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PURPOSE: To evaluate, within a period of 5 years, the bone level in mesial, distal, palatal, and buccal areas around scalloped shape implants immediately placed and loaded with temporary crowns fixed on final prefabricated abutments, and also to evaluate the thickness of buccal bone. MATERIALS AND METHODS: 18 implants were inserted and loaded immediately using computer-assisted design/computer-assisted manufacturing technology on 18 patients to replace single tooth in the esthetic part of the maxilla. The marginal bone level across the scalloped implant neck was measured mesially and distally using intraoral standardized radiographs after crown fixations and 1, 3, and 5 years later. Cone beam computed tomography para-axial cuts images were used to measure bone level buccally and palatally from the implant neck to the implant-to bone contact after 5 years of loading and to evaluate the thickness of the buccal bone at the implant neck and 4 mm apically, immediately after implant placement and 5 years later. RESULTS: All implants were assessed clinically and radiologically after 5 years. No implant failure was recorded, and the average marginal bone variation on mesial and distal sites was 0.114 ± 0.135 mm at crown cementation, 0.239 ± 0.158 mm 1 year later, 0.233 ± 0.182 mm 3 years later, and 0.180 ± 0.182 mm 5 years later. Our findings indicate that at T0, the average thickness of the buccal bone was 2.27 mm at implant neck M0 (ranging from 1.9 to 2.4) and 2.33 mm at 4 mm apically to the implant neck M1 (ranging from 1.9 mm to 2.9 mm). By T4, the mean had decreased to 1.94 mm at M0 (with a range of 1.7 mm to 2.3 mm) and 2.14 mm at M1 (with a range of 1.8 mm to 2.4 mm). After 5 years the mean changes at buccal and palatal bone for all implants were +0.187 ± 0.52 mm and +0.06 ± 0.38 mm respectively. Minor prosthetic problems were observed over the five years: incisal ceramic chipping occurred in two crowns, and two crowns were replaced for esthetic reasons after one year. No loosening of crowns or abutments was reported. CONCLUSIONS: Scalloped neck implants demonstrated a comparable behavior to regular neck implants with similar designs in an immediate implantation and temporization protocol over a five-year period.

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AIM: This case series aimed to evaluate the effectiveness of the autologous circular cortical lamina-anchoring (CCA) technique for horizontal bone augmentation in the maxillary aesthetic region. MATERIALS AND METHODS: A total of 25 patients with 28 implants underwent horizontal bone augmentation using CCA followed by implant placement and crown delivery. The primary outcome measures were alveolar ridge width (ARW) and buccal bone thickness (BBT), whereas the secondary outcome measures included marginal bone loss (MBL), mid-facial mucosal margin loss (MML), clinical assessment of peri-implant and aesthetic parameters, patient-reported outcome measures (PROMs), and implant survival rates. RESULTS: All 25 patients with 28 implants completed the treatment, no dropouts occurred. After CCA, the mean ARW at 1, 2, and 4 mm below the alveolar crest significantly increased from 2.38 ± 0.48, 2.85 ± 0.51, and 3.21 ± 0.53 mm to 6.80 ± 0.48, 6.99 ± 0.50, and 8.08 ± 0.52 mm, respectively. At the 3-year follow-up, the mean BBT0, BBT2, and BBT4 slightly decreased from 2.51 ± 0.26, 2.63 ± 0.31, and 2.75 ± 0.29 mm to 2.43 ± 0.27, 2.51 ± 0.30, and 2.64 ± 0.28 mm, respectively. Although the overall MBL was <0.15 mm, the results were statistically significant. The mean MML at the 3-year follow-up was 0.02 mm. All implant sites showed acceptable peri-implant and aesthetic outcomes. Incisions healed without complications, and no significant differences in PROMs observed at any time point. The 3-year follow-up showed a 100% implant survival rate. CONCLUSION: The autologous CCA technique is a useful method for increasing ARW and maintaining BBT in the maxillary aesthetic region.

