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Temporary anchorage devices (TADs) are frequently applied to different anatomic areas with different protocols to increase skeletal effects and anchorage in orthodontic treatment planning. It has been reported in many literatures that primary stability for orthodontic TADs is significant for long-term survival rate. For this reason, different areas of the palatal region, which has many indications, have been widely used in the studies. In this evaluation where bone quality and thickness are important, density, bone thickness, and fractal dimension (FD) on cone beam computed tomography (CBCT) will provide more predictable clinical results. The aim of this study was to evaluate bone thickness, density, and FD in the palatal region of the first, and second premolars, and first molars. There was a remarkable difference (p < 0.05) between the parameters of FD, thickness and density of bone in the identified areas in the palatal region. In terms of thickness and FD, the 1st premolar region had significantly higher values than the other regions (p < 0.05). In terms of density, the values in the right 1st molar and right 1st premolar regions were significantly higher (p < 0.05). The 1st premolar region is an ideal site for placement of palatal TADs. CBCT-assisted preliminary evaluation of FD value, bone density, and thickness may increase clinical success when selecting the location of TADs to be applied to the palatal bone. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the infrazygomatic crest (IZC) bone and develop guidelines for the optimum placement of orthodontic miniscrew implants (OMSIs) along the distobuccal root of the permanent maxillary first molar. Methods: Bone thickness of the IZC region of 50 young adults (25 males and 25 females) aged 18-30 years were evaluated using cone-beam computed tomography images. The infrazygomatic bone thickness along the distobuccal root of the permanent maxillary first molar was assessed at various insertion angles (40° to 75° i.r.t the maxillary occlusal plane) with an increment of 5°. Student’s t-test was used to compare the IZC bone thickness and height at the orthodontic miniscrew insertion site for males and females on the right and left sides. Results: The bone thickness of the IZC region above the distobuccal root of the permanent maxillary first molar was estimated between 4.39±0.25 mm and 9.03±0.45 mm for insertion angles from 40° to 75° to the maxillary occlusal plane. The corresponding OMSI insertion heights were 17.71±0.61 mm to 13.69±0.75 mm, respectively, above the maxillary occlusal plane. There were statistically significant gender and side-wise variations in bone thickness at the IZC area and insertion height. Conclusion: The safe position for OMSI placement at the IZC was 13.69-16 mm from the maxillary occlusal plane with an insertion angle between 55° and 75°. These parameters provide the optimum placement of OMSIs along the distobuccal root of the permanent maxillary first molar.

Objective: The present study investigated bone remodelling in the upper and lower incisor regions depending on the inclination pattern during the alignment phase of orthodontic treatment (OT). Materials and Methods: This prospective clinical study included 71 patients undergoing OT without premolar extraction. Cone beam computed tomography scans were taken before and after the alignment phase and the changes in the inclination, alveolar bone height (ABH) and bone thickness (BT) at levels 2, 3, 4, 6, 8 and 9 mm starting from the cementoenamel junction (CEJ) were determined. Results: Teeth were divided into 'Retroinclination' (lingual crown inclination <0°), 'Proclination‐low' (buccal crown inclination between 0° and 5°), or 'Proclination‐high' (buccal crown inclination >5°). The alignment phase of OT resulted in ABH loss. The highest ABH loss in the maxilla was observed on the buccal side in the 'Proclination‐high' and was 0.71 mm. ABH loss by 1.1 mm was observed in the mandible on the lingual side in the 'Retroinclination' group. The most significant changes in BT by up to 2 mm were observed at levels 6, 8 and 9 mm and these changes exhibited a moderate to strong correlation with the alterations in the inclination of individual incisors. At levels 2, 3 and 4 mm, the highest decrease in BT by up to 0.83 mm was observed on the palatal side of upper incisors in the 'Proclination‐high' group. Conclusion: The direction and amount of tooth inclination partially determine changes in the bone parameters during the alignment phase. [ABSTRACT FROM AUTHOR]

There were only a few studies investigating the effect of sagittal root position (SRP), sagittal root angle (SRA), and buccal bone thickness (BBT) on peri-implant tissues using the socket shield technique (SST). This retrospective case series aimed to evaluate the SRP, SRA, and BBT in socket shield cases and examine the effect of these anatomical factors on the peri-implant tissue phenotype and bone level. Data from 27 patients (14 women, 13 men) treated with SST in the maxillary esthetic region between July 2019 and September 2021 were included. Clinical indices (modified plaque and bleeding indices, probing depth, keratinized mucosa width, mucosal thickness) and periapical radiographic recordings (marginal bone level) taken immediately after permanent prosthesis placement and 1 year later were used. Cone beam computerized tomography images were used to examine BBT, SRP, and SRA before implant placement and horizontal and vertical bone levels before implant placement and 1 year after prosthetic rehabilitation. The data were divided into groups based on BBT (<1 and ≥1 mm) and SRA values (<10° and ≥10°). There were no significant differences in 1-year clinical factors between the SRA <10° and SRA ≥10° groups. However, higher vertical bone loss was found in the SRA ≥10° group (P =.01, d = 0.53). There were no significant differences in clinical or radiographic factors between the BBT <1 mm and BBT ≥1 mm groups. In conclusion, BBT showed no significant effect on tissue phenotype and bone level, but SRA affected bone level in socket shield cases. [ABSTRACT FROM AUTHOR]

Positional plagiocephaly is a deformational cranial flattening frequently treated in pediatric neurosurgical practice. Positional maneuvers and orthotic helmet therapy are preferred therapeutic options for moderate-to-severe forms. Treatment response seems to be age-dependent. Nevertheless, predictive data are vague, and cost-efficiency might be a limiting factor for treatment. The purpose of this study was to investigate the early predictive value of sonographic parameters on the efficacy of orthotic helmet therapy through the assessment of changes in skull shape and correlation of the parameters with caliper cephalometry values and with age. A consecutive cohort of 49 patients < 10 months of age, undergoing orthotic helmet therapy for positional plagiocephaly, was recruited prospectively. The authors routinely assessed the patency of the lambdoid sutures by ultrasound and the following additional skull parameters were measured: suture width, adjacent full bone thickness, adjacent cortical bone thickness and occipital angle. Caliper cephalometric values, as well as demographic and clinical data were collected. Retrospective data analysis showed an inverse relation between both cortical and full skull bone thickness and early treatment efficacy, defined by a reduction in the occipital angle. The improvement of sonographic parameters correlated with the development of cranial caliper cephalometry values. In conclusion, the sonographic assessment of skull bone thickness is a safe and cost-effective tool to predict the early efficacy of orthotic helmet therapy in positional plagiocephaly and might, therefore, help the clinician to foresee the potential evolution of the deformity. [ABSTRACT FROM AUTHOR]

