Horizontal Bone Thickness Research Articles

Evaluation of the clinical and radiographic effectiveness of treating peri-implant bone defects with a new biphasic calcium phosphate bone graft: a prospective, multicenter randomized controlled trial.

Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 40% β-TCP and 60% HA compared to demineralized bovine bone mineral (DBBM). This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent t-test and the χ² test. Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, P=0.133), postoperative discomfort, or early wound healing. No adverse or fatal complications occurred in either group. The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM. Clinical Research Information Service Identifier: KCT0006428.

The clinical efficacy of periodontally accelerated osteogenic orthodontics in patients with bone fenestration and dehiscence: a retrospective study

PurposeThe objective of the study was to explore the effect of periodontally accelerated osteogenic orthodontics (PAOO) in orthodontic patients with bone dehiscence and fenestration in the anterior alveolar region of the mandible.MethodsA retrospective study was performed in 42 patients with bone dehiscence and fenestrations in the anterior alveolar region of the mandible who underwent the PAOO technique. The bleeding index (BI), probing depth (PD), keratinized gingiva width (KGW), gingival recession level (GRL), and gingival phenotype were recorded and assessed at baseline and 6 and 12 months postoperatively. Cone-beam computerized tomography was used to measure bone volume in terms of root length (RL), horizontal bone thickness at different levels, and vertical bone height at baseline and 6 months and 12 months after surgery.ResultsThe sample was composed of 42 patients (22 males and 20 females; mean age, aged 25.6 ± 4.8 years) with 81 teeth showing dehiscence/fenestrations and 36 sites presenting gingival recessions. There was no significant difference in BI, PD, or KGW (between baseline and 6 or 12 months postoperatively) based on the clinical evaluations (P > 0.05). Gingival recession sites demonstrated a significant reduction in the GRL after surgery (P < 0.05). Furthermore, the proportion of teeth with a thick gingival phenotype increased from 33.61% at baseline to 53.13% at the end of the follow-up. In addition, the bone thickness measurements at the mid-root and crestal levels were markedly increased compared with the baseline values (P < 0.05), although the increase in thickness at the apical level was not statistically significant (P > 0.05).ConclusionsWithin the limitations of the study, the results show that the PAOO technique is beneficial to periodontal conditions in terms of soft and hard tissue augmentation. The PAOO procedure may represent a safe and efficient treatment for orthodontic patients with bone dehiscence and fenestration.Trial registrationThis study was approved by the ethics committee of the stomatological hospital affiliated with Xi'an Jiaotong University (xjkqll [2019] No. 016) and registered in the Chinese Clinical Trial Registry (ChiCTR2100053092).

Periosteum coverage versus collagen-membrane coverage in periodontally accelerated osteogenic orthodontics: a randomized controlled clinical trial in Class II and Class III malocclusions

BackgroundPeriodontal accelerated osteogenic orthodontics (PAOO) is a widely-used clinical procedure that combines selective alveolar corticotomy, particulate bone grafting, and the application of orthodontic forces. Different modifications of PAOO such as collagen-membrane coverage can better benefit patients from preventing displacement of grafts. Due to its stability, collagen-membrane coverage gradually gained popularity and became a widely-used procedure in traditional PAOO technique.ObjectivesTo quantitatively investigate the radiographic changes of alveolar bone, periodontal soft tissue changes of the mandibular anterior teeth and postoperative complications in periosteum-covered techniques compared with traditional surgical technique in PAOO.MethodsOrthodontic camouflage for dental Class II or decompensation for skeletal Class III malocclusions were included; Patients with bone defects on the buccal aspects of the anterior mandible regions confirmed by clinical and radiographic examination were randomly divided into the periosteum coverage group or traditional technique group for PAOO. Cone-beam computerized tomography (CBCT) scans were obtained before treatment (T0) and 1 week (T1) and 12 months (T2) after operation. The primary outcome variable was the vertical alveolar bone level (VBL), the secondary evaluation parameters included labial horizontal bone thickness at the midpoint of the middle third (MHBT) or apical third (AHBT) to the limit of the labial cortical surface during a 12-month follow-up. Postoperative sequelae were evaluated after 2 days and 7 days in both the groups. Periodontal parameters were analyzed at T0 and T2.ResultsThirty-six adult subjects were eligible and recruited in the present study. Although experimental group exhibited more severe infection, no significant differences of the postoperative symptoms or periodontal parameters was found between the 2 groups (P > 0.05). All patients were examined respectively using CBCT at baseline (T0), postoperative 1 week (T1) and 12 months (T2). Both alveolar bone height and width increased from T0 to T1 (P < 0.001) and then reduced from T1 to T2 (P < 0.001) in both groups. However, significant bone augmentation was achieved in each group from T0 to T2 (P < 0.001). Furthermore, the vertical alveolar bone augmentation in the experimental group increased significantly than that in the traditional surgery (P < 0.05).ConclusionsCompared with traditional PAOO surgery, the periosteum-covered technique provides superior graft stabilization and satisfactory vertical bone augmentation in the labial mandibular anterior area.