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OBJECTIVES: This prospective clinical study aimed to evaluate the accuracy and 1-year clinical follow-up performance of dental implant placement with an autonomous dental implant robot (ADIR) system in full-arch implant surgery. MATERIALS AND METHODS: Twelve patients with edentulous arches or final dentition received 102 implants using the ADIR system. Global platform deviation, global apex deviation, and global angular deviation between the planned and actual implants were calculated after surgery. Data were statistically analyzed for factors including jaws, implant positions, patient sequences, implant systems, and implant length. Surgery duration was recorded. Patients were followed for 3 months and 1 year after surgery. Periodontal parameters, buccal bone thickness (BBT), and facial vertical bone wall peak (IP-FC) were recorded. RESULTS: Among the 102 implants, the mean (SD) global platform deviation, global apex deviation, and global angular deviation were 0.53 (0.19) mm, 0.58 (0.17) mm, and 1.83 (0.82)°, respectively. The deviation differences between the mandible and maxilla did not show statistical significance (p > .05). No statistically significant differences were found for the jaws, implant positions, patient sequences, implant systems, and implant length to the deviations (p > .05). The periodontal parameters, the BBT, and IP-FC remained stable during 1-year follow-up. CONCLUSION: The ADIR system showed excellent positional accuracy. The 1-year follow-up after full-arch implant surgery indicated that the ADIR system could achieve promising clinical performance. Additional clinical evidence is requisite to furnish guidelines for the implementation of the ADIR system in full-arch implant surgery.

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BACKGROUND: This study aimed to compare the efficacy of different gap filling materials in immediate implant in anterior and premolar regions of maxilla. MATERIALS AND METHODS: Thirty-six implants were inserted in patients seeking for replacement of non-restorable maxillary anterior and premolar teeth (esthetic zone) by immediate implant. Patients were randomly distributed into three equal groups, twelve implants in each group. Group 1 received Platelet Rich Fibrin (PRF) into the jumping distance, Group 2 received Xenograft into the jumping distance and Group 3 received Alloplastic bone grafting material into the jumping distance. Implant stability by measuring the changes in Resonance Frequency Analysis (RFA), peri-implant pocket depth, marginal bone loss and changes in buccal bone thickness were evaluated during follow up periods. All the clinical and radiographic data were subjected to statistical analysis by One Way ANOVA test and the Post Hoc Tukey test. RESULTS: This study involved 19 female patients and 17 male patients who received 36 dental implants. There was no significant difference between the study groups regarding implant stability, peri-implant pocket depth and palatal bone loss, while there was a significant difference between PRF Group (Group 1) and the other Groups regarding buccal bone loss and changes in buccal bone thickness. CONCLUSION: PRF can be used as a gap filling material in conjunction with immediate implant placement, but other bone grafting materials give superior result regarding buccal bone loss and changes in buccal bone thickness. TRIAL REGISTRATION: The study was listed on www. CLINICALTRIALS: gov with registration number (NCT05878392) on 26/05/2023. The Institutional Review Board (IRB) of the Faculty of Dentistry, Mansoura University, Mansoura, Egypt, approved the current study in compliance with the seventh revision of the Helsinki Declaration in 2013 (A0103023OS).

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OBJECTIVES: The objective of this study, which included a 5-year follow-up, was to compare peri-implant soft tissue health, crestal bone loss (CBL), and buccal bone thickness (BBT) around triangular cross-section neck (TN) or round neck (RN) implants, using cone-beam computed tomography. MATERIALS AND METHODS: This study was initially designed as a prospective 1-year randomized controlled study and then extended with a 5-year retrospective evaluation of clinical and radiographic records. In the initial 1-year study, a total of 20edentulous patients receiving 40 implants with similar diameters were randomly assigned to the RN or TN groups using a split-mouth design. Pocket probing depths (PPD), plaque index (PI), and gingival index (GI) were recorded at postoperative month 12. CBL and BBT at three levels (0, -2, and -4 mm) were evaluated 1 year after insertion. Five years after insertion, PPD, PI, GI, CBL, and BBT were recorded as patients were recalled for clinical and radiographic monitoring. RESULTS: Nineteen patients completed the study. After 5 years, no significant differences in PPD, PI, and GI scores and BBT values between the two groups (p > .05). The mean ± SD CBL values at the final follow-up visit were -0.71 ± 0.69 mm for TN and -1.03 ± 0.86 mm for RN (p < .01). CONCLUSIONS: These results suggest better crestal bone preservation using implants with TN when compared to RN after a 5-year follow-up. However, TN showed similar results to RN regarding peri-implant soft tissue health and BBT.

