A systematic review of post-extractional alveolar hard and soft tissue dimensional changes in humans

Quality assessment of systematic reviews on alveolar ridge preservation

BACKGROUND

The authors conducted a study to assess the quality of systematic reviews (SRs) published on the topic of alveolar ridge preservation (ARP).

TYPES OF STUDIES REVIEWED

The authors conducted a search for SRs on ARP on the basis of a set of eligibility criteria (only SRs involving ARP, with or without meta-analyses, written in English). The authors assessed the quality of the SRs independently of one another by using two established checklists.

RESULTS

The authors selected eight SRs. The results of all of the SRs indicated that ARP was effective in preserving the ridge volume as compared with extraction alone, but it did not fully prevent bone-resorptive events. None of the SRs, however, received the highest possible score in either of the checklists. One SR that had a score of 5 (of a possible 11) using one checklist and 5 (of a possible 14) using the other checklist had the lowest overall score. The results of this assessment revealed that a significant proportion of the investigators in the SRs did not include non-English language articles, perform hand searching of published literature or evaluate the gray literature. Assessment of publication bias and reporting of conflicts of interest also was lacking in some studies. Practical Implications. Although ARP appears to be an effective approach to preventing resorption after tooth extraction, significant structural and methodological variability exists among SRs on this topic. Future SRs on ARP should consider the use of quality assessment checklists to minimize methodological shortcomings for better dissemination of scientific evidence.

2-Dimensional changes of the soft tissue profile of augmented and non-augmented human extraction sockets: a randomized pilot study

AIM

This study identified the soft tissue changes of the alveolar ridge at different time points within 12 weeks after tooth extraction with and without socket augmentation.

MATERIALS AND METHODS

In 38 patients with single tooth extractions, 40 sockets were augmented and 39 extraction sockets were not augmented. At 2, 4, 6, 8 and 12 weeks impressions were taken and casts digitized with a laser scanner. The horizontal and vertical changes were compared between augmented and non-augmented sites. A p-value <0.05 was considered statistically significant.

RESULTS

The mean changes of augmented sockets were between 0.4 mm (2 weeks) and 0.8 mm (12 weeks). In non-augmented sockets changes of 0.7 mm (2 weeks) and of 1.0 mm (12 weeks) were demonstrated. The mean values differed significantly between the buccal and oral region (p < 0.01). Overall, there were significant differences of the mean dimensional changes regarding time (p < 0.01) and augmentation (p < 0.01).

CONCLUSIONS

Augmented sockets showed less resorption within 4 weeks after extraction compared to non-augmented sockets. Non-augmented sockets showed a continuous dimensional loss with a great variation over 12 weeks whereas augmented sockets had the highest degree of resorption between 4 and 6 weeks. At 12 weeks a comparable resorption in augmented and non-augmented sockets was observed.

Accurate registration of peri-implant soft tissues to create an optimal emergence profile

One of the challenges in restoring anterior space with implant restoration is maintaining the natural looking of peri-implant area. This case report presents a clinical procedure to create the soft tissue emergence profile for anterior maxillary teeth. A 49-year-old male presented with missing right maxillary lateral incisor. A provisional restoration was inserted 1 week after implant placement. Area of the provisional restoration related to the gingival tissue (transmucosal area) was adjusted to create an optimum emergence profile. Two months later, an indirect method was used to accurately transfer the soft peri-implant tissues to the master cast. This clinical technique minimizes surgical procedure and avoids the possibility of soft tissue collapsing that may occur during the impression procedure.

Buccolingual implant position and vertical abutment finish line geometry: two strictly related factors that may influence the implant esthetic outcome

PURPOSE

Three-dimensional implant positioning has always been a highly debated topic especially in the esthetic zone due to many problems related to buccal bone resorption. A new concept in implant position, dictated by changing the abutment finish line, is presented in the following article.

MATERIALS AND METHODS

The actual guidelines on implant position agree that in the bucco-palatal dimension, the implant should be placed more toward the palatal preserving at least 2 mm of buccal bone. However, changing the abutment finish line geometry from horizontal to vertical, the authors' geometry of choice, the surgical approach in the bucco-palatal direction has been modified accordingly to ensure final restorations that will guarantee long-term soft tissue stability.