Evaluation of alveolar bone changes around mandibular incisors during surgical orthodontic treatment of patients with mandibular prognathism: Surgery-first approach vs conventional orthognathic surgery

This retrospective study aimed to investigate the alveolar bone changes around mandibular incisors in patients with skeletal Class III malocclusion treated with surgery-first orthognathic approach (SFA) and conventional orthognathic surgery (COS) using cone-beam computed tomography scans. Sixty-four patients were divided into 2 groups according to the inclusion of presurgical orthodontic treatment; the SFA group included 32 patients treated without presurgical orthodontic treatment, and the COS group included 32 patients treated with presurgical orthodontic treatment. Cone-beam computed tomography scans were obtained before treatment, after presurgical orthodontic treatment, and after treatment for the COS group and were obtained before and after treatment for the SFA group. The measurements of vertical alveolar bone height and horizontal bone thickness at 4 levels and the alveolar bone area surrounding the mandibular incisors were compared according to the treatment progress and groups. The vertical bone levels and horizontal bone thickness of the labial and lingual sides and the area of the alveolar bone around the mandibular incisors were reduced after treatment in both SFA and COS groups. Vertical bone loss was more prominent than horizontal bone loss after treatment in both groups, and alveolar bone loss was greater on the lingual side than on the labial side. There were no significant differences in alveolar bone changes around the mandibular incisor between the SFA and COS groups. However, the alveolar bone was reduced more in the COS group than in the SFA group. The results indicate that SFA and COS may trigger degeneration of the alveolar bone around the mandibular incisors after treatment in patients with mandibular prognathism. Careful consideration is needed to avoid iatrogenic degeneration of the periodontal support around the incisors, particularly during presurgical orthodontic treatment.

Bone Dimensional Change Following Immediate Implant Placement in Posterior Teeth with CBCT: A 6-Month Prospective Clinical Study.

This prospective clinical study aimed to evaluate the peri-implant hard tissue dimensional change at 6 months of immediate implant placement with bone graft materials in the posterior area using cone-beam computed tomography (CBCT). Twelve dental implants were placed concurrently following tooth extraction in the posterior area and filled with xenograft particles. The CBCT images were taken immediately after surgical procedures and then at 6 months follow-up. To evaluate the hard tissue changes, the vertical and horizontal bone thickness were analyzed and measured using ImageJ software. Paired t-test or Wilcoxon match-pair signed-rank test was done to analyze the changes of hard tissue values at the same level between immediately and 6 months following immediate implant placement. Independent t-test or Mann–Whitney U test was used to analyze the dimensional change in the vertical and horizontal direction in buccal and lingual aspects. The level of significance was set at p value = 0.05. All implants were successfully osseointegrated. At 6 months follow-up, the vertical bone change at the buccal aspect was −0.69 mm and at the lingual aspect −0.39 mm. For horizontal bone thickness, the bone dimensional changes at 0, 1, 5, and 9 mm levels from the implant platform were −0.62 mm, −0.70 mm, −0.24 mm, and −0.22 mm, respectively. A significant bone reduction was observed in all measurement levels during the 6 months after implant placement (p value < 0.05). It was noted that even with bone grafting, a decrease in bone thickness was seen following the immediate implant placement. Therefore, this technique can be an alternative method to place the implant in the posterior area.