Objective To explore the distribution and difference of bone thickness in the infrazygomatic crest (IZC) in adolescents at different eruption stages of the maxillary second molar and provide guidance for placement of orthodontic IZC miniscrew. Methods Cone beam CT scans of 110 adolescents with normal occlusion were assessed. According to the eruption stage of the maxillary second molar, the subjects were divided into 3 groups of S1 (44 cases), S2 (30 cases), and S3 (36 cases). The horizontal base plane (HB) in this study was defined as a horizontal axial section with the mesiobuccal cusps of the left maxillary first molar on. Two coronal slices of interest were selected which passing through the apex of mesiobuccal (MB) and distobuccal (DB) roots of the left maxillary first molar respectively. In both of the two coronal slices, the buccal bone thickness was measured at 13 (HB13), 15 (HB15), 17 (HB17) mm above the HB plane at a gingival inclination of 60°. The measurement differences of bone thickness between MB and DB, and among different heights were evaluated, and the differences among S1, S2, and S3 groups in each simulated paths were compared. Distributions of measurements were reported as colormaps. Results The IZC bone thickness of DB was thicker than MB at HB13 and HB15 in the 3 groups.The higher the insertion height, the smaller the bone thickness (P<0.05). Bone thickness decreased from S1 to S2 to S3 at HB13 and HB15. The maximum bone thickness (5.20 mm) was observed at HB13 in DB, and the minimum bone thicness (1.90 mm) was observed at HB17 in DB. Conclusion The thickest bone in IZC of the three groups located at HB13 in DB of the maxillary first molar, and the bone thickness decreases with the increase of the insertion height. The later the eruption stage of the maxillary second molar, the less bone thickness in the IZC region and the operation difficulty might increase. [ABSTRACT FROM AUTHOR]

Objectives: To assess whether filter and contrast adjustments can improve the accuracy of CBCT in measuring the buccal bone thickness (BBT) adjacent to dental implants by reducing blooming artifacts. Materials and methods: Homogeneous bone blocks with peri-implant BBT of 0.3 mm, 0.5 mm, and 1 mm were scanned using the Orthophos SL system. Three dentists measured the BBT in 234 CBCT scans under different settings of contrast adjustments and ‘Sharpen’ filter activation. Additionally, implant diameter measurements were taken to assess blooming artifact expression. The differences between tomographic and actual measurements of BBT and implant diameter [(CBCT - actual) * 100 / actual] were subjected to Mixed ANOVA (α = 0.05). Results: The group with the thinnest BBT (0.3 mm) had the greatest difference between tomographic and actual measurements (79.9% ± 29.0%). Conversely, the 0.5 mm (36.1% ± 38.4%) and 1 mm (29.4% ± 12.3%) groups exhibited lower differences (p < 0.05). ‘Sharpen’ filter activation reduced blooming expression since it resulted in a lower difference for implant diameter (p < 0.05), but it did not influence BBT measurements (p = 0.673). Contrast settings had no impact on BBT (p = 0.054) or implant diameter measurements (p = 0.079). Conclusion: Although filter activation reduced blooming artifacts, neither filter nor contrast adjustments improved the accuracy of CBCT in measuring peri-implant BBT; actual BBT influenced this task. Clinical relevance: When assessing the peri-implant buccal bone plate in the CBCT system studied, dental surgeons may find it beneficial to adjust contrast and apply filters according to their preferences, since such adjustments were found to have no adverse effects on the diagnostic accuracy of this task. The use of the ‘Sharpen’ filter may lead to improved representation of implant dimensions. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the infrazygomatic crest (IZC) bone and develop guidelines for the optimum placement of orthodontic miniscrew implants (OMSIs) along the distobuccal root of the permanent maxillary first molar. Methods: Bone thickness of the IZC region of 50 young adults (25 males and 25 females) aged 18-30 years were evaluated using conebeam computed tomography images. The infrazygomatic bone thickness along the distobuccal root of the permanent maxillary first molar was assessed at various insertion angles (40° to 75° i.r.t the maxillary occlusal plane) with an increment of 5°. Student's t-test was used to compare the IZC bone thickness and height at the orthodontic miniscrew insertion site for males and females on the right and left sides. Results: The bone thickness of the IZC region above the distobuccal root of the permanent maxillary first molar was estimated between 4.39±0.25 mm and 9.03±0.45 mm for insertion angles from 40° to 75° to the maxillary occlusal plane. The corresponding OMSI insertion heights were 17.71±0.61 mm to 13.69±0.75 mm, respectively, above the maxillary occlusal plane. There were statistically significant gender and side-wise variations in bone thickness at the IZC area and insertion height. Conclusion: The safe position for OMSI placement at the IZC was 13.69-16 mm from the maxillary occlusal plane with an insertion angle between 55° and 75°. These parameters provide the optimum placement of OMSIs along the distobuccal root of the permanent maxillary first molar. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to assess the shape and size of the nasopalatine canal (NPC) using cone beam computed tomography (CBCT) in Iranian patients.Materials and Methods: This cross-sectional descriptive study investigated 285 CBCT scans of the anterior maxilla, obtained from patients in Rafsanjan, Iran. The shape of the nasopalatine canal was categorized as banana (twisted), funnel (diverging towards the oral or nasal cavity), cylindrical, and hourglass. The length and diameter of the canal were measured using multiplanar images. Labial bone thickness was recorded at two points: A at the incisive foramen and B at the foramen of Stenson. Kruskal-Wallis and chi-square tests were used for analysis at P

