Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine‐derived xenograft: a randomized,controlled clinical trial

Objectives: The aim of this randomized, controlled clinical trial was to compare the potential of a synthetic bone substitute or a bovine‐derived xenograft combined with a collagen membrane to preserve the alveolar ridge dimensions following tooth extraction. Methods: Twenty‐seven patients were randomized into two treatment groups following single tooth extraction in the incisor, canine and premolar area. In the test group, the alveolar socket was grafted with Straumann Bone Ceramic^® (SBC), while in the control group, Bio‐Oss^® deproteinized bovine bone mineral (DBBM) was applied. In both groups, a collagen barrier was used to cover the grafting material. Complete soft tissue coverage of the barriers was not achieved. After 8 months, during re‐entry procedures and before implant placement, the horizontal and vertical dimensions of the residual ridge were re‐evaluated and trephine biopsies were performed for histological analysis in all patients. Results: Twenty‐six patients completed the study. The bucco‐lingual dimension of the alveolar ridge decreased by 1.1±1 mm in the SBC group and by 2.1±1 in the DBBM group (P<0.05). Both materials preserved the mesio‐distal bone height of the ridge. No differences in the width of buccal and palatal bone plate were observed between the two groups. The histological analysis showed new bone formation in the apical part of the biopsies, which, in some instances, was in direct contact with both SBC and DBBM particles. The coronal part of the biopsies was occupied by a dense fibrous connective tissue surrounding the SBC and DBBM particles. Conclusion: Both biomaterials partially preserved the width and the interproximal bone height of the alveolar ridge. To cite this article:
Mardas N, Chadha V, Donos N. Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine‐derived xenograft: a randomized, controlled clinical trial.
Clin. Oral Impl. Res. 21 , 2010; 688–698.     

Accelerated Bone Formation in Distracted Alveolar Bone After Injection of Recombinant Human Bone Morphogenetic Protein‐2

Background: This study evaluates the effect of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) on the quality and quantity of regenerated bone when injected into distracted alveolar bone. Methods: Sixteen adult beagle dogs were assigned to either the control or rhBMP‐2 group. After distraction was completed, an rhBMP‐2 dose of 330 μg in 0.33 mL was injected slowly into the distracted alveolar crest of the mesial, middle, and distal parts of the alveolar bone in the experimental group. Histologic and microcomputed tomography analyses of regenerated bone were done after 2 and 6 weeks of consolidation. Results: After 6 weeks of consolidation, the vertical defect height in the middle of the regenerated bone was significantly lower in the rhBMP‐2 group (2.2 mm) than in the control group (3.4 mm) (P <0.05). Additionally, the width of the regenerated bone was significantly greater in the rhBMP‐2 group (4.3 mm) than in the control group (2.8 mm) (P <0.05). The bone density and volume of regenerated bone in the rhBMP‐2 group were greater than in the control group after 6 weeks of consolidation (P <0.001). Conclusion: Injection of rhBMP‐2 into regenerated bone after a distraction osteogenesis procedure significantly increased bone volume in the dentoalveolar distraction site and improved both the width and height of the alveolar ridge and increased the bone density.     

Effect of Simvastatin Prodrug on Experimental Periodontitis

Background: Local application of statins has shown potential in preventing and regenerating bone loss associated with experimental periodontitis. This study evaluates the effect of a novel simvastatin (SIM) prodrug (capable of delivering high doses to periodontitis inflammatory lesion and cells) on experimental periodontitis bone loss and inflammation. Methods: Forty mature female Sprague Dawley rats were subjected to ligature‐induced experimental periodontitis between maxillary first and second molars (M1‐M2). Equal groups were treated with three weekly doses of: 1) prodrug carrier alone (mPEG); 2) 0.5 mg SIM dose equivalent in carrier (SIM/SIM‐mPEG); 3) 1.0 mg SIM/SIM‐mPEG; 4) 1.5 mg SIM/SIM‐mPEG; or 5) ligature alone. Contralateral molars served as unmanipulated controls. Four weeks after initiation of periodontitis, animals were euthanized, the M1‐M2 interproximal was evaluated with microcomputed tomography and histology, and data were analyzed with one‐way analysis of variance. Results: Ligature alone caused a mean bone loss of 1.01 ± 0.06 mm from the cemento‐enamel junction, whereas all doses of SIM/SIM‐mPEG reduced bone loss, especially 1.5 mg SIM/SIM‐mPEG (0.68 ± 0.05 mm, P <0.001), which was not statistically different from contralateral control (0.47 ± 0.06 mm). A dose of 1.5 mg SIM/SIM‐mPEG also reduced percentage of neutrophils compared with carrier alone (2.0% ± 1.0% versus 5.7% ± 1.1%; P <0.05), and increased amount of uninflamed connective tissue in the M1‐M2 interproximal area (65.2% ± 3.3% versus 46.3% ± 3.3%; P <0.001). The mPEG carrier alone did not have bone‐sparing or anti‐inflammatory properties. Conclusion: Multiple local 1.5‐mg doses of a macromolecular SIM prodrug decreases amount of experimental periodontitis bone loss and inflammation in rats.     

