickness to accommodate the vasculature necessary for nutrients for appropriate remodeling. Additionally, the 1.8-mm dimension may provide for mechanical load resistance. There is no evidence to illustrate the physiologic need for the 1.8-mm dimension. This dimension requirement is based on clinical outcome observations. Basic science research for bone survival around dental implants is needed.

[Recent research advances on alveolar ridge preservation after tooth extraction]

Resorption of alveolar bone that occurs following tooth extraction is irreversible, it may compromise the restoration of implants or conventional prostheses. Ridge preservation can minimize ridge resorption after tooth extraction. In this article, healing features of socket after tooth extraction, factors influencing ridge remodeling, and the use of bioma-terials were reviewed.

Synthetic polymeric barrier membrane associated with blood coagulum, human allograft, or bovine bone substitute for ridge preservation: a randomized, controlled, clinical and histological trial

During the normal healing process, an extraction site may lose significant bone volume, making implant placement problematic. Quantitative evaluations of the amount of bone maintained by socket preservation with various materials are limited. The objective of this study was to evaluate, both clinically and histologically, the extent of alveolar bone preservation by blood coagulum (BC) and the potential additional benefits of bone allograft material (AL) versus the state-of-the-art bovine bone mineral (BB), covered by a polyethylene glycol (PEG) barrier, in extraction socket grafting procedures. Adult patients (n=32) with single-rooted teeth indicated for extraction were treated (45 sites). After atraumatic extraction, the sockets were filled with BC, AL, or BB and covered with a synthetic PEG barrier membrane. Changes in bone height and width were measured clinically and the amount of bone formed and residual graft particles were measured histologically after 6 months. Changes in ridge width at 6 months were -1.5mm for AL versus -2.5mm for BB and -2.3mm for BC. New bone formation amounted to 47.8%, 33.3%, and 28.2% at BC-, AL-, and BB-treated sites, respectively. Using AL with the PEG barrier preserved the ridge width at 6 months better than BB or BC and resulted in similar amounts of bone histologically to BB.

Efficacy of Alveolar Ridge Preservation after Maxillary Molar Extraction in Reducing Crestal Bone Resorption and Sinus Pneumatization: A Multicenter Prospective Case-Control Study

Aim

To evaluate, with three-dimensional analysis, the effectiveness of alveolar ridge preservation (ARP) after maxillary molar extraction in reducing alveolar bone resorption and maxillary sinus pneumatization when compared to unassisted socket healing.

Methods

Patients were included in the study following inclusion criteria and underwent minimally traumatic maxillary molar extraction followed by ARP using synthetic nanohydroxyapatite (Fisiograft Bone, Ghimas, Italy) (test group) or unassisted socket healing (control group). Cone-beam computerized tomographies (CBCT) were performed immediately after tooth extraction (T0) and 6 months postoperatively (T1). CBCTs were superimposed by using a specific software (Amira, Thermo Fisher Scientific, USA) and the following items were analyzed in both groups: (i) postextractive maxillary sinus floor expansion in coronal direction and (ii) postextractive alveolar bone dimensional changes (both vertical and horizontal). All data were tested for normality and equality of variance and subsequently analyzed by independent samples T-test and Mann–Whitney test.

Results

Thirty patients were treated by three centers and twenty-six (test n=13; control n=13) were included in the final analysis. Mean sinus pneumatization at T1 was 0.69±0.48 mm in the test group and 1.04±0.67 mm in the control group (p=0.15). Mean vertical reduction of the alveolar bone at T1 was 1.62±0.49 mm in the test group and 2.01±0.84 mm in the control group (p=0.08). Mean horizontal resorption of crestal bone at T1 was 2.73±1.68 mm in test group and 3.63±2.24 mm in control group (p=0.24).

Conclusions

It could be suggested that ARP performed after maxillary molar extraction may reduce the entity of sinus pneumatization and alveolar bone resorption, compared to unassisted socket healing. This technique could decrease the necessity of advanced regenerative procedures prior to dental implant placement in posterior maxilla.