Objective: This study aimed to assess the shape and size of the nasopalatine canal (NPC) using cone beam computed tomography (CBCT) in Iranian patients. Materials and Methods: This cross-sectional descriptive study investigated 285 CBCT scans of the anterior maxilla, obtained from patients in Rafsanjan, Iran. The shape of the nasopalatine canal was categorized as banana (twisted), funnel (diverging towards the oral or nasal cavity), cylindrical, and hourglass. The length and diameter of the canal were measured using multiplanar images. Labial bone thickness was recorded at two points: A at the incisive foramen and B at the foramen of Stenson. Kruskal-Wallis and chi-square tests were used for analysis at P<0.05. Results: The hourglass shape was the dominant canal model in the sample. The mean canal length and the mesiodistal and labiopalatal diameter (at incisive foramen) were 11.17 ± 2.5 mm, 3.6 ± 1.2 mm, and 3.4 ± 1.2 mm, respectively. Moreover, the mean bone thickness at points A and B were 6 ± 1.4 and 8 ± 4.4 mm. A significant difference was found among different canal shapes concerning bone thickness at point B (P=0.01) and labiopalatal width of the canal (P<0.001). There was a direct and significant relationship between the patient's age and the mesiodistal and labiopalatal widths of the NPC (P=0.001 and P=0.015, respectively). Conclusion: Concerning the age-related and race-related variations in nasopalatine canal morphology, CBCT scans are recommended for accurate evaluation before implant placement or orthodontic retraction in the anterior maxilla. [ABSTRACT FROM AUTHOR]

Abstract Aim The purpose of this study was to evaluate the effect of the density and the thickness of the cortical and the cancellous bone at selected inter-radicular areas in subjects with different facial growth patterns using cone beam computed tomography (CBCT) in order to choose the optimal area for miniscrew insertion. Materials and methods From 150 CBCT scans, 45 scans were included in the study. The subjects were categorized into three groups based on their skeletal growth pattern according to SN-GoMe angle and facial height index. Cortical and cancellous bone density and thickness were measured at the selected inter-radicular areas. Results Compared to the other two groups, the hyperdivergent group had thinner cortical bone in the anterior region of the maxilla between the central and the lateral incisors on the buccal side at 4 mm from the alveolar crest (P-value: 0.012) and on the palatal side at 7 mm from the alveolar crest (P-value: 0.030). Cancellous bone density values in these areas were higher in subjects with hypodivergent and hyperdivergent growth pattern. Furthermore, in hyperdivergent group less dense cortical bone in the posterior region of the maxilla on the palatal side between the second premolar and the first molar (p-value: 0.020) and on the buccal side between the first molar and the second molar (p-value: 0.038 & 0.047) was observed. No significant differences were found in the mandible between the three groups. No significant differences were found between the male and the female subjects. Conclusion Hyperdivegents presented thinner cortical bone in the anterior of the maxilla between the central and the lateral incisors. Less dense cortical bone was found between maxillary second premolar and first molar on the palatal side and also between the maxillary first molar and the second molar on the buccal side in this group too. Normal showed higher density values in the posterior of the maxilla compared to the other two groups. No significant differences were found among three groups in mandible.

Positional plagiocephaly is a deformational cranial flattening frequently treated in pediatric neurosurgical practice. Positional maneuvers and orthotic helmet therapy are preferred therapeutic options for moderate-to-severe forms. Treatment response seems to be age-dependent. Nevertheless, predictive data are vague, and cost-efficiency might be a limiting factor for treatment. The purpose of this study was to investigate the early predictive value of sonographic parameters on the efficacy of orthotic helmet therapy through the assessment of changes in skull shape and correlation of the parameters with caliper cephalometry values and with age. A consecutive cohort of 49 patients < 10 months of age, undergoing orthotic helmet therapy for positional plagiocephaly, was recruited prospectively. The authors routinely assessed the patency of the lambdoid sutures by ultrasound and the following additional skull parameters were measured: suture width, adjacent full bone thickness, adjacent cortical bone thickness and occipital angle. Caliper cephalometric values, as well as demographic and clinical data were collected. Retrospective data analysis showed an inverse relation between both cortical and full skull bone thickness and early treatment efficacy, defined by a reduction in the occipital angle. The improvement of sonographic parameters correlated with the development of cranial caliper cephalometry values. In conclusion, the sonographic assessment of skull bone thickness is a safe and cost-effective tool to predict the early efficacy of orthotic helmet therapy in positional plagiocephaly and might, therefore, help the clinician to foresee the potential evolution of the deformity.

Aim: The purpose of this study was to evaluate the effect of the density and the thickness of the cortical and the cancellous bone at selected inter-radicular areas in subjects with different facial growth patterns using cone beam computed tomography (CBCT) in order to choose the optimal area for miniscrew insertion. Materials and methods: From 150 CBCT scans, 45 scans were included in the study. The subjects were categorized into three groups based on their skeletal growth pattern according to SN-GoMe angle and facial height index. Cortical and cancellous bone density and thickness were measured at the selected inter-radicular areas. Results: Compared to the other two groups, the hyperdivergent group had thinner cortical bone in the anterior region of the maxilla between the central and the lateral incisors on the buccal side at 4 mm from the alveolar crest (P-value: 0.012) and on the palatal side at 7 mm from the alveolar crest (P-value: 0.030). Cancellous bone density values in these areas were higher in subjects with hypodivergent and hyperdivergent growth pattern. Furthermore, in hyperdivergent group less dense cortical bone in the posterior region of the maxilla on the palatal side between the second premolar and the first molar (p-value: 0.020) and on the buccal side between the first molar and the second molar (p-value: 0.038 & 0.047) was observed. No significant differences were found in the mandible between the three groups. No significant differences were found between the male and the female subjects. Conclusion: Hyperdivegents presented thinner cortical bone in the anterior of the maxilla between the central and the lateral incisors. Less dense cortical bone was found between maxillary second premolar and first molar on the palatal side and also between the maxillary first molar and the second molar on the buccal side in this group too. Normal showed higher density values in the posterior of the maxilla compared to the other two groups. No significant differences were found among three groups in mandible. [ABSTRACT FROM AUTHOR]