RESULTS

The emergence angle of the natural teeth has been the authors' guide to establish the implant position which should be located with the long axis of the implant corresponding to the incisal edge of the future restoration. Observation of the clinical results in the past years strongly supports this approach.

CONCLUSIONS

The surgical and prosthetic concepts described in this article allow the clinician to recreate a pleasant and natural-looking esthetics while the patient can easily maintain a proper hygiene around the implant. However, despite the promising clinical results obtained by the authors, further clinical and randomized researches should be realized to validate the above-proposed approach.

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.

Volumetric analysis of remodelling pattern after ridge preservation comparing use of two types of xenografts. A multicentre randomized clinical trial

OBJECTIVES

The aim of this randomized clinical trial was to analyse and compare the volumetric changes after ridge preservation procedures using two different biomaterials and to evaluate associations between outcome variables and pristine three-dimensional aspects of the ridges.

MATERIALS AND METHODS

Twenty-eight patients subjected to single-tooth alveolar ridge preservation were enrolled in the present multicentre, single-blind, prospective and randomized clinical trial. Fourteen sites were randomly allocated to each experimental group. The experimental sites were grafted with pre-hydrated collagenated cortico-cancellous porcine bone (coll group) or with a cortical porcine bone (cort group) and a collagen membrane; a secondary soft tissue healing was obtained for all experimental sites. Plaster casts were scanned (preoperative, at 1 and 3 months postoperative). Analysis of volumes and areas was performed, and all measured variables were statistically compared.

RESULTS

Intragroup analyses at 3 months revealed that when examining changes related to three-dimensional features of remodelling patterns (volume, surfaces, height and shape), the two biomaterials showed similar behaviours with a minor loss in volume and ridge surface. Intergroup analysis at 3-month survey revealed that volume resorption of the coll group (244 mm³ ) was significantly lower (P = 0.0140) than that of the cort group (349 mm³ ). The reduction for basal surface appeared significantly different between the two groups at 1-month survey only (P = 0.0137), while the final basal surface reduction was 4.9 and 12.2 mm² for coll and cort group, respectively. The superior surface reduction was 40.8 mm² for coll and 50.7 mm² for cort group, with no significant difference between the two groups.

CONCLUSION

At the 3rd month analysis, coll group showed a significantly lower reduction of ridge volume and a significantly smaller shrinkage of the basal area when compared to the cort group; moreover, the coll group experienced a smaller superior surface shrinkage when compared to the cort group, even though no significance was evaluated.

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.

Single-tooth morse taper connection implant placed in grafted site of the anterior maxilla: clinical and radiographic evaluation

The aim of this study was to achieve aesthetically pleasing soft tissue contours in a severely compromised tooth in the anterior region of the maxilla. For a right-maxillary central incisor with localized advanced chronic periodontitis a tooth extraction followed by reconstructive procedures and delayed implant placement was proposed and accepted by the patient. Guided bone regeneration (GBR) technique was employed, with a biphasic calcium-phosphate (BCP) block graft placed in the extraction socket in conjunction with granules of the same material and a resorbable barrier membrane. After 6 months of healing, an implant was installed. The acrylic provisional restoration remained in situ for 3 months and then was substituted with the definitive crown. This ridge reconstruction technique enabled preserving both hard and soft tissues and counteracting vertical and horizontal bone resorption after tooth extraction and allowed for an ideal three-dimensional implant placement. Localized severe alveolar bone resorption of the anterior maxilla associated with chronic periodontal disease can be successfully treated by means of ridge reconstruction with GBR and delayed implant insertion; the placement of an early-loaded, Morse taper connection implant in the grafted site was effective to create an excellent clinical aesthetic result and to maintain it along time.