Rehabilitation of Postextractive Socket in the Premaxilla: A 12-Year Study on 27 Titanium Plasma Spray Resorbable Calcium Phosphate Coated Single Implants

OBJECTIVES

The purpose of this study was to evaluate the peri-implant bone tissue level on postextractive resorbable calcium phosphate coated single implants placed in premaxillary sites grafted with autologous bone, anorganic bovine bone (ABB), platelet-rich plasma (PRP), and keratinized epithelial connective graft over 12 years.

MATERIALS AND METHODS

A total of 27 patients received a postextractive single implant in premaxillary sites grafted with ABB and PRP. Two months later, a keratinized epithelial connective graft was applied and the implants loaded. Clinical and radiographical evaluations were performed at baseline, 6 and 18 months, 4 and 6 years after the implant insertion, and then every 2 years up to the 12th year.

RESULTS

After 12 years, a total of 22 implants (81.48%), were available for the final data analysis; the implants achieved a 100% cumulative survival rate, and only a mild degree of periodontal tissue inflammation was recorded. The radiographic evaluation revealed a physiological marginal bone remodeling over the follow-up.

CONCLUSION

Although a good preservation of the residual bone tissue in postextraction implant sites treated with keratinized epithelial connective tissue grafts was observed, the low number of treated cases does not allow us to propose this experimental protocol to all cases of bone defects but it certainly represents a new option. Further studies on a greater number of patients and using implants with different surface characteristics should be conducted for a better understanding of the indications of the proposed treatment.

Effect of flapless ridge preservation with two different alloplastic materials in sockets with buccal dehiscence defects-volumetric and linear changes

OBJECTIVE

To test whether or not one out of two alloplastic materials used for ridge preservation (RP) is superior to the other in terms of volumetric and linear ridge changes over time.

MATERIALS AND METHODS

In 16 adult beagle dogs, the distal roots of P3 and P4 were extracted and 50% of the buccal bone plate removed. Ridge preservation was performed randomly using two different alloplastic bone grafting substitutes (poly lactic-co-glycolic acid (PLGA) coated biphasic calcium phosphate particles consisting of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (ß-TCP=test 1), (a biphasic calcium phosphate consisting 60% HA and 40% ß-TCP=test 2) and a resorbable collagen membrane or a control group (sham). Sacrifice was performed at three time-points (4, 8, 16 weeks later). Impressions were taken before extraction, after RP, and at sacrifice, allowing for assessment of volumetric changes. A multi-way ANOVA was computed, and partial Type-II F tests were performed.

RESULTS

Both ridge preservation procedures minimized the volume loss compared to spontaneous healing. The median buccal volume changes between pre-extraction and sacrifice were - 1.76 mm (Q1 = - 2.56; Q3 = - 1.42) for test 1, - 1.62 mm (Q1 = - 2.06; Q3 = - 1.38) for test 2, and - 2.42 mm (Q1 = - 2.63; Q3 = - 2.03) for control. The mean ridge width measurements did not show statistically significant differences between test 1 (- 2.51 mm; Q1 = - 3.25; Q3 = - 1.70) and test 2 (- 2.04 mm; Q1 = - 3.82; Q3 = - 1.81) (p = 0.813), but between test and control (- 3.85 mm; Q1 = - 5.02; Q3 = - 3.27) (p = 0.003).

CONCLUSIONS

Both RP techniques were successful in maintaining the buccal contour from pre-extraction to sacrifice to a similar extent and more favorable compared to spontaneous healing.

CLINICAL RELEVANCE

Alloplastic materials can successfully be used for RP procedures.

Efficacy of collagen matrix seal and collagen sponge on ridge preservation in combination with bone allograft: A randomized controlled clinical trial

AIM

To test whether the use of collagen matrix seal (CMS) results in similar hard and soft tissue remodelling to that with collagen sponge (CS) used as barriers 4 months following alveolar ridge preservation (ARP), in combination with freeze-dried bone allograft (FDBA).

MATERIALS AND METHODS

Twenty-eight patients were randomly assigned to the two groups. Clinical and radiographic measurements were recorded with the same stent at baseline and 4 months for standardization. The flapless technique following a traumatic extraction was used for the two types of barriers.