Purpose: Due to smaller bone thickness, young children with conductive or mixed hearing loss or single-sided deafness were previously most commonly treated with a percutaneous osseointegrated bone-anchored hearing aid (BAHA) or an active middle-ear implant. While the BAHA increases the risk of implant infections, skin infection, overgrowth of the screw or involvement of the implant in head trauma, middle-ear implant surgery involves manipulation of the ossicles with possible risk of surgical trauma. These complications can be omitted with transcutaneous bone conduction implant systems like the MED-EL Bonebridge system. The purpose of this study was to analyze whether the second generation of the Bonebridge (BCI 602) that features a decreased implant thickness with a reduced surgical drilling depth can be implanted safely in young children with good postoperative hearing performance. Methods: In this study, 14 patients under 12 years were implanted with the second generation of the Bonebridge. Preoperative workup comprised a CT scan, an MRI scan, pure tone audiometry, or alternatively a BERA (bone conduction, air conduction). Since children under 12 years often have a lower bone thickness, the CT was performed to determine the suitability of the temporal bone for optimal implant placement using the Otoplan software. Results: All patients (including three under the age of five) were successfully implanted and showed a good postoperative hearing performance. Conclusion: With adequate preoperative workup, this device can be safely implanted in children and even children under 5 years of age and allows for an extension of indication criteria toward younger children. [ABSTRACT FROM AUTHOR]

Objective To assess the bone thicknesses of the infrazygomatic crest in the adult patients with different vertical skeletal patterns of skeletal classⅠmalocclusion based on cone-beam computed tomography (CBCT), and to provide the basis for the choice of clinical treatment methods for the orthodontists. Methods A total of 90 adult patients with skeletal class I malocclusion were selected and divided into low angle group, average angle group, and high angle group, and there were 30 patients in each group. The buccal bone thickness of the patients at different vertical levels and proximal, distal and mesial levels were detected on the CBCT images and the effective bone volume was measured at buccal alveolar bone thickness ≥ 3 mm with the 50°, 60°and 70° implantation angles. Results In different vertical sections, except for the proximal mesiobuccal root level of the maxillary first molar (U6mb), the buccal alveolar bone thickness was increased gradually from the top of the alveolar ridge to the root side (P<0.05) . At different proximal, distal and mesial levels, the buccal bone thickness of the patients was gradually increased from the proximal to the distal mesial direction in all levels except U6mb (P<0.05) . The maximum buccal bone thickness of the patients was 11 mm from the top of the alveolar ridge at the proximal mesiobuccal root of the maxillary second molar (U7mb) ； the minimum buccal bone thickness was 7 mm from the top of the alveolar ridge at U6mb.There was significant difference in the buccal bone thickness of the patients with different vertical bone facial types (P<0.05), the buccal bone thickness of the patients in low angle group was higher than those in average angle group and high angle group (P<0.05), and the buccal bone thickness of the patients in average angle group was higher than that in high angle group (P<0.05) .Among the patients in low angle group, there were significant differences in bone thicknesses between the distal mesiobuccal root of the maxillary first molar and the proximal mesiobuccal root of the maxillary second molar (U6db-U7mb) at from the top of the alveolar crest was 7 mm, at U7mb when the distance from the top of the alveolar crest was 7 mm and 9 mm, at U6mb-U6db when the distance from the top of the alveolar crest was 11 mm at three angles (P<0.05) .The bone thickness was ≥6 mm at U6db-U7mb, when the distance from the top of the alveolar crest was 7 mm at three angles, and when the distance from the top of the alveolar crest was 9 mm at 70° at U7mb.Among the patients in average angle group, there were significant differences in the bone thicknesses between U6db-U7mb at 9 mm from the top of the alveolar crest, U7mb at 9 mm and 11 mm from the top of the alveolar crest at three implantation angles, and the bone thickness ≥6 mm at U7mb when the distance from the top of the alveolar crest at three angles was 7 mm and at U7mb when the distance from the top of the alveolar crest was 9 mm at 70° (P<0.05). Among the patients in high angle group, there were significant differences in bone thickness between U6db-U7mb 11 mm from the top of the alveolar ridge and U7mb 11 mm from the top of the alveolar ridge at three implantation angles (P<0.05) . The thicknesses of bone implantation at different angles could be ranked as follows, 70°>50°>60° in all dimensions. Conclusion There are differences in the buccal bone thickness in the zygomatic crest area among the adult patients with different vertical facial bone patterns. The patients in low angle group have more options for the implantation sites, while the patients in high angle group are more prone to maxillary sinus perforation.Therefore, when placing dental implants and designing orthodontic treatment plans in this area, the vertical facial bone pattern should be taken into consideration. [ABSTRACT FROM AUTHOR]

Aim and Objective: The aim of the study was to compare the full-depth bone thickness and the cortical bone thickness in the infrazygomatic crest (IZC) region above the mesiobuccal (MB) root of maxillary first molar and second molar and thus find the ideal site for the placement of IZC screw. Materials and Methods: Pretreatment cone-beam computed tomography images of 30 orthodontic patients were collected and IZC bone thickness and cortical bone thickness were measured above the MB root of maxillary first and second molar at an angle of 70° to the molar occlusal plane. Measurements were done on both right and left sides. Independent sample t test was done to compare the bone thickness between the right and left sides and also to compare the bone thickness above the first and the second molar. Results: Mean bone thickness at the IZC region of 5.48 ± 2.2 mm and 7.78 ± 2.35 mm and a cortical bone thickness of 2.24 ± 0.46 mm and 2.13 ± 0.46 mm was obtained above the MB root of maxillary first molar and second molar, respectively. IZC bone thickness was significantly higher above the second molar than above the first molar (P <.001), whereas there was no significant difference in the cortical bone thickness measured on both the sites (P =.22). Conclusion: Significantly higher IZC bone thickness was noted above the MB root of the maxillary second molar, which may ensure better stability and safety of the miniscrew. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to retrospectively determine the prevalence of severe external root resorption in maxillary incisors during fixed orthodontic treatment and to evaluate the possible predisposing factors.Methods: The treatment records of 7000 patients who had been treated between 1990 and 2019 at the Department of Orthodontics Faculty of Dentistry Marmara University were examined, and a total of 120 patients with severe root resorption in at least one of their upper incisors were identified. The following data were retrieved from the patients' records and radiographs: gender, root morphology, overjet, overbite, treatment modality (extraction, non-extraction), treatment duration, buccal and palatal alveolar bone thickness for the maxillary incisors, and amount of movement of the incisal root apices and incisal edges. These data from a group of 90 patients with severe root resorption were compared with the data from a control group of 90 patients with minimal root resorption. The Chisquare test, the Mann–Whitney U-test, and the independent t-test were used for statistical analysis.Results:The prevalence of severe external root resorption was 3.23%, and the results demonstrated significant difference between the groups for the variables of treatment modality (extractions), treatment duration, thickness of the alveolar bone, and amount of incisor movement at the end of the treatment.Conclusion: It can be concluded that extractions, increased treatment duration, thin alveolar bone, and excessive incisor movement represent risk factors for severe root resorption in maxillary incisors following orthodontic treatment.