Dimensional changes of buccal bone in the edentulous maxilla with telescopic-retained implant-supported fixed dental prostheses

Statement of problemThe buccal bone in an edentulous maxilla loses thickness over time because of physiological changes. However, the dimensional changes of the buccal bone in an edentulous maxilla with an implant-supported fixed dental prosthesis are unknown. PurposeThe purpose of this retrospective clinical study was to evaluate cone beam computed tomography (CBCT) images of the dimensional changes of the buccal bone in edentulous maxillae with complete arch telescopic-retained implant-supported fixed dental prostheses (CTI-FDPs) after 6 years by using a professional retrieval system. Material and methodsThis study included 17 participants with edentulous maxillae who had been provided with CTI-FDP with 121 taper joint implants. A three-dimensional radiographic analysis by using CBCT was performed at implant insertion (0 years) and after 6 years. Vertical and horizontal bone measurement values were evaluated. During horizontal bone thickness measurement, 4 different levels, 0, 2, 4, and 6 mm apical to the implant shoulder, were evaluated as bone value (BV)0mm, BV2mm, BV4mm, and BV6mm, respectively. The BVs were compared with the Wilcoxon signed-rank test and Kruskal-Wallis test (α=.05). In addition, the Spearman rank correlation coefficient was used to identify 0yBV factors that influence the 6yBVs. A nonlinear regression analysis was used to clarify the slopes of 0yBVs and 6yBV0mm. ResultsSignificant decreases in vertical and horizontal BVs were found between 0 years and 6 years (P<.05). However, no significant difference was observed in bone loss at 6 years at any of the vertical and horizontal measurement points (P≥.05). When 0yBVs related to 6yBV0mm were analyzed, 0yBV0mm and 0yBV2mm showed strong correlations with 6yBV0mm (|r|≥.7). In the regression analysis, a 0yBV0mm of 0.58 mm and 0yBV2mm of 0.78 mm could be critical factors associated with a 6yBV0mm of 0 mm. A 6yBV0mm of 0yBV0mm more than 0.58 mm was significantly higher than a 6yBV0mm of 0yBV0mm less than 0.58 mm (P<.001). Moreover, a 6yBV0mm of 0yBV2mm more than 0.78 mm was significantly higher than a 6yBV0mm of 0yBV2mm less than 0.78 mm (P<.001). ConclusionsThe buccal bone in an edentulous maxilla with fixed implant-supported prostheses lost significant vertical and horizontal bone thicknesses after 6 years. At implant insertion, both a 0.58-mm buccal bone on the platform and a 0.78-mm buccal bone at 2 mm apical to the implant shoulder are necessary for longer term maintenance of bone on the platform of implants specifically supporting CTI-FDPs.

Implants sites with concomitant bone regeneration using a resorbable or non-resorbable membrane result in stable marginal bone levels and similar profilometric outcomes over 5years.

To assess clinical and radiographic outcomes as well as the profilometric contour alterations of peri-implant hard and soft tissues around single implants treated with simultaneous guided bone regeneration (GBR) at 5years. Twenty-seven patients presenting with a single tooth gap in the esthetic zone received a two-piece implant. GBR was randomly performed using a resorbable (RES) or a non-resorbable membrane (N-RES) combined with a bone substitute material. Follow-up examinations were performed at baseline (BL=crown insertion), 1year (FU-1), 3years (FU-3), and at 5years (FU-5) including clinical and radiographic parameters as well as profilometric changes. Statistics were performed by means of parametric and nonparametric tests. At 5years, 20 out of 27 patients (9 RES, 11N-RES) were re-examined. Median values for probing depth changed insignificantly between BL and FU-5 in both groups. The median marginal bone levels were located 0.23mm (0.06; 0.46; RES) and 0.17mm (0.13;0.28; N-RES) below the implant shoulder at FU-5 (changes over time p<.05). The calculated median profilometric change between BL and FU-5 was -0.28mm (-0.53;-0.20; RES; p=.016) and -0.24mm (-0.43;0.08; N-RES; p=.102; intergroup p=.380). The horizontal bone thickness decreased significantly between re-entry and FU-5 for group RES at all measured levels (p<.05) measuring 0.87mm (0.0; 2.05) at the implant shoulder, whereas the decrease for group N-RES was insignificant (p=.031) with 0mm (0; 0.84) at the implant shoulder at 5years. Implants sites with concomitant GBR using a resorbable or non-resorbable membrane revealed stable marginal bone levels and clinical outcomes. Profilometric changes were clinically negligible over 5years. The observed change in hard tissue thickness was partially compensated by an increase in soft tissue thickness.