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

1 Background

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

2 Methods

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

3 Results

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

4 Conclusions

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

Evaluation of Healing at Molar Extraction Sites With and Without Ridge Preservation: A Randomized Controlled Clinical Trial

Background: To date, limited evidence is available specifically evaluating ridge preservation (RP) and implant placement in molar sites. The primary aim of this study is to radiographically compare alveolar ridge changes with and without RP with cone‐beam computed tomography (CBCT). Methods: This parallel, two‐arm randomized clinical trial included 40 patients evenly distributed between two treatment groups. After molar extraction, sites were allowed to heal naturally or received RP with freeze‐dried bone allograft covered by a non‐resorbable dense polytetrafluoroethylene membrane. CBCT scans were taken immediately and 3 months postextraction, and then a dental implant was placed. Width and height measurements were made radiographically. Results: Significantly greater loss in alveolar ridge height was found in molar sites allowed to heal without RP on the buccal aspect of the socket (RP: ?1.12 ± 1.60 mm versus no RP: ?2.60 ± 2.06 mm, P = 0.01). No significant difference in ridge width loss was found between groups. Two‐thirds ridge width reduction was experienced on the buccal aspect in sites without RP, but width loss was evenly distributed between buccal and lingual aspects when RP was performed. Bone grafting at time of placement was required in 25% of implants in the group without RP versus 10% of implants in the RP group. Conclusions: In molar extraction sites without RP, significantly more reduction in ridge height occurred, and the majority of ridge width loss was localized to the buccal aspect. When RP was performed, ridge width loss was not significantly decreased, but the loss was evenly distributed between facial and lingual aspects of the extraction site.     

Buccal Bone Formation After Flapless Extraction: A Randomized,Controlled Clinical Trial Comparing Recombinant Human Bone Morphogenetic Protein 2/Absorbable Collagen Carrier and Collagen Sponge Alone

Background: Flapless extraction of teeth allows for undisturbed preservation of the nearby periosteum and a source of osteoprogenitor cells. Recombinant human bone morphogenetic protein 2 (rhBMP‐2) has been used for different bone augmentation purposes with great osteoinductive capacity. The aim of this study is to compare the bone regenerative ability of rhBMP‐2 on an absorbable collagen sponge (ACS) carrier to a collagen sponge (CS) alone in extraction sites with ≥50% buccal dehiscence. Methods: Thirty‐nine patients requiring extraction of a hopeless tooth with ≥50% buccal dehiscence were enrolled. After flapless extraction and randomization, either rhBMP‐2/ACS carrier or CS alone was placed in the extraction site. After extraction, a baseline cone beam computed tomography (CBCT) scan was obtained of the site, and a similar scan was obtained 5 months postoperatively. Medical imaging and viewing software were used to compare the baseline and 5‐month postoperative images of the study site and assess ridge width measurements, vertical height changes, and buccal plate regeneration. Results: Radiographically, CBCT analysis showed that with ≥50% of buccal bone destruction, rhBMP‐2/ACS was able to regenerate a portion of the lost buccal plate, maintain theoretical ridge dimensions, and allow for implant placement 5 months after extraction. The test group performed significantly (P <0.05) better in regard to clinical buccal plate regeneration (4.75 versus 1.85 mm), clinical ridge width at 5 months (6.0 versus 4.62 mm), and radiographic ridge width at 3 mm from the alveolar crest (6.17 versus 4.48 mm) after molar exclusion. There was also significantly (P <0.05) less remaining buccal dehiscence, both clinically (6.81 versus 10.0 mm) and radiographically (3.42 versus 5.16 mm), at 5 months in the test group. Significantly (P <0.05) more implants were placed in the test group without the need for additional augmentation. The mean loss in vertical ridge height (lingual/palatal) was less in the test sites but was not significantly (P = 0.514) different between the test and control groups (0.39 versus 0.64 mm). Conclusions: rhBMP‐2/ACS compared to CS alone used in flapless extraction sites with a buccal dehiscence is able to regenerate lost buccal plate, maintain theoretical ridge dimensions, and allow for implant placement 5 months later.     