Introduction: Open gingival embrasure (OGE) is a common complication in adults following clear aligner therapy and the influence of gingival or alveolar bone biotype on OGE is of great concern. Unfortunately, due to the limited number of patients with clearaligner therapy and the clinical methods to distinguish the gingival biotype of patients being invasive, it is difficult to carry out clinical studies on the gingival or alveolar bone biotype of the OGE. In the meanwhile, the detailed biomechanics of the occurrence of OGE remains unknown. The goal of this study was to establish a new model to simulate the virtual space region, namely, the OGE region, to investigate the relationship between alveolar bone biotype and the occurrence of OGE, and explore potential biomechanical factors related to OGE.Methods: The OGE region in the interproximal space was established using a filler with a very low modulus of elasticity (1 × 10−6 MPa). To illustrate the biomechanics of OGE more exhaustively, a line was created at the top of the alveolar crest along the proximal tooth root. FEA was then used to analyze the biomechanics of the surrounding tissues, the OGE region and the line at the top of the alveolar crest along the proximal tooth root of the central incisor under two different labial bone thicknesses (thick and thin) with an axial inclination of 80°, 90° and 100°.Results: During intrusion of the incisors in clear aligner therapy, as inclination increased or bone tissue became thinner, the stress in the surrounding tissues [tooth root, alveolar crest, and periodontal ligament (PDL)] was greater. In the OGE region and interproximal alveolar crest, the strain increased with increasing inclination and labial bone thinning. The results from the line at the top of the alveolar crest along the proximal tooth root showed more detailed biomechanics: In all groups, stress and strain were focused on the mesial-labial alveolar crest. Interestingly, our results also demonstrated that when OGE occurs, other complications may arise, including root resorption and bone dehiscence.

Objective: The aim of this study was to retrospectively determine the prevalence of severe external root resorption in maxillary incisors during fixed orthodontic treatment and to evaluate the possible predisposing factors. Methods: The treatment records of 7000 patients who had been treated between 1990 and 2019 at the Department of Orthodontics Faculty of Dentistry Marmara University were examined, and a total of 120 patients with severe root resorption in at least one of their upper incisors were identified. The following data were retrieved from the patients' records and radiographs: gender, root morphology, overjet, overbite, treatment modality (extraction, non-extraction), treatment duration, buccal and palatal alveolar bone thickness for the maxillary incisors, and amount of movement of the incisal root apices and incisal edges. These data from a group of 90 patients with severe root resorption were compared with the data from a control group of 90 patients with minimal root resorption. The Chisquare test, the Mann-Whitney U-test, and the independent t-test were used for statistical analysis. Results: The prevalence of severe external root resorption was 3.23%, and the results demonstrated significant difference between the groups for the variables of treatment modality (extractions), treatment duration, thickness of the alveolar bone, and amount of incisor movement at the end of the treatment. Conclusion: It can be concluded that extractions, increased treatment duration, thin alveolar bone, and excessive incisor movement represent risk factors for severe root resorption in maxillary incisors following orthodontic treatment. [ABSTRACT FROM AUTHOR]

Abstract Background Maxillary skeletal expanders (MSE) is effective for the treatment of maxillary transverse deformity. The purpose of the study was to analyse the palatal bone thickness in the of MSE implantation in patients with skeletal class III malocclusion. Methods A total of 80 adult patients (40 males, 40 females) with an average angle before treatment were divided into two groups, the skeletal class III malocclusion group and the skeletal I malocclusion group, based on sagittal facial type. Each group consisted of 40 patients, with a male to female ratio of 1:1. A cone-beam computed tomography scanner was employed to obtain DICOM data for all patients. The palatal bone thickness was measured at 45 sites with MIMICS 21.0 software, and SPSS 22.0 software was employed for statistical analysis. The bone thickness at different regions of the palate in the same group was analysed with one-way repeated measures ANOVA. Fisher’s least significant difference-t method was used for the comparison of pairs, and independent sample t test was employed to determine the significance of differences in the bone thickness at the same sites between the two groups. Results Palatal bone thickness was greater in the middle region of the midline area (P

The objective of this retrospective study was to evaluate buccal bone and gingival thickness measurements obtained from cone beam computed tomographic (CBCT) images of maxillary anterior teeth with and without metal posts. A convenience sample of 71 CBCT images of healthy maxillary anterior teeth and 61 CBCT images of maxillary anterior teeth with a metal post were selected from a database. Eight tomographic measurements (4 bone thicknesses and 4 gingival thicknesses) were performed in the parasagittal section of each tooth, perpendicular to the tooth axis. The Mann-Whitney U test was used to compare these thicknesses, and the Spearman correlation coefficient was calculated for correlation of age with sex. Statistically significant differences were observed for almost all measurements (P < 0.05); the CBCT images of teeth with metal posts displayed lower bone thickness values and higher gingival thickness values. No statistically significant correlations were observed between the thickness measurements and age. However, significantly higher bone thickness values were observed in men (P < 0.05). Cone beam computed tomographic images of teeth with metal posts showed differences in mean bone and gingival measurements compared to teeth without metal posts, suggesting a possible interference of metal artifacts. [ABSTRACT FROM AUTHOR]