Assessment of soft and hard tissue dimensions following different treatment approaches of ligature‐induced peri‐implantitis defects

To evaluate peri-implant tissue dimensions following nonsurgical (NS) and surgical therapy (S) employing different decontamination protocols of advanced ligature-induced peri-implantitis in dogs. Peri-implantitis defects (n=5 dogs, n=30 implants) were randomly and equally allocated in a split-mouth design to NS or S treatment using either an Er:YAG laser (ERL), an ultrasonic device (VUS), or plastic curettes+local application of metronidazole gel (PCM), respectively. Horizontal bone thickness (hBT) and soft tissue thickness (hMT) were measured at different reference points: (v0) at the marginal portion of the peri-implant mucosa (PM); (v1) at 50% of the distance from PM to bone crest (BC); (v2) at the BC; (v3) at the most coronal extension of the bone-to-implant contact. Vertical peri-implant tissue height was calculated from PM to BC. All of the treatment groups showed a gradual hMT increase from v0 to the v2 reference point, followed by a reduction from v2 to the v3 region. The S-VUS subgroup tended to be associated with higher hMT values at the v0 region than the NS-VUS subgroup (0.44mm versus 0.31mm). PM-BC distance varied from 2.22 to 2.83mm in the NS group, and from 2.07 to 2.38 in the S group. Vertical and horizontal peri-implant tissue dimensions were similar in different treatment groups.

Three-dimensional observations of the incisive foramen on cone-beam computed tomography image analysis.

PurposeThe purpose of this study was to utilize cone-beam computed tomography (CBCT) image analysis to obtain anatomical information related to the morphology of the incisive foramen to provide useful data regarding implant placement and clinical procedures such as anesthesia.MethodsThe study included 167 patients who underwent CBCT scans over 20 years. Three components were measured: 1) the anteroposterior and mediolateral diameter of the incisive foramen, 2) the horizontal bone thickness anterior to the incisive foramen, and 3) the vertical bone height coronal to the incisive foramen. All measurements were expressed as mean±standard deviation and were analyzed by a single examiner.ResultsThe anteroposterior diameter of the incisive foramen was wider than the mediolateral diameter (P<0.001). The diameter of the incisive foramen in patients in whom the central incisors were present was smaller than that in those in whom at least one central incisor was absent, but no statistically significant difference between the groups was observed. The horizontal bone thickness in the patients with central incisors was statistically significantly larger than that in the patients without at least one central incisor (P<0.001). The same pattern was observed with regard to vertical height, but that difference was not statistically significant.ConclusionsThe buccal bone thickness anterior to the incisive foramen was significantly decreased after central incisor loss. It is necessary to identify the morphology of the bone and the location of the incisive foramen via CBCT to avoid invasion of the incisive foramen and nasopalatine canal.

Initial Bone Volume Changes After Immediate Implant Placement Associated with Filling the Gap Using Bovine Bone in Molar Sites.