Evaluation of the Effects of Buccal–Palatal Bone Width on the Incidence and Height of the Interproximal Papilla Between Adjacent Implants in Esthetic Areas

Background: The presence of interproximal papilla depends on the distance between the contact point to the bone crest, as well as the mesio‐distal distance between implants or between implants and teeth. The aim of this study is to evaluate the effects of buccal–palatal bone width on the presence of the interproximal papilla between adjacent implants in esthetic areas of the mouth. Methods: The presence or absence of the gingival papilla, distance from the base of the interproximal contact to the tip of the gingival papilla (black space), distance from the base of the interproximal contact to the alveolar crest (vertical distance), alveolar bone width (bone width) between adjacent implants as well as the spacing between the implants (horizontal distance), and soft‐tissue biotype were assessed in 29 interimplant areas in the upper incisor, canine, and premolar regions of 18 patients. Results: The papilla was always present when vertical distance was ≤5 mm (P ≤0.04) and frequently present when the horizontal distance was ≥4 mm (P = 0.04). The black space was smaller when the vertical distance was ≤5 mm (P ≤0.04) and when the horizontal distance was ≥4 mm (P = 0.76). Bone width and soft‐tissue biotype did not influence the incidence of gingival papilla (P ≥0.41) and black space (P ≥0.15). Conclusion: Within the limits of this study, it can be concluded that bone width and tissue biotype do not have an effect on the incidence and height of papilla between adjacent implants in esthetic areas, and the incidence was greater when vertical distance was ≤5 mm or when horizontal distance was ≥4 mm.     

Effect of Single and Contiguous Teeth Extractions on Alveolar Bone Remodeling: A Study in Dogs

Background: Tooth extraction is associated with dimensional changes in the alveolar ridge. The aim was to examine the effect of single versus contiguous teeth extractions on the alveolar ridge remodeling. Material and Methods: Five female beagle dogs were randomly divided into three groups on the basis of location (anterior or posterior) and number of teeth extracted – exctraction socket classification: group 1 (one dog): single‐tooth extraction; group 2 (two dogs): extraction of two teeth; and group 3 (two dogs): extraction of three teeth in four anterior sites and four posterior sites in both jaws. The dogs were sacrificed after 4 months. Sagittal sectioning of each extraction site was performed and evaluated using microcomputed tomography. Results: Buccolingual or palatal bone loss was observed 4 months after extraction in all three groups. The mean of the alveolar ridge width loss in group 1 (single‐tooth extraction) was significantly less than those in groups 2 and 3 (p < .001) (multiple teeth extraction). Three‐teeth extraction (group 3) had significantly more alveolar bone loss than two‐teeth extraction (group 2) (p < .001). The three‐teeth extraction group in the upper and lower showed more obvious resorption on the palatal/lingual side especially in the lower group posterior locations. Conclusion: Contiguous teeth extraction caused significantly more alveolar ridge bone loss as compared with when a single tooth is extracted.     