Anchorage is one of the most important consideration in the field of orthodontics to achieve a desired tooth movement. In order to eliminate the undesirable side effects such as anchorage loss, skeletal anchorage systems such as mini-implants have been introduced in orthodontics. Aim: To evaluate the bone thickness of the infrazygomatic crest in different cervical vertebrae maturation index (CVMI) and to compare it between male and female subjects, by using cone beam computerized tomography (CBCT) imaging. Materials and Methods: A retrospective study was conducted using CBCT images of 60 patients in the age group of 8-25 years. Cervical vertebra maturation was analyzed using Hassel--Farmann index and divided into 6 groups (n = 10/group). The infrazygomatic crest was divided into horizontal and vertical planes. The horizontal plane passed through the most inferior border of the zygomatic process of maxilla and the vertical plane passed through the most anterior point of the infratemporal fossa parallel to midsagittal plane. Five parallel lines were drawn at 2 mm interval in both horizontal and vertical planes (HB+2, HB+4, HB+6, HB+8, and HB+10) (V-2, V-4, V-6, V-8, and V-10). The bone thickness was measured at the point of intersection of these lines. Results: According to Kruskal--Wallis analysis, statistically significant difference in infrazygomatic crest (IZC) bone thickness was seen in various CVMI stages (P = .001). Maximum bone thickness was 11 mm and minimum bone thickness was 1 mm. No significant difference was observed between male and female populations. Conclusion: Thus, the superolateral area in infrazygomatic crest is the most appropriate site for miniscrew insertion in all age groups. [ABSTRACT FROM AUTHOR]

Background and Objectives: Corticotomy-facilitated orthodontics is an approach that can be useful in treating complex orthodontic cases and that could enhance the rate of tooth movement. The aim of this study was to evaluate the changes that occurred in the buccal cortical bone and at the root level after an orthodontic treatment when corticotomy was used, in Romanian patients. Materials and Methods: After dividing the subjects into two groups (maxillary and mandibular corticotomy), based on CBCT, measurements were made of the thickness of the cortical buccal bone at the cervical, median and apical level, and of the root length at T0 (before corticotomy) and T1 (6 months after surgery). Several tests were used for statistical analysis of the data. Results: In the maxillary arch, the bone thickness measured after corticotomy in males was 0.64 mm at the cervical level, 0.53 mm at the medial level and 0.30 mm in the apical area. In females, the values were 0.46 mm (cervical), 0.37 mm (medial) and 0.36 mm (apical). In the lower arch, the values obtained for these three regions were 0.37 mm, 0.30 mm and 0.37 mm for males and 0.58 mm, 0.32 mm and 0.43 mm for female subjects. All values were statistically significant. The root length for the lower teeth at T0 was 11.98 ± 2.24 mm at T0 and 11.97 ± 2.24 mm at T1. For the upper teeth, the root length at T0 was 13.83 ± 2.28 mm and 13.81 ± 2.28 mm. Conclusions: Comparing the measurements, it was observed that the biggest changes in the cortical bone were at the cervical level. In the maxillary arch, the most significant modifications were registered at the canines and the level of the first premolars, and in the lower arch at the incisors level. The measured root resorption of the teeth was considered to be statistically insignificant. [ABSTRACT FROM AUTHOR]

Abstract Background The bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries. The aim of this study was to systematically measure the bicortical bone thickness, the ramus dimensions and the position of the lingula. The measurements were tested on significant correlations to the patients’ parameters. Methods Based on CBCT scans 150 rami were reconstructed as 3D polygon surfaces. An anatomical grid was adapted to the ramus surface to mark the bone thickness measurement points and to achieve comparability between the measurements on different mandibles. The bone thickness, ramus height, ramus width and the gonion angle were measured. A cluster analysis was performed with these parameters to identify clinically relevant groups with anatomical similarities. Results The median distribution of the bone thickness was calculated and visualized in a pseudo-colour map. The mean ramus height was 44.78 mm, the mean width was 31.31 mm and the mean gonion angle was 124.8°. The average distance from the lingula to the dorsal tangent was 53% of the total width and its distance to the caudal tangent was 65% of the total height. Significant correlations between the bone thickness and the ramus proportions could be identified. Age and sex had no significant influence on the mean bone thickness. The measured rami could be divided into two groups by cluster analysis. Conclusion The dimensions of the human mandibular ramus can be determined from 3D reconstructed surface models from CBCT scans. Measurements could be made comparable by applying an anatomically oriented grid. A cluster analysis allowed the differentiation of two groups with different bone thickness distributions and geometries, which can be used for the optimization of osteosynthesis systems and their precision of adaptation to different ramus morphologies.

Background/Aim: Dental implant stabilities are essential to prevent implant loss. The purpose of the study is to appraise the physical properties, bone density, and bone thickness of dental implants and the effects of the implant locations on stability. Materials and Methods: Thirty-six patients participated in the study at the Harran University Periodontology Department (between 2019 and 2020). Of these patients, 19 patients were female, 17 patients were male, and the average age of patients was 48.21 years. Patients who underwent dental implant surgery were contained in the study. A total of 127 dental implants were placed using standard surgical protocols. The specific transducer compatible with implant system was fixed to the implant body by means of an abutment using a screw. The implant stability quotient (ISQ, Osstell™) values were determined for each implant 4, 8, and 12 weeks after surgery. Results: As a result of the statistical analysis, the values of the ISQ taken in the mandible region were higher in the 4, 8, and 12 weeks compared to the values of the ISQ values obtained from the maxilla region. Statistically significant differences were also found between these values (P < 0.05). Conclusion: We found that implants with a long and wide width represented higher ISQ values and stability compared to shorter and narrower implants. Higher values were found in the mesiodistal direction compared to the buccolingual and buccopalatal directions, and in the mandible compared to the maxilla. This situation increases the stability in places where bone density and bone thickness are higher.

Orthodontists should know variation in thickness of infrazygomatic crest region according to maturation status of patients. Therefore, it is of interest to evaluate the thickness of bone at infrazygomatic crest region and to correlate the thickness of bone with cervical vertebrae maturation index (CVMI) incorporating CBCT.A retrospective analysis of 120 patients' CBCT scans60 of them male and 60 female-was carried out. The thickness of the bone was determined at five locations. Using CBCT, the cervical vertebral maturation was created and the Hassel-Farmann index was used for analysis. A lone researcher conducted all of the measurements. Bone thickness of infrazygomatic arch at all five locations was found to increase as the maturation stage progressed from initiation stage to maturation stage. Then there was decrease in the bone thickness in completion stages compared to maturation stage. The thickness of bone at infrazygomatic arch is significantly correlated with CVM stages as determined by CBCT., (© 2024 Biomedical Informatics.)