The aim of this cone beam computed tomography (CBCT) study was to assess bone volume changes in molar sites after modified immediate implant placement with xenografts. This prospective study was performed between June 2015 and September 2016. Surgical procedures included modified implant site preparation, atraumatic tooth extraction, implant placement, and bone grafting with deproteinized bovine bone mineral. CBCT scans were taken at the day of surgery and 6 months after surgery. Horizontal and vertical bone dimensional changes were evaluated through these two CBCTs, including variations of horizontal bone thickness (HBT), vertical bone height (VBH), and the distance from the implant platform to the tip of the intradental bone peak (DIP). Fifteen patients with 17 hopeless molars were included, and no implant was lost during the observation period. With measurements at five different parallel levels (0, 1, 2, 4, and 6 mm apical to the implant platform), the mean HBT in millimeters and percentage between these two time points ranged from -0.88 (33%) to -0.03 (0.7%) buccally and -0.45 (12%) to -0.02 (0.4%) lingually. The change of VBH was greater buccally (0.74 ± 0.32 mm, P < .01) than lingually (0.40 ± 0.17 mm). DIP was reduced 0.46 ± 0.27 mm mesially and 0.39 ± 0.21 mm distally. In molar sites, flapless modified immediate implant placement with deproteinized bovine bone is a predictable treatment. However, the dimensional change of the ridge should still be expected, and buccal bone resorption is more evident than lingual.

Influence of different implant operative procedures on morphologic changes in peri-implant alveolar bone and soft tissue: a one-year prospective clinical study

PurposeTo prospectively evaluate morphological changes in the horizontal and vertical dimensions of peri-implant tissue at 1-year post-prosthesis implantation. MethodsThirty-four patients who had received implants with conical connections in the aesthetic region were included in the follow-up study. Patients had received either traditional delayed implant placement or tissue augmentation with or without immediate implant placement. The horizontal and vertical dimensions of the buccal alveolar bone of the implant and its surrounding soft tissues were then evaluated using cone beam computed tomography. ResultsImplants placed alongside tissue augmentation, with or without immediate placement, were as successful as those placed into sites with traditional delayed implant placement. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone height (r=0.585, p<0.05) and vertical soft tissue height (r=0.378, p<0.05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (r=0.627, p<0.05). ConclusionsRegardless of the bone and soft tissue augmentation approach, implants with conical connections may effectively preserve peri-implant tissues. However, the thickness of the peri-implant soft tissue is essential, because a change in soft tissue margin level tends to be affected by the thickness of the peri-implant soft tissue rather than the bone width.

Randomized clinical study assessing two membranes for guided bone regeneration of peri‐implant bone defects: clinical and histological outcomes at 6 months

To test whether or not one of two membranes is superior for peri-implant-guided bone regeneration in terms of clinical and histologic outcomes. In 27 patients, 27 two-piece dental implants were placed in single-tooth gaps in the esthetic area. Buccal dehiscence and/or fenestration-type defects were regenerated using demineralized bovine bone mineral and randomly covered with either a resorbable membrane (RES) or a titanium-reinforced non-resorbable membrane (N-RES). Clinical measurements included vertical defect resolution and the horizontal thickness of regenerated bone at implant placement and at 6months. Statistics were performed by means of nonparametric testing. The remaining mean vertical defect measured 4mm (±2.07) (RES) and 2.36mm (±2.09) (N-RES) (P=0.044) at baseline and 0.77mm (±0.85) (RES) and 0.21mm (±0.80) (N-RES) (P=0.021) at re-entry. This translated into a defect resolution of 85% (RES) and 90.7% (N-RES) (P=0.10). The horizontal thickness after augmentation measured 3.46mm (±0.52) (RES) and 2.82mm (±0.50) (N-RES) (P=0.004). The mean loss in horizontal thickness from baseline to re-entry measured 2.23mm (SD ±1.21) (RES) and 0.14mm (±0.79) (N-RES) (P=0.017). The horizontal changes in thickness at the implant shoulder level were statistically significant between the groups (P=0.0001). Both treatment modalities were clinically effective in regenerating bone as demonstrated by a similar horizontal thickness and vertical defect fill at 6months. The N-RES group exhibited significantly less horizontal bone thickness reduction from baseline to follow-up.