Histologic healing following tooth extraction with ridge preservation using mineralized versus combined mineralized-demineralized freeze-dried bone allograft: a randomized controlled clinical trial

BACKGROUND

Mineralized and demineralized freeze-dried bone allografts (FDBAs) are used in alveolar ridge (AR) preservation; however, each material has advantages and disadvantages. Combinations of allografts aimed at capitalizing on the advantages each offers are available. To date, there is no evidence to indicate if a combination allograft is superior in this application. The primary objective of this study is to histologically evaluate and compare healing of non-molar extraction sites grafted with either mineralized FDBA or a 70:30 mineralized:demineralized FDBA combination allograft in AR preservation. The secondary objective is to compare dimensional changes in ridge height and width after grafting with these two materials.

METHODS

Forty-two patients randomized into two equal groups received ridge preservation with either 100% mineralized FDBA (active control group) or the combination 70% mineralized: 30% demineralized allograft (test group). Sites were allowed to heal for 18 to 20 weeks, at which time core biopsies were obtained and dental implants were placed. AR dimensions were evaluated at the time of extraction and at implant placement, including change in ridge width and change in buccal and lingual ridge height. Histomorphometric analysis was performed to determine percentage of vital bone, residual graft, and connective tissue/other non-bone components.

RESULTS

There was no significant difference between groups in AR dimensional changes. Combination allograft produced increased vital bone percentage (36.16%) compared to the FDBA group (24.69%; P = 0.0116). The combination allograft also had a significantly lower mean percentage of residual graft particles (18.24%) compared to FDBA (27.04%; P = 0.0350).

CONCLUSIONS

This study provides the first histologic evidence showing greater new bone formation with a combination mineralized/demineralized allograft compared to 100% mineralized FDBA in AR preservation in humans. Combination allograft results in increased vital bone formation while providing similar dimensional stability of the AR compared to FDBA alone in AR preservation.

Post-extraction evaluation of sockets with one plate loss--a microtomographic and histological study

AIM

The aim of this study is to evaluate the characteristics of socket repair after teeth extraction with loss of a bone plate.

MATERIAL AND METHOD

Lower incisors were extracted from 120-day-old male rabbits. A standardized defect of 5 mm in the buccal plate was created in one of the socket sites. Furthermore, complete closures of the sockets entrance were performed. Two groups of biopsies were obtained: one with 14 days of healing and the other with 112, to perform the micro-CT and histological evaluations of the tested group with plate loss comparing with the control group with the intact buccal bone wall.

RESULTS

Plate loss sites demonstrated reduction in width when compared to the intact ones and, this difference decreased with time.

CONCLUSION

Long-term analysis showed that plate loss interfered in final ridge measurements by reducing the middle portion of the socket width compared to the intact plate sockets. The histological and micro-CT qualitative analysis showed that both sites presented similar pattern of healing, despite the reduced dimension found in plate loss sites.

Statins and alveolar bone resorption: a narrative review of preclinical and clinical studies

CONTEXT

Tooth extraction and periodontal disease are both common clinical situations associated with alveolar bone loss.

OBJECTIVE

To analyze the reported results of in vivo studies investigating the effectiveness of statins to reduce alveolar bone resorption.

STUDY DESIGN

Systematic electronic search of the MEDLINE-PubMed database.

RESULTS

A total of 21 studies met the inclusion criteria. This review showed that the use of statins reduced significantly alveolar bone resorption observed during periodontal disease and after tooth extraction. Oral administration was effective using high statin concentrations, although local administration using a biodegradable carrier was effective with lower concentrations. It was recently reported that statins were effective to reduce alveolar bone loss as an adjunct to scaling and root planing (SRP) in several clinical trials. Further studies are needed to confirm these promising results.

Influence of local administration of pamidronate on extraction socket healing--a histomorphometric proof-of-principle pre-clinical in vivo evaluation

OBJECTIVES

To evaluate the influence of local administration of pamidronate histomorphometrically, adsorbed on a collagenated porcine bone substitute, on extraction socket healing.