Diploic veins are part of the circulatory system of the head. They transport venous blood and cerebrospinal fluid and are housed in diploic channels (DCs). DCs are highly variable in terms of their position, extension, and size. These parameters were hypothesized to be related to the variations in cranial vault thickness (CVT). For the first time, we analyzed the spatial relationship between CVT and DCs in a sample of eight H. neanderthalensis and H. sapiens cranial fossils. Using micro-CT scanning data, we constructed color maps of the CVT and visually inspected whether the regional thickness variation was associated with the morphology and distribution of the DC branches. The results showed that when regional bone thickness was below a certain threshold, no DCs or scattered small DC branches were present. Larger DC branches appeared only when the thickness exceeded the threshold. However, once the threshold was reached, further increases in thickness no longer resulted in more or larger DCs. This study also found that our sample of H. neanderthalensis and H. sapiens have different distribution patterns in thin areas, which may affect how their DCs connect with different branches of the middle meningeal vessels. This preliminary study provides evidence for the discussion on the interaction between the cranium, brain, and blood vessels. Future research should include more hominin fossils to better document the variation within each species and possible evolutionary trends among hominin lineages., (© 2023 The Authors. The Anatomical Record published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)

Purpose: The present study aims to evaluate the superior semicircular canal (SSC) bone thickness and radiological patterns in relation to age and gender in a Turkish population using cone beam computed tomography (CBCT). Methods: A total of 450 temporal bones were evaluated in the study by two examiners. The radiological patterns of SSC were categorized as follows: dehiscent, papyraceous, normal, thick and pneumatised patterns. The bone thickness of SSCs were measured. Results: The mean bone thickness of the SSC for females was 1.079 ± 0.8 mm. For males, the mean bone thickness was 0.952 ± 0.6 mm. There was no significant difference between males and females for the mean bone thickness of the SSC. (p > 0.05) The normal pattern was found in 258 temporal bones (57.3%). Seventy-two cases (16%) were defined as "papyraceous pattern"; 23 cases (5.1%) were defined as "thick pattern" and 42 cases (9.3%) were defined as "pneumatised pattern". SSC dehiscence was determined in 55 cases (12.2%). There was no significant difference between radiological patterns for age groups and gender (p > 0.05). Conclusion: There was no significant relationship between SSC bone thickness with age and gender. The radiological patterns of SSC were not associated with age and gender. Radiologists evaluating the head and neck region for various reasons should be aware of these structures and report not only the SSC dehiscence but also the papyraceous pattern. [ABSTRACT FROM AUTHOR]

Background and Objective: Quantitative assessment of bone density and thickness in computed-tomography images offers great potential for preoperative planning procedures in robotic ear surgery.Methods: We retrospectively analyzed computed-tomography scans of subjects undergoing cochlear implantation (N = 39). In addition, scans of Thiel-fixated ex-vivo specimens were analyzed (N = 15). To estimate bone mineral density, quantitative computed-tomography data were obtained using a calibration phantom. The temporal bone thickness and cortical bone density were systematically assessed at retroauricular positions using an automated algorithm referenced by an anatomy-based coordinate system. Two indices are proposed to include information of bone density and thickness for the preoperative assessment of safe screw positions (Screw Implantation Safety Index, SISI) and mass distribution (Column Density Index, CODI). Linear mixed-effects models were used to assess the effects of age, gender, ear side and position on bone thickness, cortical bone density and the distribution of the indices.Results: Age, gender, and ear side only had negligible effects on temporal bone thickness and cortical bone density. The average radiodensity of cortical bone was 1,511 Hounsfield units, corresponding to a bone mineral density of 1,145 mg HA/cm3. Temporal bone thickness and cortical bone density depend on the distance from Henle's spine in posterior direction. Moreover, safe screw placement locations can be identified by computation of the SISI distribution. A local maximum in mass distribution was observed posteriorly to the supramastoid crest.Conclusions: We provide quantitative information about temporal bone density and thickness for applications in robotic and computer-assisted ear surgery. The proposed preoperative indices (SISI and CODI) can be applied to patient-specific cases to identify optimal regions with respect to bone density and thickness for safe screw placement and effective implant positioning.

Background: Maxillary skeletal expanders (MSE) is effective for the treatment of maxillary transverse deformity. The purpose of the study was to analyse the palatal bone thickness in the of MSE implantation in patients with skeletal class III malocclusion. Methods: A total of 80 adult patients (40 males, 40 females) with an average angle before treatment were divided into two groups, the skeletal class III malocclusion group and the skeletal I malocclusion group, based on sagittal facial type. Each group consisted of 40 patients, with a male to female ratio of 1:1. A cone-beam computed tomography scanner was employed to obtain DICOM data for all patients. The palatal bone thickness was measured at 45 sites with MIMICS 21.0 software, and SPSS 22.0 software was employed for statistical analysis. The bone thickness at different regions of the palate in the same group was analysed with one-way repeated measures ANOVA. Fisher's least significant difference-t method was used for the comparison of pairs, and independent sample t test was employed to determine the significance of differences in the bone thickness at the same sites between the two groups. Results: Palatal bone thickness was greater in the middle region of the midline area (P < 0.01), while the thickness in the middle and lateral areas in both groups was generally lower (P < 0.001). The bone in the anterior, middle, and posterior regions of the two groups became increasingly thin from the middle area toward the parapalatine region. The palatal bone was significantly thinner in the area 9.0 mm before the transverse palatine suture in the midline area, 9.0 mm before and after the transverse palatine suture in the middle area, and 9.0 mm after the transverse palatine suture in the lateral area. Conclusion: The palatal bone was thinner in patients with class III malocclusion than in patients with class I malocclusion, with significant differences in some areas. The differences in bone thickness should be considered when MSE miniscrews are implanted. The anterior and middle palatal areas are safer for the implantation of miniscrews, while the thinness of the posterior palatal bone increases the risk of the miniscrews falling off and perforating. [ABSTRACT FROM AUTHOR]