A Novel Surgical Technique for Augmented Corticotomy-Assisted Orthodontics: Bone Grafting With Periosteum

To introduce grafting fixed with the periosteum (dumpling technique) as an alternative surgical technique for augmented corticotomy-assisted orthodontics in the lower anterior region and evaluate the preliminary outcomes. Eleven patients (9 women, 2 men; mean age, 21.4yr) with a thin alveolus or alveolar defect in the lower anterior region by clinical and radiographic examination underwent an augmented corticotomy using the new dumpling technique. Cone-beam computerized tomography was used to evaluate morphologic changes of the lower anterior ridge before treatment (T0) and 1week (T1) and 6months (T2) after the bone-augmentation procedure. Repeated-measures analysis of variance with Bonferroni multiple-comparison test was used to compare variables at each time point. No severe postsurgical complications occurred in any patient. The mean alveolar bone thickness of the labial plate increased from T0 to T1 (P < .001) and decreased from T1 to T2 (P < .001). However, compared with T0, there was still a significant increase in horizontal bone thickness at T2 (P < .05). The vertical alveolar bone level increased from T0 to T1 (P < .001) and was maintained from T1 to T2 (P > .05). No significant differences were found in root length of the lower anterior teeth at these 3 time points (P>.05). In this preliminary study, the dumpling technique for augmented corticotomy-assisted surgical orthodontics showed alveolar bone augmentation by increasing the vertical alveolar height and the horizontal bone thickness in the labial aspect of the anterior mandibular area. However, long-term follow-up is necessary.

Cone-Beam Computed Tomography Evaluation of Horizontal and Vertical Dimensional Changes in Buccal Peri-Implant Alveolar Bone and Soft Tissue: A 1-Year Prospective Clinical Study.

This study evaluated changes in the horizontal and vertical dimensions of the buccal alveolar bone and soft tissue over a 1-year period following implant prosthesis. Thirty-three participants with no history of guided bone regeneration or soft tissue augmentation underwent dental implant placement with different types of connections. The dimensions of the buccal alveolar bone and soft tissue were evaluated immediately and at 1 year after prosthesis from reconstructions of cross-sectional cone-beam computed tomography images. The vertical and horizontal loss of buccal bone and soft tissue around implants with conical connections were lower than around those with external or internal connections. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone and soft tissue height (p < .05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (p < .05). Implants with a conical connection preserve peri-implant alveolar bone and soft tissue more effectively than other connection types. Furthermore, the initial buccal alveolar bone and soft tissue thickness around the implant platform may influence their vertical dimensional changes at 1 year after implant prosthesis.

Cone beam computed tomography evaluation of regenerated buccal bone 5 years after simultaneous implant placement and guided bone regeneration procedures – a randomized, controlled clinical trial

The aim of this controlled clinical study was to compare a polyethylene glycol membrane (PEG) used for bone regeneration of peri-implant defects to a collagen membrane with respect to implant survival rate, dimensions of buccal peri-implant bone and mucosa. Thirty-seven patients who received single tooth implants with simultaneous guided bone regeneration (GBR) in the posterior maxilla or mandible were enrolled in the study. Intra-operative heights of bone defects were assessed prior to bone augmentation. The defects were augmented with xenogenic bone mineral and randomly covered either with a porcine collagen membrane (control) or with a PEG membrane (test). Five years after implant placement, clinical evaluation and cone beam computed tomography (CBCT) scans were performed. Remaining height of bone defect, horizontal bone thickness, level of mucosal margin, and mucosal thickness were assessed in CBCT images. The difference of height of bone defect at implant placement and at 5-year follow-up was calculated. The differences between the two groups were analyzed using two-sided t-test and Mann-Whitney U-test. After 5 years, 32 patients could be included and exhibited an implant survival rate of 100% for both groups. The buccal vertical bone gain between implant placement and 5-year follow-up amounted at 4.3 ± 1.5 (SD) mm and 4.8 ± 2.6 (SD) mm for the control and the test group, respectively (P = 0.493). Neither the bone height nor the thickness reached statistical significant differences between the two groups. The distance between mucosal margin and implant shoulder resulted in 0.8 ± 0.7 (SD) mm in the control and 0.5 ± 0.8 (SD) mm in the test group (P = 0.198). The mucosal thickness reached 1.4 ± 0.5 (SD) mm in the control and 1.3 ± 0.3 (SD) mm in the test group (P = 0.715). There were no significant correlations between height of bone defect at baseline and at follow-up examination and between different 5-year parameters. A polyethylene glycol membrane used for bone regeneration of peri-implant defects performed as successfully as a collagen membrane with respect to implant survival rate and dimensions of the buccal peri-implant bone and mucosa after 5 years.