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PURPOSE: To evaluate image quality and diagnostic accuracy of buccal bone thickness assessment in maxillary and mandibular anterior region using cone-beam computed tomography (CBCT) and 3-dimensional double-echo steady-state (DESS) MRI for preoperative planning of immediate dental implants in healthy individuals. METHODS: One hundred and twenty teeth in 10 volunteers were retrospectively evaluated for image quality and artifacts using Likert scale (4 = excellent to 0 = decreased). Buccal bone thickness was measured at three measurement points (M1 = 2 mm from the cementoenamel junction, M2 = middle of the root, and M3 = at the root apex) for each tooth in the maxillary (13-23) and the mandibular anterior region (33-43). Descriptive statistics and two-way ANOVA with Tukey's Post-hoc test were performed to evaluate the significant differences (α = 0.05) between both imaging modalities. RESULTS: Image quality showed little to no artifacts and enabled confident diagnostic interpretation (CBCT (3.72 ± 0.46); MRI (3.65 ± 0.49)), with no significant differences between both imaging modalities (p > 0.05). Regarding the assessment of buccal bone thickness at M1-M3 for the teeth 13-23 and 33-43, no significant differences were noted (p > 0.05). MRI demonstrated slight, nonsignificant overestimation of thickness with the canines having mainly a thick buccal bone wall, where thin buccal wall was evident for the central incisors. CONCLUSION: Black bone MRI sequences, such as 3D-DESS MRI, for immediate implant planning provided confidential diagnostic accuracy in bone thickness assessment without significant disadvantages compared to CBCT. Thus, the implementation of no-dose protocols for dental rehabilitation using an immediate loading approach seems promising and could further improve the treatment strategy for dental rehabilitation.

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OBJECTIVES: Dental implants are a known treatment today. It is necessary to have at least 2 mm of bone around the implant, especially in the buccal aspect of the anterior maxilla (esthetic zone). Some systemic conditions, such as menopause, can affect the body's bone mass as well as the alveolar bone. Considering that few studies have been carried out on the effect of menopause on the thickness and topography of alveolar bone, we decided to investigate the effect of menopause on buccal alveolar bone thickness in the anterior maxillary teeth in menopausal women. MATERIAL AND METHODS: In this descriptive-analytical cross-sectional study, two subgroups of menopausal women and nonmenopausal women were considered. Data were extracted from 30 patients referred to a private radiology center in Mashhad for CBCT imaging. In addition, the buccal bone thickness in the crest and middle areas of the anterior maxillary teeth was measured and the difference between the two groups was investigated. The buccal bone thickness of the aesthetic area was evaluated with CBCT Planmeca ProMax 3D Max (Planmeca) by Planmeca Romexis 5.3.4 software, with 200 µm Voxel size and Fov 90 × 60 mm. RESULTS: In this study, 30 women with a mean age of 49.75 ± 3.65 years in the nonmenopausal and menopausal groups were examined. It was found that the mean buccal bone thickness of the anterior maxilla in the nonmenopausal group (0.65 ± 0.25 mm) was higher than in the menopausal group (0.56 ± 0.20 mm), but the difference was not statistically significant (p = .2999). Only in the crestal bone of the right canine, the average bone thickness in nonmenopausal group (0.77 ± 0.33 mm) was significantly higher than the menopausal group (0.49 ± 0.22 mm) (p = .011). CONCLUSIONS: Owing to changes in the volume and thickness of alveolar bone in menopausal women, the thickness of the buccal bone in the aesthetic area decreases, but this is not statistically significant.

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(1) Background: Immediate dental implant placement has been a subject of great interest over the last decade. Here, information regarding the anatomy and bone thickness of the jaw prior to dental implant placement is crucial to increase the surgery's success and the patient's safety. The clinical premises for this approach have been controversially discussed. One of those heavily discussed premises is a buccal bone thickness of at least 1 mm thickness. This meta-analysis aims to systematically review buccal bone thickness (BBT) in healthy patients. Thus, the feasibility of immediate dental implant placement in daily practice can be assessed. (2) Methods: A search in the electronic databases was performed to identify articles reporting on BBT that was measured by computed tomography in adults. (3) Results: We were able to find 45 studies, including 4324 patients with 25,452 analyzed teeth. The analysis showed a BBT at the alveolar crest of 0.76 ± 0.49 mm in the maxillary frontal and of 1.42 ± 0.74 mm in the maxillary posterior region. In the mandible, the average measured values were similar to those in the maxilla (front: 0.95 ± 0.58 mm; posterior: 1.20 ± 0.96 mm). In the maxillary frontal region 74.4% and in the mandibular frontal region 61.2% of the crestal buccal bones showed widths <1 mm. (4) Conclusions: In more than 60% of the cases, the BBT at the alveolar crest is <1 mm in maxillary and mandibular frontal regions. This anatomic data supports careful pre-surgical assessment, planning of a buccal graft, and critical selection of indication for immediate implant placement, especially in the maxillary and mandibular frontal and premolar region.