Simvastatin application to augment facial jaw bone in a dog model: pilot study

Background: Locally injected simvastatin (SIM) has been shown to induce bone growth in rat models. The purpose of this study is to evaluate the effects of locally injected simvastatin in several human‐like clinical situations in a beagle dog model. Methods: Four beagle dogs completed the study and were used in a split‐mouth design. Dehiscence defects of 5 × 3 mm were created bilaterally on the lateral aspect of the mandibular second premolar (PM2) mesial roots including removal of root cementum. At the same surgery, porous hydroxyapatite–collagen grafts with resorbable membranes with or without 10‐mg SIM were placed buccal to the mandibular first molars (M1). One week later, three weekly local injections of 10‐mg SIM in ethanol and contralateral ethanol alone were initiated at three sites through the buccal mucosa: 1) 6 mm apical to the cemento‐enamel junction (CEJ) of the maxillary fourth premolar (PM4; thin bone over root); 2) 6 mm apical to the CEJ of PM2 (dehiscence defect); and 3) 10 mm distoapical to the CEJ of the maxillary canine (edentulous ridge). Dogs were euthanized 2 months after the final injections. Block sections were harvested and specimens were decalcified and stained with hematoxylin and eosin. Histomorphometry was performed using digitized photographs and analyzed with distribution‐free rank tests. Results: Regarding M1, the distance between CEJ and the alveolar crest was significantly more coronal in the SIM group (P = 0.038). Regarding the edentulous ridge, the width of new bone was significantly greater in SIM injection specimens (P = 0.0164). Regarding PM2, buccal bone in the dehiscence defects lacking periosteum was not augmented in the SIM group. Regarding PM4, the total width of bone 5 mm apical to the coronal height of contour (thin buccal bone covering the root) was significantly wider on the SIM side (SIM, 0.63 ± 0.53 mm; contralateral ethanol alone, 0.25 ± 0.19 mm; P = 0.0098). Conclusion: Locally injected SIM has the ability to induce modest amounts of new bone formation in closed injection sites over a periosteal surface.     

Correction of Buccal Dehiscence During Immediate Implant Placement Using the Flapless Technique: A Tomographic Evaluation

Background: The aim of this study was to evaluate a new technique for treating dehiscence buccal bone sites (Class II) with immediate implant and collagen‐enriched bovine‐derived xenograft blocks without a surgical flap or membrane. Methods: Individuals with at least 5 mm of buccal bone dehiscence were selected for a flapless surgical approach to insert xenograft blocks into buccal dehiscence defects as well as the gap between implant and residual bone wall. No membrane was used. Buccal bone wall height was measured by computed tomography in the preoperative period (T0) and 6 to 12 months after procedure (T1). Likewise, buccal‐lingual width of alveolar ridge as well as thickness of buccal wall was compared with the contralateral tooth. Results: Fourteen patients were selected. Buccal wall height at T1 was not significantly different after 6 to 12 months between the treated and contralateral teeth, although both were greater than T0 (P <0.01). The heights ranged from 6.4 to 16.30 mm at T0, 12.8 to 25.6 mm at T1, and 14.8 to 25.29 mm in the contralateral teeth. Significant differences were observed between treated teeth (T1) and their contralateral, both buccal‐lingually in the alveolar ridge (P = 0.007) and in buccal wall thickness (P = 0.003). Wall thickness ranged from 0.9 mm to 3.81 mm at T1 and 0.25 mm to 1.60 mm in the contralateral teeth. Conclusion: Immediate implant placement at dehiscence buccal bone sites using flapless surgery combined with xenograft blocks provided complete formation of the buccal bone wall up to the implant shoulder.     

Alveolar ridge reconstruction and/or preservation using root form bioglass cones

Abstract. Extraction of a tooth necessitated by factors such as developmental problems, trauma, severe periodontal disease and endodontic problems often causes deformities of the residual alveolar ridge in the maxillary anterior region. These cases are usually difficult to restore prosthetically and they result in poor esthetics and insufficient occlusal function. This study investigated the efficacy of root form bioactive glass cones implanted into (a) artificial sockets produced by bone splitting of previous extraction sites (group BS) and (b) fresh extraction sockets (group FES), We included conventional extraction sockets sutured without implanting the root form bioactive glass cones as a control (group C). A total of 16 patients were treated for whom extractions had been indicated due to severe periodontitis, 6 patients with 7 implant sites having Class II or III alveolar ridge deformities comprised the BS group. 5 patients with 10 implant sites comprised the FES group. Group C, comprised 5 patients with 10 extraction sites. Alveolar ridge width and height measurements were obtained using study casts preoperatively, immediately postoperatively. and at 3 and 12 months after operation. In the BS group, while the width of the alveolar ridge increased by 2.8 ± 1.18mm immediately after ridge augmentation procedure and by 2.4±0.93 mm at 1 year after operation (p<0.01), the height of the alveolar ridge increased by 1.8±1.99 mm and 1.4±1.74 mm respectively (p<0.05). In the FES group, the differences between preoperative original ridge height and width and postoperative measurements were not statistically significant, which demonstrated the efficiency of this method in preserving the alveolar ridge. In group C, while alveolar ridge width after 12 months had not Significantly changed, alveolar ridge height decreased significantly (1.35±1.05 mm. p<0.01). After 12 months, no dehiscences were detected and the differences in height between the groups remained significant. The results of this study indicate that this procedure is efficient in reconstructing alveolar ridges deformed as a result of extraction, particularly relevant in relation to preparation for subsequent restorative treatment.     