Augmented Corticotomy Combined With Accelerated Orthodontic Forces in Class III Orthognathic Patients: Morphologic Aspects of the Mandibular Anterior Ridge With Cone-Beam Computed Tomography

This study used cone-beam computed tomography to evaluate morphologic changes of the mandibular anterior ridge after using augmented corticotomy plus accelerated orthodontia to decompensate mandibular incisors in patients with surgical skeletal Class III. Fourteen patients (8 men, 6 women; mean age, 26.14 yr) with skeletal Class III were treated before orthognathic surgery with a technique that combined corticotomy, bone grafting, and accelerated orthodontic forces to decompensate the lower incisors. Three-dimensional cone-beam computed tomograms were taken before treatment (T0) and at the completion of presurgical orthodontic treatment (T1). Measurements of the amount of vertical alveolar bone changes and horizontal bone thickness at the midroot and root apex levels of the mandibular incisors were evaluated. All patients showed significant proclination of the mandibular incisors at T1. The mean alveolar bone thickness from T0 to T1 increased buccally at the midroot and apex levels, showing statistically significant horizontal bone augmentation at the labial side of the lower anterior mandibular teeth (P < .05). The mean amount of vertical bone change did not show any significant vertical loss of alveolar bone. This new combined technique provided adequate decompensation of the mandibular incisors by increasing horizontal bone thickness in the labial aspect of the mandibular anterior area, without any vertical bone loss. This approach decreases the risk of the typical periodontal complications associated with traditional orthodontics, such as marginal bone loss and gingival recession.

A randomized controlled clinical multicenter trial comparing the clinical and histological performance of a new, modified polylactide‐co‐glycolide acid membrane to an expanded polytetrafluorethylene membrane in guided bone regeneration procedures

To compare the clinical and histological outcomes of a resorbable modified polylactide/polyglycolide acid (PLGA) test membrane and a titanium-reinforced expanded polytetrafluorethylene (ePTFE) control membrane used for guided bone regeneration (GBR) around dental implants. A total of 40 patients with peri-implant dehiscence-type defects were randomly allocated to a GBR procedure using either a modified PLGA test or an ePTFE control membrane. Soft tissue condition, implant integration, adverse events and quality of life were recorded during the 6-month healing period. At re-entry peri-implant bone defect dimensions were measured and compared with values recorded at implant/GBR surgery. A biopsy was retrieved for qualitative and quantitative histological analyses. A comparison between the groups was conducted using non-parametric statistical tests. Soft tissue complications were observed in five test patients and two control patients. Except for soft tissue complications and incomplete regeneration, no procedure- or device-related adverse events were observed. The vertical bone defect component was, in mean, reduced by-5.1 mm (95% CI -6.8, -3.3) in the test group and -6.9 mm (95% CI -8.2, -5.5 mm) in the control group. The mean residual vertical defect height measured 1.2 ± 2.4 mm in the test group and 0.3 ± 1.1 mm in the control group meaning a mean defect resolution of 81% in the test group and 96% in the control group (P = 0.161). The horizontal bone thickness at implant shoulder level decreased from a mean of 3.2 mm to 1.4 mm (-56%, mean -1.7 mm, 95% CI -2.3, -1.1) in the test group and from 3.3 mm to 2.5 mm (-24%, mean -0.8 mm, 95% CI -1.3, -0.3) in the control group (P = 0.022). Qualitative and quantitative histological analyses did not show significant differences in the tissue composition between groups. Peri-implant GBR was successfully performed using either of the membranes. The control membrane was able to better maintain the horizontal thickness of regenerated bone and revealed less soft tissue complications. No statistically valid evidence about the superiority of one membrane was found in any other parameters. Soft tissue dehiscences occur with both types of membranes and can impair the amount of regenerated bone.

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients

To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.