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OBJECTIVES: This randomized controlled trial aimed to compare crestal bone loss (CBL) and buccal bone thickness (BBT) around triangular cross-section neck (TN) to round neck (RN) implants retaining mandibular overdentures one year after loading, using cone beam computed tomography (CBCT). MATERIAL AND METHODS: Twenty edentulous patients receiving 40 implants with similar diameters were randomly assigned to the RN and TN groups. Clinical buccal bone thickness (CBBT) around the implants was measured with a caliper at baseline. A resonance frequency analyzer was used to measure the implant stability quotient (ISQ) at the baseline and two months after insertion. Pocket probing depths (PPD), plaque index (PI), and gingival index (GI) were also recorded at postoperative months 2, 6, and 12. CBCT was used to evaluate proximal CBL and BBT at three levels (0, -2, and -4 mm) one year after loading. RESULTS: No implant loss was observed during the follow-up period. No significant differences in CBBT, ISQ values, and scores for PPD, PI, and GI between the two groups were observed at any time (p > .05). BBT was also comparable one year after loading (p > .05). The mean ± SD proximal CBL one year after loading was 0.58 ± 0.36 mm for TN and 0.91 ± 0.59 mm for RN (p < .01). CONCLUSIONS: This study found better crestal bone preservation in the implants with the novel neck design than conventional neck design in the anterior mandible after a follow-up of one year. However, it may not be clinically noticeable.

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PURPOSE: To evaluate the buccal bone thickness of immediate implant placement with buccal bone augmentation in patients with a thin buccal plate in the esthetic zone. MATERIALS AND METHODS: Eighteen consecutive patients requiring a single tooth replacement in the anterior maxillary zone with a thin plate (<1 mm) were included and received immediate implant placement with narrow-diameter implants. Patients received buccal bone augmentation (both internal and external socket bone grafting) with deproteinized bovine bone mineral (DBBM) and an absorbable membrane. The final restoration was delivered after 8 months. Cone-beam CT scans were performed before surgery (CBCT0), immediately after surgery (CBCT1), at final restoration delivery (CBCT2), and at 1-year follow-up after the final restoration (CBCT3) to evaluate the buccal bone thickness and ridge width. A repeated measures ANOVA and Bonferroni correction for multiple comparisons were applied for statistical analysis of changes within different time points (α = 0.05). RESULTS: Fifteen of the 18 enrolled patients were available for analysis at the 1-year follow-up after final restoration. The mean buccal bone thickness at 2 mm apical to the implant-abutment junction (IAJ-2) were 3.59 mm (range: 3.04-4.58 mm), 2.79 mm (range: 2.25-3.78 mm), and 2.52 mm (range: 1.72-3.36 mm), respectively, at CBCT1, CBCT2, and CBCT3. A statistical significance was observed for buccal bone thickness change between CBCT1 and CBCT2 at IAJ-2 (F = 17.948, p = 0.001). The net gains of the ridge width from CBCT0 to CBCT1, CBCT1 to CBCT2, and CBCT2 to CBCT3 were 1.08 mm, -0.94 mm and -0.04 mm at 4 mm apical to the cementum-enamel junction, respectively. No statistical significance was observed for the change in ridge width from CBCT0 to CBCT3 (F = 10.518, p = 1.000). CONCLUSIONS: Simultaneous buccal bone augmentation may maintain a predictable buccal bone thickness for immediate implant placement in the maxillary anterior sites with a thin buccal plate (<1 mm) at 1-year follow-up after final restoration.