The Effect of Removable Partial Dentures on Alveolar Bone Resorption: A Retrospective Study with Cone‐Beam Computed Tomography

Purpose: The aim of this study was to compare vertical and horizontal mandibular alveolar bone resorption by measuring bone morphological variation in Kennedy Class II removable partial denture (RPD) wearers and non‐wearers using cone‐beam computed tomography (CBCT). Materials and Methods: In total, 124 sites in the CBCT scans of 62 (29 RPD non‐wearers, 33 RPD wearers) Kennedy Class II patients were analyzed retrospectively. Three‐dimensional representations of the mandible with superimposed cross‐sectional slices were developed with the CBCT scans to evaluate the mandibular alveolar height and width by measuring distances between the mandibular canal, mylohyoid ridge, alveolar crest, and lower border of the mandible in four regions (eight sites) of Kennedy Class II non‐wearers and wearers of RPDs. Results: Mandibular alveolar bone height and width were significantly lower in edentulous sites when compared with dentate sites in both Kennedy Class II non‐wearers and wearers of RPDs (p < 0.05). Additionally, mean vertical and horizontal mandibular bone resorption was significantly higher in RPD wearers than in non‐wearers (p < 0.05). Conclusions: Vertical and horizontal alveolar bone resorption was found to be higher in the RPD wearing patients when comparing the dentate and edentulous sites.     

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.     

Microcomputed Tomographic Analysis of the Alveolar Ridge Alteration around Extraction Sites with and without Immediate Implants Placement: In Vivo Study

Background: The aim was to assess the alveolar ridge alteration around extraction sites with and without immediate implants according to extraction socket classification (ESC) using microcomputed tomography (micro‐CT). Material and Methods: Ten beagle dogs (mean age and weight: 24 ± 0.83 months and 13.8 ± 0.49 kg, respectively) were randomly divided into three groups according to the ESC. In Group 1 (ESC‐I), bilateral first and third premolars were extracted and replaced with immediate implants. In Group 2 (ESC‐II), two adjacent premolars were extracted with one immediate implant placement in the mesial socket in the maxilla and in the distal socket in the mandible. In Group 3 (ESC‐III), three adjacent teeth were extracted and an immediate implant was placed in the central socket. Primary closure was achieved using resorbable sutures. Buccal sites with dehiscence defects were excluded. After 4 months, subjects were sacrificed and alveolar ridge widths were measured at 1 mm interval in axial and sagittal views, using micro‐CT in sites with and without immediate implants. Results: In sites without immediate implant placement, alveolar ridge width was significantly higher in Group 1(6.1 ± 1.35 mm) than Group 3 (4.14 ± 1.53 mm) (p < .05). In sites with immediate implant placement, the alveolar ridge width was higher among sites in Group 1 (6.4 ± 3.8 mm) than Group 2 (4.8 ± 0.46 mm) (p < .05) and Group 3 (5.02 ± 0.84 mm) (p < .05). Overall, between each corresponding group in both sites with and without immediate implant placement at 1 mm thickness, there was no significant difference in the alveolar ridge widths. Conclusion: With the exception of Group 1 (ESC‐I), immediate implant placement did not prevent or minimize bone remodeling in extraction sites according to ESC.     

Keratinized Gingiva Height Increases After Alveolar Corticotomy and Augmentation Bone Grafting

Background: The aim of the present study is to compare the keratinized gingival tissue (KT) height labial to the mandibular incisors after active orthodontic treatment (AOT) with and without alveolar corticotomy and bone grafting. Methods: Two orthodontically treated groups of 35 patients each, with (Cort) and without (Conv) alveolar decortication and augmentation bone grafting, are matched in this case‐control study for sample size, sex, mandibular premolar extractions, pretreatment age, post‐treatment observation period, and pretreatment KT height. Standardized digital frontal occlusion photographs taken before and at least 1 year after AOT were adjusted to 96 dots per inch and measured with image analysis software for vertical KT height labial to each mandibular incisor. Results: An average of 1.5 years after completion of AOT, KT height had increased significantly by 0.78 mm (P < 0.001) in the Cort group and decreased 0.38 mm (P = 0.002) in the Conv group; a 1.28‐mm KT height gain was demonstrated in the subgroup representing the lowest half of Cort KT height at pretreatment. Mandibular incisor inclination and prominence explained neither the decrease in KT height in Conv nor the KT height gain in Cort. Conclusions: Orthodontic therapy combined with alveolar decortication and augmentation bone grafting resulted in a significant increase in KT height. Although KT height surrounding the dentition has been devalued by evidence‐based studies, the value‐added protection of KT height increase after decortication and augmentation bone grafting offsets the concerns of orthodontic proclination or expanding mandibular incisors facially.     