MATERIAL AND METHODS

Two American Fox-hound dogs were used within this proof-of-principle study. Following endodontic treatment of the distal root of the three lower premolars, the teeth were hemisected, and the mesial roots were extracted flapless. The sockets were then loosely filled, in a split-mouth fashion, with a collagenated porcine bone substitute (Osteobiol Gen-Os; CPB), rehydrated either with 90 mg/ml pamidronate (Aredia(®) ; test) or with sterile saline (control). Extraction sockets were sealed with connective tissue punches obtained from the palate and secured with sutures. After 4 months of healing, specimens containing the socket sites and remaining roots were retrieved and histomorphometrically examined.

RESULTS

Histological evaluation of the sections revealed substantial differences in healing patterns. Control sites presented with various amounts of newly formed bone and no evidence of CPB inside the socket; in contrast, limited amounts of bone were observed at test sites, which were filled with CPB mainly embedded in connective tissue. Only minor differences were observed between test and control sites regarding vertical bone loss (buccal bone: -1.01 mm vs. -1.15 mm; lingual bone: -0.92 mm vs. -1.15 mm). Horizontal bone loss was nearly three times higher in control sites comparing to sites treated with pamidronate (-2.19 ± 1.81 mm vs. -0.80 ± 0.91 mm) at a level corresponding to 3 mm below the cemento-enamel junction (CEJ).

CONCLUSION

Local administration of pamidronate adsorbed on a collagenated porcine bone substitute in particulate form appeared to delay extraction socket healing, but may also reduce post-extraction dimensional changes in terms of horizontal bone width. Additionally, pamidronate appears to obstruct resorption of the porcine bone substitute.

Alterations of the bone dimension following immediate implant placement into extraction socket: systematic review and meta-analysis

AIM

This systematic review was aimed at analysing bone dimensional alterations within the first year following immediate implant placement.

MATERIALS AND METHODS

The electronic search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE from January 1980 to October 2013. Quality assessment of selected articles was performed using Cochrane Collaboration's tool or Newcastle-Ottawa scale according to the design of each study. A meta-analysis was performed to estimate bone dimensional reduction. Weighted mean differences in bone dimension between baseline and follow-up measurement were calculated. Subgroup analysis and mete-regression were conducted to evaluate the effects of different variables.

RESULTS

A total of 1348 articles were identified following the search process. Six studies were included in the present review. The weighted mean buccal horizontal bone dimensional reduction (BHDr) was 1.07 mm and buccal vertical bone dimensional reduction (BVDr) was 0.78 mm. The weighted mean palatal bone dimensional reduction was 0.62 mm horizontally (PHDr) and 0.50 mm vertically (PVDr). The initial thickness of the buccal alveolar plate (TB) of the socket was the only variable significantly correlated with BHDr and BVDr in meta-regression analysis.

CONCLUSIONS

The bone dimensions of immediate implant sites demonstrated approximately 0.5-1.0 mm reduction in vertical and horizontal aspects 4-12 months following surgery. The results should be interpreted with care because of the data heterogeneity. The correlation of the socket buccal wall thickness, and other variables, with dimensional changes of the bony ridge should be investigated further in controlled clinical trials.

Bio-Oss(®) for delayed osseointegration of implants in dogs: a histological study

We evaluated the effects of Bio-Oss® (a natural bone substitute derived from the mineral portion of bovine bone) on delayed osseointegration of implants. The bilateral third and fourth mandibular premolars of 4 adult, healthy, male and female dogs were extracted. We randomly selected 2 extraction sockets in each dog to be filled with Bio-Oss® (the experimental group); the other 2 extraction sockets, which were not treated, served as controls. Dental implants were inserted into the alveolar bone of the experimental group and the control group 3 months after insertion of the Bio-Oss®. The osteogenic activity in the bone around the implants was assessed by evaluating the histological morphology and estimating histomorphometric variables at 3 and 6 months after delayed implantation. After 3 months, Goldner's trichrome staining analysis showed that the rate of content between the bone and the implant and the mineralised area of bone around the implant were significantly higher in the experimental group (76%(9%) and 69.5% (9.6%), respectively) than those in the control group (56.1% (8.2%) and 52.8% (7.3%), respectively, p=0.003 and 0.000). However, the 2 groups did not differ significantly at 6 months. Fluorescence microscopy showed that the mean rates of mineralisation of the bony tissue around the implant in the experimental group at months 3 and 6 were 6.8 (0.4) μm and 8.4 (0.8) μm, respectively, which were significantly higher than those in the control group (p=0.000 and 0.03). These data indicate that putting Bio-Oss® into the extraction sockets can promote osseointegration after delayed implantation, and may be a promising option for clinical use.