RESULTS

All patients completed the study, 14 in the CMS group and 14 in the CS group. Reduction in coronal ridge width (1.21 mm-14.91% CMS and 1.47 mm-20.40% CS) and vertical buccal bone resorption (0.30 mm CMS and 0.79 mm CS) were not significantly different. A slight increase in buccal gingival thickness at the coronal part was observed in both groups (0.9 mm CMS and 0.5 mm CS).

CONCLUSIONS

Collagen matrix seal and CS, when combined with FDBA, significantly minimized ridge resorption in all dimensions and maintained buccal soft tissue thickness in sockets with a buccal plate loss of <2 mm in comparison to previously reported findings recorded after tooth extraction without ARP.

Case Selection is Critical for Successful Outcomes Following Immediate Implant Placement in the Esthetic Zone

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Immediate versus delayed implant placement after anterior single tooth extraction: the timing randomized controlled clinical trial. Tonetti MS, Cortellini P, Graziani F, Cairo F, Lang NP, Abundo R, Conforti GP, Marquardt S, Rasperini G, Silvestri M, Wallkamm B, Wetzel A. Journal of Clinical Periodontology 2017;44(2):215-24.

SOURCE OF FUNDING

Nonprofit, Foundations: European Research Group on Periodontology, Genova, Italy Industry: Thommen Medical AG, Switzerland and Geistlich AG, Switzerland (biomaterials).

TYPE OF STUDY/DESIGN

Randomized controlled trial.

Effect of ridge preservation for early implant placement - is there a need to remove the biomaterial?

AIM

To assess (i) bone regeneration around implants placed early in sites with or without ridge preservation and (ii) if the bone substitute material (DBBM-C) has to be removed at implant placement.

MATERIALS AND METHODS

In eight beagle dogs, three sites were randomly assigned to ridge preservation (DBBM-C plus collagen matrix (CMX)) (two sites; RP) or spontaneous healing (1 site; SH). Four weeks later, in one of the RP sites, dental implants were placed without removing the DBBM-C (RP1), whereas in RP2 and SH sites all non-integrated DBBM-C and/or granulation tissue were removed before implant placement and concomitant GBR. Histomorphometric outcomes were assessed at 4 and 12 weeks.

RESULTS

The median buccal fBIC (first bone-to-implant contact) was located more apical in groups RP1: 1.34 mm (0.09; 2.96) and RP2: 1.41 mm (0.54; 2.72) than in group SH: 0.79 mm (0.26; 1.50) (p = 0.452) at 4 weeks. At 12 weeks, median buccal fBIC values were for RP1: 0.88 mm (0.00; 2.33), for RP2: 0.16 mm (0.00; 1.33) and for SH: 0.00 mm (0.00; 0.98) (p = 0.362). BIC values increased over 12 weeks in all groups.

CONCLUSIONS

Ridge preservation followed by early implant placement led to higher BIC values at 12 than at 4 weeks. There is no need to remove the biomaterial at implant placement to ensure osseointegration. No relevant differences were observed between the three groups for any outcome measure.

Clinical and Histological changes after ridge preservation with two xenografts: preliminary results from a multicentre randomized controlled clinical trial

OBJECTIVES

To evaluate and compare clinical and histological changes after ridge preservation procedures with those of spontaneous healing.

MATERIALS AND METHODS

Ninety patients were enrolled in the present randomized controlled clinical trial and underwent single-tooth extraction in the premolar/molar areas. Thirty sites were grafted with collagenated cortico-cancellous (coll), 30 sites with cortical (cort) porcine bone and 30 sites underwent natural healing. Primary (vertical and horizontal bone changes after 3 months) and secondary outcomes (histomorphometric after 3 months) were evaluated at implant placement.