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OBJECTIVES: Implants with a triangular neck were recently introduced to limit peri-implant bone loss. The primary objective of this randomized controlled trial was to compare peri-implant bone changes of circular versus triangular cross-section neck implants 1 year after loading. The secondary objectives were to assess buccal hard tissue thickness changes, Pink Esthetic Score (PES), and patient satisfaction. MATERIAL AND METHODS: Thirty four patients requiring replacement of the single, intercalated missing tooth of healed site for at least 4 months in the posterior maxilla were randomized into 2 groups according to the type of implant. Immediately after surgery and 1 year after final restoration, a cone beam CT (CBCT) was performed to assess proximal bone remodeling and buccal bone thickness. Peri-implant soft tissue health, PES, and patient-reported outcome measures (PROMs) were recorded. RESULTS: No implant loss occurred within the follow-up period. The mean ± SD peri-implant proximal bone loss 1 year after loading was 0.22 ± 0.30 mm for triangular and 0.42 ± 0.67 mm for circular implants necks (p = .25). Peri-implant bone loss exceeding 2 mm was observed in a single implant in the circular neck group. Buccal bone thickness remained stable and did not differ different between the 2 groups. The peri-implant soft tissue health, PES, and patient satisfaction were also comparable. CONCLUSIONS: Within the limitations of the present study, patient clinical and radiographic outcomes did not differ between triangular and circular cross-section neck implants in the posterior maxilla.

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The biomechanics associated with buccal bone thickness (BBT) augmentation remains poorly understood, as there is no consistent agreement in the adequate BBT to avoid over-loading resorption or over-augmenting surgical difficulty. This study utilizes longitudinal clinical image data to establish a self-validating time-dependent finite element (FE)-based remodeling procedure to explore the effects of different buccal bone thicknesses on long-term bone remodeling outcomes in silico. Based upon the clinical computed tomography (CT) scans, a patient-specific heterogeneous FE model was constructed to enable virtual BBT augmentation at four different levels (0.5, 1.0, 1.5, and 2.0 mm), followed by investigation into the bone remodeling behavior of the different case scenarios. The findings indicated that although peri-implant bone resorption decreased with increasing initial BBT from 0.5 to 2 mm, different levels of the reduction in bone loss were associated with the amount of bone augmentation. In the case of 0.5 mm BBT, overloading resorption was triggered during the first 18 months, but such bone resorption was delayed when the BBT increased to 1.5 mm. It was found that when the BBT reached a threshold thickness of 1.5 mm, the bone volume can be better preserved. This finding agrees with the consensus in dental clinic, in which 1.5 mm BBT is considered clinically justifiable for surgical requirement of bone graft. In conclusion, this study introduced a self-validating bone remodeling algorithm in silico, and it divulged that the initial BBT affects the bone remodeling outcome significantly, and a sufficient initial BBT is considered essential to assure long-term stability and success of implant treatment.

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PURPOSE: To investigate the correlation of anterior overbite with the sagittal root position (SRP) and buccal bone thickness (BBT) of the maxillary anterior teeth. METHODS: Cone-beam computed tomography (CBCT) data of southern Chinese patients who underwent CBCT examinations between November 2016 and December 2016 were collected. The anterior overbite was the predictor variable while the SRP and the BBT at 4 mm apical to the cementoenamel junction (CEJ-4) and midpoint of the root of the maxillary anterior teeth were set as the primary and secondary outcome variables, respectively. All measurements were done by two calibrated examiners. Correlations between variables were analyzed by the Spearman's correlation coefficient. The significance level was set at P < 0.05. RESULTS: CBCT data of 146 patients (65 men and 81 women) with a mean age of 44.2 ± 13.4 years were analyzed, and of the 876 maxillary anterior teeth evaluated, 9.8% were presented with deep overbites. Most of roots of the anterior teeth (94.9%) were positioned against the buccal cortical plate, of which, in 63.8% of them the apex was not covered by bone along the long axis of the tooth. The mean BBT at CEJ-4 was 0.89 mm at the central incisor, 0.85 mm at the lateral incisor and 0.84 mm at the canine. The overbite was positively correlated with SRP Class I subtypes and the BBT at CEJ-4 (P < 0.05). CONCLUSION: Deep overbite was more frequently accompanied by bone fenestration in the anterior maxillary areas.