Measurement of ridge alterations following tooth removal: a radiographic study in humans

Objective: The aim of this study was a radiographic mesiodistal analysis of the shape of the bone crest 3 months after tooth removal. Material and methods: One hundred single tooth extractions were performed on 100 patients because of orthodontic or prosthetic causes. Bite blocks were used for two radiographs: one on the day of extraction and the other after healing of the socket, 3 months later. These X‐rays were used to determine: (1) the most apical distance of alveolar ridge resorption, with baseline as the line between bone‐to‐teeth contact (the greatest distance in bone resorption height) and (2) the mesiodistal distance (MDD) and mesial and distal angles arising after bone tissue modeling. Results: Significant differences (P<0.05) emerged between the MDDs of multiple‐ [8 mm, 95% confidence interval (CI): 6.09, 9.90] and single‐root teeth (5.60 mm, 95% CI: 4.80, 6.50). However, mesial or distal angles or the most apical distance of alveolar ridge resorption did not differ (mean distance in height=4.32 mm, 95% CI: 3.85, 4.78; mean angle=24°). Conclusions: In this study, the post‐extraction mesiodistal bone distance between teeth adjacent to the edentulous ridge depends on the size of the edentulous space. Nevertheless, the distance does not affect the distance in bone loss height. The distance of bone resorption height reaches a balance at the midpoint, which we consider indicative of stable healing. This resorption process must be considered when placing dental implants in fresh extraction sockets, especially in aesthetic sites, because the implant surfaces could be exposed after 3 months. To cite this article:
Moya‐Villaescusa MJ, Sánchez‐Pérez A. Measurement of ridge alterations following tooth removal: a radiographic study in humans.
Clin. Oral Impl. Res. 21 , 2010; 237–242.
doi: 10.1111/j.1600‐0501.2009.01831.x     

Clinical and histomorphometric evaluation of extraction sockets treated with an autologous bone marrow graft

Purpose: The aim of this study was to evaluate the potential of an autologous bone marrow graft in preserving the alveolar ridges following tooth extraction. Materials: Thirteen patients requiring extractions of 30 upper anterior teeth were enrolled in this study. They were randomized into two groups: seven patients with 15 teeth to be extracted in the test group and six patients with 15 teeth to be extracted in the control group. Hematologists collected 5 ml of bone marrow from the iliac crest of the patients in the test group immediately before the extractions. Following tooth extraction and elevation of a buccal full‐thickness flap, titanium screws were positioned throughout the buccal to the lingual plate and were used as reference points for measurement purposes. The sockets were grafted with an autologous bone marrow in the test sites and nothing was grafted in the control sites. After 6 months, the sites were re‐opened and bone loss measurements for thickness and height were taken. Additionally, before implant placement, bone cores were harvested and prepared for histologic and histomorphometric evaluation. Results: The test group showed better results (P<0.05) in preserving alveolar ridges for thickness, with 1.14±0.87 mm (median 1) of bone loss, compared with the control group, which had 2.46±0.4 mm (median 2.5) of bone loss. The height of bone loss on the buccal plate was also greater in the control group than in the test group (P<0.05), 1.17±0.26 mm (median 1) and 0.62+0.51 (median 0.5), respectively. In five locations in the control group, expansion or bone grafting complementary procedures were required to install implants while these procedures were not required for any of the locations in the test group. The histomorphometric analysis showed similar amounts of mineralized bone in both the control and the test groups, 42.87±11.33% (median 43.75%) and 45.47±7.21% (median 45%), respectively. Conclusion: These findings suggest that the autologous bone marrow graft can contribute to alveolar bone repair after tooth extraction. To cite this article:
Pelegrine AA, da Costa CES, Correa MEP, Marques JFC Jr. Clinical and histomorphometric evaluation of extraction sockets treated with an autologous bone marrow graft.
Clin. Oral Impl. Res. 21 , 2010; 535–542.
doi: 10.1111/j.1600‐0501.2009.01891.x     