Effects of epigallocatechin-3-gallate on the healing of extraction sockets with a periapical lesion: A pilot study in dogs

The aim of this study was to characterize the healing process of extraction sockets with a periapical lesion following immediate graft with collagenated bovine bone mineral (CBBM) soaked with epigallocatechin-3-gallate (EGCG). Following induction of periapical lesions in premolars in five dogs, treatment of extraction sockets was divided into three groups: control (no treatment) and two test groups, CBBM with or without EGCG. 3D reconstruction and superimposition of the digital images were used to measure the dimensional changes in alveolar ridge. Histologic specimen was evaluated in all groups. The horizontal ridge widths at 4-mm level were wider in both test groups (3.3 ± 1.7 mm in CBBM; 3.0 ± 1.7 mm in CBBM+EGCG) than in the control group (1.7 ± 2.4 mm). Fibrosis and limited new bone formation were observed in the apical regions of test groups; however, the extent of fibrosis was less in the CBBM+EGCG group. Within the limitations of this study, it was conjectured that adjunctive use of EGCG with CBBM can be a candidate biomaterial in grafting of extraction socket with periapical lesion. Bone regeneration at the coronal region of the CBBM grafted socket might not be influenced by the presence of a periapical lesion.

Atraumatic extraction, implant placement and immediate provisionalization

Front tooth extraction typically results in significant loss of hard and soft tissue volume, both in the vestibular-lingual and mesiodistal directions. As these changes can compromise the esthetic results of prosthetic rehabilitation, extraction techniques that cause minimal trauma to the remnant tissues are applied in combination with immediate implant placement to minimize such alterations. The case reported in the present article illustrates a therapeutic plan consisting of atraumatic extraction followed by immediate implant placement and provisionalization. When carefully indicated and planned, our results indicate that this technique may provide promising immediate results relative to the maintenance and stability of the peri-implanted tissues.

Labial soft tissue volume evaluation of different techniques for ridge preservation after tooth extraction: a randomized controlled clinical trial

OBJECTIVE

To volumetrically evaluate soft tissue changes of different ridge preservation techniques compared to spontaneous healing 6 months after tooth extraction.

MATERIALS AND METHODS

In each of 40 patients, one single-rooted tooth was extracted and four treatment modalities were randomly assigned to the following groups (n = 10 each): A) ß-tricalcium-phosphate-particles with a polylactid coating (ß-TCP), B) demineralized bovine bone mineral with 10% collagen covered with a collagen matrix (DBBM-C/CM), C) DBBM with 10% collagen covered with an autogenous soft tissue punch graft (DBBM-C/PG), D) spontaneous healing (control). Impressions were obtained before extraction and 6 months later, casts were digitized and volumetric changes at the buccal soft tissues were determined. One-way anova was performed and pair-wise Wilcoxon rank sum test with Bonferroni-Holm method was applied for comparison of differences between two groups.

RESULTS

After 6 months, horizontal contour changes accounted for -1.7 ± 0.7 mm (A), -1.2 ± 0.5 mm (B), -1.2 ± 0.7 mm (C) and -1.8 ± 0.8 mm (D). None of the group comparisons reached statistical significance.

CONCLUSIONS

Six months after tooth extraction all groups revealed a horizontal volume change in the buccal soft tissue contour. Application of DBBM-C/CM or DBBM-C/PG reduced the amount of volume resorption compared to ß-TCP or spontaneous healing without reaching statistically significant difference.