RESULTS

The vertical bone changes at the grafted sockets were significantly (p < 0.0001) lower (0.30 mm for cort group and 0.57 mm for coll group) when compared to non-grafted sockets (2.10 mm for nat group). Moreover, the width reduction of the coll (0.93 mm) and cort (1.33 mm) groups was significantly lower (p < 0.0001) than the non-grafted group (3.60 mm). The analysis of subgroups attested that when premolar and molar sites were compared, the buccal bone loss appeared to be dependent both on tooth position and grafting material employed.

CONCLUSION

The ridge preservation procedures had significantly better outcomes when compared to natural healing. The biomaterials did not differ for maintenance of bone width; even though, the bone height seemed to be better preserved with the cortical porcine bone.

Guided "sandwich" technique: a novel surgical approach for safe osteotomies in the treatment of vertical bone defects in the posterior atrophic mandible: a case report

PURPOSE

A novel technique to perform safe osteotomies during inlay block regenerative procedures in the posterior atrophic mandible is described.

MATERIAL AND METHODS

A 52-year-old male patient with vertical atrophy of the left posterior mandible was treated adopting an inlay block "sandwich" technique using an allogenic cancelous block and a mixture of mineralized and demineralized human bone allograft in putty form as graft. The horizontal osteotomy for the lifting of the osteotomized bone segment was performed using a template prepared from a virtual anatomical replica of the patient's mandible obtained from cone beam computed tomography data. In the second surgical phase, 3 months after the augmentation, 2 implants were easily placed.

RESULTS

The horizontal osteotomy was carried out, with no risk, very close to the nerve structures after the precise osteotomy line established preoperatively on the three-dimensional computed tomography (3D-CT) virtual reconstruction. No neurological complications were observed in the first days after the procedure, and no subsequent problems were recorded during the 3-month healing period.

CONCLUSION

Radiographic evaluations and complication-free clinical healing demonstrate the effectiveness of this technique to obtain safe and precise osteotomies.

Histomorphometric results in ridge preservation procedures comparing various graft materials in extraction sockets with nongrafted sockets in humans: a systematic review

INTRODUCTION

The aim of this systematic review was to evaluate, from a histological point of view, the amount of newly formed bone in ridge preservation procedures using various graft materials in comparison with natural healing (NH) and to determine which is the ideal type of graft to be used.

MATERIALS AND METHODS

A search strategy was developed to find articles in a human model published between 1990 and January 2013 in English language using MEDLINE database.

RESULTS

Thirty-four articles were included in this systematic review. When comparing the percentage of newly formed bone using various grafting materials with NH, calcium sulfate, magnesium enriched hydroxyapatite, and porcine-derived bone grafts offered the best outcomes. However, due to the heterogeneity of the included studies, the search was extended to determine which type of graft resulted in greatest bone formation.

CONCLUSION

When comparing ridge preservation with NH, only 3 studies encountered a greater amount of newly formed bone in the ridge preservation group, whereas the rest did not find statistically significant differences or even observed a greater percentage of newly formed bone in the control group. Therefore, more studies are needed to determine whether the use of graft materials enhances new bone formation in contrast to NH alone and to determine the most effective bone grafting material.

Does ridge preservation following tooth extraction improve implant treatment outcomes: a systematic review: Group 4: Therapeutic concepts & methods

OBJECTIVE

(1) Primary focused question (Q1): to evaluate the effect of alveolar ridge preservation (ARP) on implant outcomes (implant placement feasibility, need for further augmentation, survival/success rates, marginal bone loss) compared with unassisted socket healing (USH) and (2) secondary focused question (Q2): to estimate the size effects (SE) of these outcomes in three different interventions (GBR, socket filler, socket seal).

MATERIAL AND METHODS

Electronic (MEDLINE, EMBASE, Cochrane Central Register LILACS; Web of Science) and hand search was conducted up to July 2014. Randomised controlled trials (RCT), controlled clinical trials (CCT) and prospective cohort studies with USH as controls were eligible in the analysis for Q1. RCTs, CCTs and prospective case series, with or without USH as control, were eligible for Q2.