上颌单颗前牙位点保存后邻面牙槽嵴高度的早期变化

目的 探讨位点保存术对上颌单颗前牙拔除后邻面牙槽嵴高度早期变化的影响,为种植修复龈乳头美学效果提供参考依据。方法 选择需拔除上颌单颗前牙的30例患者为研究对象,将其随机分为试验组和对照组,每组15例。试验组在拔牙同时进行位点保存术（牙槽窝内植入 Bio-Oss骨粉,表面游离龈移植缝合固定）,对照组拔牙后未行其他处理。术后7 d及术后6个月,佩戴个性化数字化放射导板行锥形束CT检查,测量2组近远中邻面牙槽嵴及唇侧中央牙槽嵴高度的变化。结果 试验组近中、远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.358±0.151）mm、（0.322±0.180）mm、（0.826±0.307）mm,对照组近远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.653±0.260）mm、（0.667±0.274）mm、（1.510±0.625） mm。统计分析表明,试验组的牙槽嵴吸收高度小于对照组（P<0.05）,近中、远中邻面牙槽嵴的吸收高度均小于唇侧（P<0.05）。结论 位点保存术可以减少牙拔除后牙槽嵴高度的吸收,提高种植修复龈乳头美学效果。     

上颌单颗前牙位点保存后邻面牙槽嵴高度的早期变化

目的 探讨位点保存术对上颌单颗前牙拔除后邻面牙槽嵴高度早期变化的影响,为种植修复龈乳头美学效果提供参考依据。方法 选择需拔除上颌单颗前牙的30例患者为研究对象,将其随机分为试验组和对照组,每组15例。试验组在拔牙同时进行位点保存术（牙槽窝内植入 Bio-Oss骨粉,表面游离龈移植缝合固定）,对照组拔牙后未行其他处理。术后7 d及术后6个月,佩戴个性化数字化放射导板行锥形束CT检查,测量2组近远中邻面牙槽嵴及唇侧中央牙槽嵴高度的变化。结果 试验组近中、远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.358±0.151）mm、（0.322±0.180）mm、（0.826±0.307）mm,对照组近远中邻面及唇侧中点的牙槽嵴吸收高度分别为（0.653±0.260）mm、（0.667±0.274）mm、（1.510±0.625） mm。统计分析表明,试验组的牙槽嵴吸收高度小于对照组（P<0.05）,近中、远中邻面牙槽嵴的吸收高度均小于唇侧（P<0.05）。结论 位点保存术可以减少牙拔除后牙槽嵴高度的吸收,提高种植修复龈乳头美学效果。     

Effect of Healing Time on New Bone Formation After Tooth Extraction and Ridge Preservation With Demineralized Freeze‐Dried Bone Allograft: A Randomized Controlled Clinical Trial

Background: Clinicians and patients continually search for procedures to decrease time from tooth extraction to restoration. Evidence to date is limited concerning timing of ridge preservation healing and reentry for implant placement. The first objective of this study is to histologically evaluate new bone formation 8 to 10 weeks versus 18 to 20 weeks after extraction of non‐molar teeth and ridge preservation using demineralized freeze‐dried bone allograft (DFDBA). The second objective is to compare dimensional changes including ridge width and height at the two healing time points. Methods: Forty‐four patients had tooth extraction and ridge preservation with DFDBA that was obtained from a single donor. Clinical measurements were made to evaluate ridge height and width. Patients were randomly allocated to short‐term (8 to 10 weeks) and long‐term (18 to 20 weeks) healing groups. Sites were reentered at the appropriate healing time, core biopsy was obtained, and a dental implant was placed. The same ridge dimensions were measured at time of implant placement. Histomorphometric analysis was performed to determine percentage of new vital bone formation, residual graft, and connective tissue (CT)/other. Results: A significantly higher percentage (47.41%) of new vital bone formation was found in the long‐term healing group compared with the short‐term healing group (32.63%) (P = 0.01). There was no significant difference in percentage of residual graft, percentage of CT/other, or ridge dimensional changes. Conclusion: This study indicates significantly greater new vital bone formation occurs after tooth extraction and ridge preservation with DFDBA when sites healed for 18 to 20 weeks compared with 8 to 10 weeks prior to dental implant placement.