Soft Tissues Changes After Immediate and Delayed Single Implant Placement in Esthetic Area: A Systematic Review

The aim of the present study was to conduct a systematic review of the literature to compare soft tissue aspects of immediate and delayed implant placement in esthetic areas. This review of literature was conducted in the following databases: MEDLINE (PubMed), Lilacs, Scielo, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL). For those studies that met the inclusion/exclusion criteria, the results were analyzed and summarized according to the treatment protocol used for implant placement. The primary parameters taken into consideration were papilla level (PL) and marginal mucosa level (MML) around implants. Four randomized controlled trials (RCT) were selected for analysis, but all were deemed as being of poor quality according to quality assessment. No studies reported any statistically significant differences concerning the soft tissue esthetic parameters analyzed around immediate or delayed implants at any follow-up periods reported. However, PL results seemed to be more reliable than were MML results, due to the PL standardization of the method of analysis, which showed a tendency for poorer results around immediately placed implants. In conclusion, although the results are based on only a few poor quality RCTs, both treatment options for implant placement demonstrated similar outcomes in the esthetic area, especially when PL was considered.

Use of sintered xenograft over allograft for ridge augmentation: technique note

Patients often present with tooth or implant complications with loss of significant bone width and the need for bone volume for implant placement and maintenance of ridge contour for esthetics. The technique described is a low-morbidity, highly predictable method to restore these sites. A case series of 12 patients followed for 2 years is presented.

Ridge preservation after tooth extraction

BACKGROUND

Following tooth extraction, the alveolar ridge will undergo dimensional changes. This change may complicate the subsequent restorative procedure when oral implants are chosen. "Alveolar ridge preservation" has been assessed in various studies.

AIM

To evaluate the more recent studies on this topic and to explore new insights under this topic.

MATERIAL AND METHODS

Animal studies and clinical studies have addressed different techniques.

RESULTS AND CONCLUSIONS

Implants placed into the fresh extraction sockets do not prevent the resorption of the alveolar bone. Simultaneous guided bone regeneration could partially resolve alveolar bone resorption. The use of root-formed implants does not preserve alveolar ridges. Moreover, various bone substitutes have been tested: magnesium-enriched hydroxyapatite, human demineralized bone matrix, and deproteinized bovine bone mineral have been shown to be effective in ridge preservation. Applying the guided bone regeneration principle using bone substitutes together with a collagen membrane has shown clear effects on preserving alveolar ridge height as well as ridge width. Soft tissue grafts or primary closure did not show beneficial effect on preserving the alveolar bone.

Bone substitutes for peri-implant defects of postextraction implants

Placement of implants in fresh sockets is an alternative to try to reduce physiological resorption of alveolar ridge after tooth extraction. This surgery can be used to preserve the bone architecture and also accelerate the restorative procedure. However, the diastasis observed between bone and implant may influence osseointegration. So, autogenous bone graft and/or biomaterials have been used to fill this gap. Considering the importance of bone repair for treatment with implants placed immediately after tooth extraction, this study aimed to present a literature review about biomaterials surrounding immediate dental implants. The search included 56 articles published from 1969 to 2012. The results were based on data analysis and discussion. It was observed that implant fixation immediately after extraction is a reliable alternative to reduce the treatment length of prosthetic restoration. In general, the biomaterial should be used to increase bone/implant contact and enhance osseointegration.

Residual ridge dimensions at edentulous maxillary first molar sites and periodontal bone loss among two ethnic cohorts seeking tooth replacement

OBJECTIVES

To study residual ridge dimensions at edentulous first molar sites in relation to periodontal bone loss among cohorts of partially edentulous Asian Indian and Hong Kong Chinese subjects seeking tooth replacement.

MATERIALS AND METHODS

A total of 628 edentulous maxillary first molar sites were analyzed on Cone Beam Computed Tomography scans of 225 Asian Indian (I) and 232 Hong Kong Chinese (C) partially edentulous adults seeking tooth replacement. Age, ethnicity, gender, total tooth loss, the presence or absence of adjacent teeth, categories of periodontal status defined according to radiographic alveolar bone loss (P0: periodontal health, P1: incipient to moderate disease, P2: severe periodontal disease) and sinus membrane abnormalities were noted. Alveolar ridge height (RH), widths at 1 and 3 mm from crest (RW1; RW3), and relative position of the bone crest (RR) were measured.