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OBJECTIVES: To evaluate the effectiveness of platelet-rich plasma (PRP) with its growth factors in minimizing the side effects of rapid maxillary expansion (RME) on the periodontal tissue of anchoring teeth using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A randomized, split-mouth clinical trial was conducted on 18 patients aged 12-16 years (14 ± 1.65) with a skeletal maxillary constriction who underwent RME using a Hyrax appliance. The sample was randomly divided into two groups: intervention and control sides. PRP was prepared and injected on the buccal aspect of supporting teeth in the intervention group. High-resolution CBCT imaging (H-CBCT) was carried out preoperatively (T0) and after 3 months of retention (T1) to study the buccal bone plate thickness (BBPT) and buccal bone crest level (BBCL) of anchoring teeth. Changes induced by expansion were evaluated using paired sample t-test (P < .05). RESULTS: Results showed that there was no significant difference in BBPT and BBCL between the two groups after RME (P > .05). The prevalence of dehiscence and fenestrations was increased at (T1) in both groups and the percentage was higher in the PRP group. CONCLUSIONS: RME induced vertical and horizontal bone loss. PRP did not minimize alveolar defects after RME.

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BACKGROUND: The aim of this study was to analyse as three dimensions the anatomical and morphometric dimensions of nasopalatine canal (NPC) in the coronal, axial and sagittal directions using cone beam computed tomography (CBCT) and to evaluate the effect of age, gender and maxillary dental status on NPC and buccal bone thickness (BBT). MATERIALS AND METHODS: In this study, CBCT data of the 619 individuals aged between 17 and 86 years were examined retrospectively with respect to dimensions and anatomic variations of the NPC and BBTs. The correlation of age, gender, and status of edentulism of anterior maxilla with all the variables were evaluated. RESULTS: The NPC and BBT showed important variability in terms of morphology and dimensions. Morphological assessment of NPC revealed that 26.17% of NPCs were conical shape, 24.71% of canals were hourglass-shaped, 16.80% of canals were cylindrical shaped, 15.83% of canals were funnel-like shaped, 11.14% of canals were banana-like shaped, and 5.33% of canals were tree branch-like shaped. Males and females showed significant differences in the length of the NPC and BBTs in the sagittal sections. There were significant differences between age and BBTs. In addition, the length of NPC and BBTs were statistically different according to dental status. CONCLUSIONS: These anatomical changes in terms of dimensional and morphological parameters revealed the importance of three-dimensional imaging. Dentists should know and consider the variations in this canal in order to avoid possible complications during anaesthesia and surgical procedures which were applied to the maxillary anterior region. More precautions should be taken during surgical procedures in females, elderly and edentulous patients.

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INTRODUCTION: The aim of this study was to determine the morphologic characteristics of mandibular first molars having 2 canals in distal roots. Interorifice distance, buccal bone thickness, and root curvature were evaluated using cone-beam computed tomography images in a Korean population. METHODS: In total, 1958 mandibular first molars were evaluated in axial, coronal, sagittal, and paraxial planes. Distal roots having 2 canals were classified according to their root and canal shapes (2 roots, 2 canals [2R2C]; 1 root, 2 canals with 2 apical foramina [1R2C(2-2)]; and 1 root, 2 canals with 1 apical foramen [1R2C(2-1)]). The distances between orifices and the distance from the apex to the buccal bone plate were measured for each root canal shape (2R2C, 1R2C[2-2], and 1R2C[2-1]). The curvature of distolingual (DL) roots was classified according to severity using 3-dimensional reconstructed images, and the direction of curvature was determined. The relationships of these characteristics to sex and side were evaluated. RESULTS: The prevalences of 2R2C, 1R2C(2-2), and 1R2C(2-1) were 25.89%, 10.32%, and 14.15%, respectively. The distances between distobuccal (DB) and DL orifices were 3.77 ± 0.74 mm for 2R2C, 3.02 ± 0.65 mm for 1R2C(2-2), and 2.44 ± 0.64 mm for 1R2C(2-1). The distances from the buccal plate to the DB canal were 3.84 ± 1.35 mm for 2R2C, 5.33 ± 1.41 mm for 1R2C(2-2), and 5.96 ± 1.63 mm for 1R2C(2-1). The distance from the buccal plate to the DL canal was 9.85 ± 1.46 mm for 2R2C, and 8.28 ± 1.50 mm for 1R2C(2-2). All distances differed significantly according to root canal configurations, and all were greater in men than women (P < .05), except for the DB-DL orifice distance in 1R2C(2-2) and the DB to buccal cortical plate distance in all root configurations (P > .05). No significant difference between the left and right sides was found (P > .05). The prevalence of most severely curved DL roots (type III) was 62.92%, and the direction was commonly toward the buccal side (69.03%). CONCLUSIONS: The prevalence of mandibular first molars having 2 canals in distal roots was more than 50% in a Korean population. Interorifice distances between DB and DL canals and distances from the apex to the buccal cortical plate differed according to root and canal numbers and shapes.