RESULTS

Ten (8 RCTs, 2 CCTs) and 30 studies (21 RCTs, 7 CCTs, 2 case series) were included in the analysis for Q1 and Q2, respectively. The risk for bias was unclear or high in most of them. Q1: Implant placement was feasible in ARP-treated and USH sites. These implants presented similar survival/success rates and marginal bone levels. The need for further augmentation decreased when ARP was performed (Relative risk: 0.15, 95% CI: 0.07-0.3). Q2: The SE for implant placement feasibility was 98.5% (95% CI: 96.4-99.6) in GBR and 96.2 (95% CI: 93.1-98.2) in socket filler group. The SE for need for further augmentation was 11.9 (95% CI: 5.6-19.9) for GBR and 13.7% (95% CI: 5.0-25.6) for socket filler groups. GBR and socket filler presented similar SE for survival/success rates and average marginal bone loss. Limited data were available for implant-related outcomes in sites treated with socket seal.

CONCLUSIONS

There is limited evidence to support the clinical benefit of ARP over USH in improving implant-related outcomes despite a decrease in the need for further ridge augmentation during implant placement. Similar implant placement feasibility, survival/success rates and marginal bone loss should be anticipated following ARP or USH. Currently, it is not clear which type of ARP intervention has a superior impact on implant outcomes.

Influence of periodontal tissue thickness on buccal plate remodelling on immediate implants with xenograft

AIM

To evaluate the influence of gingival thickness and bone grafting on buccal bone plate remodelling after immediate implant placement in sockets with thin buccal bone, using a flapless approach.

MATERIALS AND METHODS

The gingiva of eight dogs was thinned at one side of the mandible, mandibular premolars were extracted without flaps, and four implants were installed on each side at 1.5 mm from the buccal bone. The sites were randomly assigned into: TG (test group) = thin gingiva; TG + GM (TG with grafting material); CG (control group) = normal gingiva; and CG + GM (CG with grafting material). After 12 weeks the dogs were sacrificed and the samples were processed for histological analysis.

RESULTS

All animals exhibited a thin buccal bone initially. In all the experimental groups the buccal gap was filled with newly formed bone and the buccal bone level was slightly apical to the implant shoulder. There were no statistically significant differences among the groups for the histomorphometric parameters.

CONCLUSIONS

The thickness of the buccal bone was a fundamental factor in buccal bone plate resorption, even with flapless implantation. The gingival thickness or the addition of a biomaterial in the gap did not influence the results.

Piezosurgical treatment of crestal bone: quantitative comparison of post-extractive socket outcomes with those of traditional treatment

OBJECTIVE

The study aimed to quantitatively compare, for the first time, the clinical outcomes of crestal bone volume resorption in sockets undergoing traditional extraction technique (TET) or piezosurgical extraction technique (PET), also considering the influence of buccal plate thickness.

MATERIAL AND METHODS

In this prospective study, 19 sockets were randomly treated with TET, and 18 sockets were randomly treated with PET. Furthermore, patients were split into subgroup A, with buccal bone plate thickness (BPT) ≤1 mm, and subgroup B, with BPT>1 mm. Buccal (BCH) and palatal (PCH) cortex height, bucco-palatal ridge (BPR) width were monitored at tooth extraction and after the 4-month post-extractive period of natural healing.

RESULTS

After 4 months, BCH, PCH and BPR width decreased more in the TET than in the PET group, but only the BPR decrease was statistically significant (P = 0.034) after ANOVA test. In both TET and PET groups, all B subgroup patients showed a lower decrease than A subgroup patients for both BCH, PCH and BPR, statistically significant for PCH (P = 0.019) and BPR (P < 0.001) of TET group, and BPR (P = 0.002) of PET group, after ANOVA. Both A and B subgroups of PET showed a statistically significant lower decrease than the corresponding subgroups of TET, comparing A (P = 0.005) and B (P = 0.037) subgroups for BPR, after ANOVA.

CONCLUSIONS

With both thin and thick buccal plates, the piezosurgical extraction technique of teeth significantly decreases the horizontal resorption of the hard tissue ridge, but not the vertical resorption. Moreover, buccal plate thickness seems to be a key factor in post-extractive bone resorption: the thinner the buccal plate the greater the horizontal crestal bone loss.