RESULTS

Prevalence of P2 status was most frequent in both cohorts(C: 50.4% I: 49.2%). P2 had lowest ridge heights; 13.1% C P2 and 14%I P2 had RH < 2 mm. Sites with both RH <8 mm and RW1 < 6 mm occurred at 59%C P2 and 68%I P2. Sinus membrane abnormalities were most frequent in P2. Periodontal status and sinus membrane abnormality increased the odds of RH <5 mm and RH <8 mm more than 2-fold; additionally, gender and ethnicity significantly impacted RH <8 mm. Gender and adjacent tooth status significantly affected RW1.

CONCLUSION

Incident advanced periodontal disease was common among Asian Indian and Hong Kong Chinese subjects seeking tooth replacement and associated with lower available bone heights. Ethnicity, gender, sinus membrane thickening affected available bone height in the subsinus region, while the presence of adjacent teeth- and age-affected residual ridge width.

A simplified technique for recording an implant-supported ovate pontic site in the esthetic zone

Implant-supported fixed dental prostheses present an esthetic challenge, especially when an ovate pontic site has been progressively developed during the guided soft-tissue healing process with an interim restoration. This article describes a technique for an accurate capturing of the molded ovate pontic site of an implant-supported fixed dental prostheses and for transferring it to the definitive cast, which facilitates the dental ceramist's ability to design and fabricate an ovate pontic with adequate intaglio contours.

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.

A randomized controlled clinical trial to evaluate a new xenograft for alveolar socket preservation

OBJECTIVE

The aim of this clinical trial was to compare the effect of Bio-Oss(®) and a new bovine xenograft (Osseus(®) ) in alveolar sockets after a 24-week healing period.

MATERIALS AND METHODS

A total of 20 adult volunteers ages 30-60 were subjected to single tooth extraction. A tooth extraction was performed at the baseline. All sites were randomly allocated to two test groups (TG1: grafted using a new bovine xenograft, Osseus(®) , and TG2: grafted using commercially available bovine xenograft-Bio-Oss(®) ). Six months later, a sample of the grafted area was obtained and implants were inserted in the same site. Histological sections were examined focusing on the presence of fibrous connective tissue (CT), and newly formed bone in direct contact with the graft. The HE-stained sections were subjected to histomorphometrical evaluation using Image Pro-Plus(®) software (Release 7.0). The definitive crown was placed 3 months later.

RESULTS

Upon completion of the study, no patients were removed from the study and all inserted implants (10 in each group) were eventually integrated. After 6 months, in the TG1, the mean value of new bone formation was 33.7 (± 7.1), for CT was 32.3 (± 8.9) and for the remaining biomaterial was 10.7 (± 16.2). In the TG2, the mean value of new bone formation was 19.3 (± 22.6), of the CT was 49.9 (± 14.1) and of the remaining biomaterial was 22.6 (± 7.9).

CONCLUSIONS

No statistically significant difference was observed between TG1 and TG2 after 6 months (P > 0.05), and both biomaterials afforded a more favorable implant position.

Alveolar ridge reduction after tooth extraction in adolescents: an animal study

OBJECTIVE

The mechanism for tooth extraction induced residual alveolar ridge reduction (RRR) during adolescence is poorly understood. This study investigated the alveolar bone morphology, growth, resorption and functional loading at normal and extraction sites using an adolescent pig model.

DESIGN

Sixteen 3-month-old pigs were divided into two groups - immediate post-extraction (IE) and 6-week post-extraction (SE). The IE group received an extraction of one deciduous mandibular molar, immediately followed by a final experiment to record masseter muscle EMGs and strains from the buccal surface of the extraction and contralateral non-extraction sites during function (mastication). The SE group was given the same tooth extraction, then kept for 6 weeks before the same final functional recording as the IE group. Both groups also received baseline (pre-extraction) EMGs and fluorescent vital stains 10 and 3 days before the final functional recording. Immediately after the final functional recording, animals were euthanized and alveolar bone specimens from extraction and contralateral non-extraction sites were collected and used to analyse alveolar bone morphology, apposition and resorption based on fluorescent and hematoxylin and eosin stained histological sections.