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PURPOSE: This study combines clinical investigation with finite element (FE) analysis to explore the effects of buccal bone thickness (BBT) on the morphological changes of buccal bone induced by the loaded implant. METHODS: One specific patient who had undergone an implant treatment in the anterior maxilla and experienced the buccal bone resorption on the implant was studied. Morphological changes of the bone were measured through a series of cone-beam computed tomography (CT) scans. A three-dimensional heterogeneous nonlinear FE model was constructed based on the CT images of this patient, and the in-vivo BBT changes are correlated to the FE in-silico mechanobiological stimuli; namely, von Mises equivalent stress, equivalent strain, and strain energy density. The anterior incisory bone region of this model was then varied systematically to simulate five different BBTs (0.5, 1.0, 1.5, 2.0, and 2.5mm), and the optimal BBT was inversely determined to minimize the risk of resorption. RESULTS: Significant changes in BBTs were observed clinically after 6 month loading on the implant. The pattern of bone resorption fell into a strong correlation with the distribution of mechanobiological stimuli onsite. The initial BBT appeared to play a critical role in distributing mechanobiological stimuli, thereby determining subsequent variation in BBT. A minimum initial thickness of 1.5mm might be suggested to reduce bone resorption. CONCLUSIONS: This study revealed that the initial BBT can significantly affect mechanobiological responses, which consequentially determines the bone remodeling process. A sufficient initial BBT is considered essential to assure a long-term stability of implant treatment.

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OBJECTIVES: The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. MATERIALS AND METHODS: Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. RESULTS: The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). CONCLUSIONS: For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration.

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OBJECTIVES: The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. MATERIALS AND METHODS: Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. RESULTS: The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). CONCLUSIONS: For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration.

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INTRODUCTION: The aims of this study were to evaluate the vertical and horizontal relationships between the maxillary sinus floor (MSF) and the root apices of maxillary posterior teeth with various root configurations and the distance from the root apex to the MSF and the buccal cortical plate. METHODS: Serial axial, coronal, sagittal, and paraxial cone-beam computed tomographic images of 132 Korean patients with fully erupted bilateral maxillary posterior teeth were analyzed. The vertical and horizontal relationships between the roots of maxillary posterior teeth and the MSF were determined. Distances from the apex to the MSF and the buccal bone plate were measured. The data were correlated with age, sex, side, and tooth type. RESULTS: In total, 2159 apices in 1056 teeth were evaluated. For the vertical relationships, the frequency in group 1, in which a root apex protruded into the MSF, significantly increased toward the posterior (first premolars: 1.5%, second premolars: 14.8%, first molars: 40.5%, second molars: 44.7%, P < .001). The apices of the mesiobuccal roots of the second molars were found frequently in group 1 (35.8%) and had the shortest mean vertical distance to the MSF (0.18 mm) and the thickest mean horizontal distance to the buccal cortical plate (4.99 mm) among buccal roots of 3-rooted molars (P < .001). The frequency of group 1 differed significantly by age (P < .05). No statistically significant difference was found in sex or side analysis. For the horizontal relationship between the molar roots and the MSF, most teeth were in group BP, in which the lowest point of the MSF was located centrally, relative to the roots (94.3% for first molars, 81.0% for second molars). For the first molars, no significant difference according to sex or side was found. However, the right side (P = .003) and males (P = .005) showed higher incidences for second molars. CONCLUSIONS: The data in this study highlight the close proximity between the root apex of maxillary posterior teeth and the MSF and provide estimated distances from the root apex to the buccal cortical plate. Special care must be taken in treatment planning in the maxillary posterior region.

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