RESULTS

At control sites (IE-extraction, IE-non-extraction and SE-non-extraction), the alveolar ridges grew gingivally and buccally. Bone formation characterized the buccal surface and lingual bundle bone, whereas resorption characterized the lingual surface and buccal bundle bone. The SE-extraction sites showed three major alterations: convergence of the buccal and lingual gingival crests, loss of apposition on the lingual bundle bone, and decelerated growth at the entire buccal surface. These alterations likely resulted from redirected crestal growth as part of the socket healing process, loss of tongue pressure to the lingual side of the teeth which normally provides mechanical stimulation for dental arch expansion, and masticatory underloading during the initial post-extraction period, respectively.

CONCLUSIONS

These data indicate that the initial phase of RRR in adolescents is a product of modified growth, not resorption, possibly because of decreased mechanical stimulation at the extraction site.

Evaluation of healing following tooth extraction with ridge preservation using cortical versus cancellous freeze-dried bone allograft

BACKGROUND

The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze-dried bone allograft (FDBA) in non-molar extraction sockets.

METHODS

Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical versus cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17 to 21 weeks (average: 18.2 weeks), and a 2-mm-diameter core biopsy was obtained before implant placement. Histomorphometric analysis was performed to determine percentage of new bone formation, residual graft material, and non-mineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement.

RESULTS

There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (P = 0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group compared with the cancellous FDBA group (P = 0.019). A significantly greater percentage of non-mineralized CT/other material was found in the cancellous FDBA group compared with the cortical FDBA group (P = 0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group.

CONCLUSIONS

This is the first reported study to compare the histologic changes following tooth extraction with ridge preservation in humans using cortical versus cancellous FDBA. There were no differences in the percentage of new bone formation between the groups.

A review on alveolar ridge preservation following tooth extraction

CONTEXT

The question that clinicians face is whether the use of bone replacement grafts and/or barrier membranes enhance their ability to provide for the future placement of a dental implant or to maximize ridge dimensions following the extraction of a tooth versus no additional treatments.

EVIDENCE ACQUISITION

The evidence was obtained by search of Entrez PubMed and manual search of The International Journal of Oral and Maxillofacial Implants, The International Journal of Periodontics & Restorative Dentistry, Clinical Oral Implant Research, The Journal of Periodontology, The Journal of Clinical Periodontology, and The Compendium of Continuing Education in Dentistry. Key search words included Guided Bone Regeneration, Dental Extraction, Tooth Extraction, Bone Replacement Graft, Alveolar Ridge. The years of search included from January 2011 through February 2012.

EVIDENCE SYNTHESIS

The recurring theme was that there was considerable heterogeneity to study designs, time periods, and methods of evaluation. This created great difficulty in trying to answer with good high-quality evidence questions about the techniques and materials to be used for maximizing regeneration at the time of tooth extraction or in which situations this ought to be used.

CONCLUSIONS

There appears to be consensus from the reviewed literature supporting ridge preservation techniques as a whole. Multiple studies demonstrated less ridge resorption occurring when alveolar ridge preservation procedures were used versus the placement of no graft material in fresh alveolar sockets. The analysis did not show any grafting materials demonstrating a clear benefit over any others or that a barrier membrane is necessary. The evidence is also too premature about whether socket preservation efforts require primary closure. In the emerging area of growth factors, there is no high-quality evidence to either support or refute their use.

BACKGROUND

Tooth extraction is one of the most widely performed procedures in dentistry today and it has been historically well documented that this procedure may induce significant dimensional changes of the alveolar ridge. The dilemma that clinicians face is how to manage tooth extractions to provide for the future placement of a dental implant or to maximize ridge dimensions for the fabrication of a fixed or removable prosthesis. If performed inadequately, the resulting deformity can be a considerable obstacle to the esthetic, phonetic, and functional results that both our patients and we clinicians expect at this current time.