Background and Objectives: Corticotomy-facilitated orthodontics is an approach that can be useful in treating complex orthodontic cases and that could enhance the rate of tooth movement. The aim of this study was to evaluate the changes that occurred in the buccal cortical bone and at the root level after an orthodontic treatment when corticotomy was used, in Romanian patients. Materials and Methods: After dividing the subjects into two groups (maxillary and mandibular corticotomy), based on CBCT, measurements were made of the thickness of the cortical buccal bone at the cervical, median and apical level, and of the root length at T0 (before corticotomy) and T1 (6 months after surgery). Several tests were used for statistical analysis of the data. Results: In the maxillary arch, the bone thickness measured after corticotomy in males was 0.64 mm at the cervical level, 0.53 mm at the medial level and 0.30 mm in the apical area. In females, the values were 0.46 mm (cervical), 0.37 mm (medial) and 0.36 mm (apical). In the lower arch, the values obtained for these three regions were 0.37 mm, 0.30 mm and 0.37 mm for males and 0.58 mm, 0.32 mm and 0.43 mm for female subjects. All values were statistically significant. The root length for the lower teeth at T0 was 11.98 ± 2.24 mm at T0 and 11.97 ± 2.24 mm at T1. For the upper teeth, the root length at T0 was 13.83 ± 2.28 mm and 13.81 ± 2.28 mm. Conclusions: Comparing the measurements, it was observed that the biggest changes in the cortical bone were at the cervical level. In the maxillary arch, the most significant modifications were registered at the canines and the level of the first premolars, and in the lower arch at the incisors level. The measured root resorption of the teeth was considered to be statistically insignificant.

The conventional shield technique can reduce the absorption of labial fasciculate bone after immediate implantation of anterior teeth, but it is highly demanded by the operator. When implants are implanted, it is easy to loosen the remaining teeth on the labial side, resulting in failure of the operation. OBJECTIVE: To evaluate the clinical effects of a modified socket shield technique for immediate implant and immediate restoration and flapless immediate implant and immediate restoration in maxillary aesthetic area. METHODS: Sixty patients were randomly chosen with failing tooth from September 2016 to August 2017 in Department of Stomatology in Affiliated Hospital of Binzhou Medical College. The samples included 33 males and 27 females, aged from 20 to 81 years. There were 38 cases of central incisor and 22 cases of lateral incisor. The patients were randomly divided into two groups. The 30 patients in the experimental group received a modified socket shield technique for immediate implant and immediate restoration. The 30 patients in the control group received conventional flapless immediate implant and immediate restoration. During return visit after 1 year, the retention rate of the implant and pink esthetic score were recorded; the buccal bone thicknesses of the implant neck and roots 2, 4 mm were observed by cone beam computed tomography; and the patient satisfaction was analyzed. The study was approved by the Medical Ethics Committee of the Affiliated Hospital of Binzhou Medical College(Hospital Ethics Approval Number: 2019-LW-025). RESULTS AND CONCLUSION: (1) The survival rate of both groups was 100%. (2) One year after operation, the pink esthetic score of the experimental group was higher than the preoperative score and that in the control group(P < 0.05). The pink esthetic score of the control group was lower 1 year after surgery than preoperative score(P < 0.05). (3) One year after operation, the buccal bone thickness loss of the implant neck and roots 2, 4 mm in the experimental group was lower than that in the control group(P < 0.05). (4) The satisfaction rate of the experimental group was higher than that in the control group(P < 0.05). (5) The results showed that the modified socket shield technique used for immediate implant and immediate restoration can maintain the buccal bone thickness and improve the aesthetic effect. [ABSTRACT FROM AUTHOR]

Purpose: Variation of dimensions of the nasopalatine canal and anterior maxillary bone thickness vary in relation to age, gender, edentulism, and ethnicity; thorough knowledge with regard to these landmarks is of vital importance prior to surgical procedures such as implant placement and local anesthesia in the anterior maxilla. Cone beam computerized tomography (CBCT) aids in accurate treatment planning in such situations. Subjects and Methods: A total of 300 participants were selected by the inclusion and exclusion criteria. CBCT was performed with Hyperion X9 CBCT Scanner. Images were reconstructed from the CBCT data using NNT image reconstruction software and visualized using multi-planar resolution screen. The dimensions of the nasopalatine foramen (NPF), the incisive canal (IC) and foramen, and anterior maxillary bone thickness were measured. Results: The mean diameter of NPF was found to be 3.27 mm, incisive foramen (IF) was 3.62 mm, IC was 2.12 mm. The average length of the IC was 10.66 mm. The IF was located at a mean distance of 13.81 mm away from the most anteroinferior point of the cortical plate of the labial bone of the maxilla. The anterior maxillary bone was the thickest at the nasal spine level (10.94 mm), and was the narrowest at lower labial alveolus (7.16 mm). The average anterior maxillary bone thickness was found to be 8.36 mm. Conclusion: Within the limitations of the study, it was found that found that gender and age are important factors that affected the characteristics of the IC and the amount of bone anterior to it.

To determine whether there was a correlation between patients' bone thickness and time spent in orthodontic treatment. The secondary aim was to study the influence of Angle classification, extraction treatment, and age on overall treatment duration. In this retrospective study, records of 971 orthodontic patients from two centers were reviewed and 500 subjects were included after imposing inclusion/exclusion criteria. The Mental Index was used to determine patients' bone density. For the Mental Index, a line perpendicular to the inferior border of the mandible was drawn on a panoramic radiograph so that it intersected the inferior border of the mental foramen. The mandibular cortical thickness was measured along this line. Two-sample t-test or a chi-square test, followed by multiple linear regression, were used to identify the factors affecting treatment duration. Mandibular cortical thickness was negatively associated with treatment time for all subjects (P <.05). After adjusting for covariables, it remained significant for center-1, but non-significant for center-2 subjects. Angle Class II and Class III malocclusion, extraction therapy, and age had significant positive correlations with treatment duration (P <.05). There is a negative correlation between the mandibular cortical thickness and orthodontic treatment duration. An extraction treatment plan and treatment of Angle Class II and Class III malocclusions significantly increase the duration of orthodontic treatment. Additionally, patients over 12 years of age have shorter treatment times compared to patients under 12 years of age. [ABSTRACT FROM AUTHOR]

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Background: The bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries. The aim of this study was to systematically measure the bicortical bone thickness, the ramus dimensions and the position of the lingula. The measurements were tested on significant correlations to the patients' parameters. Methods: Based on CBCT scans 150 rami were reconstructed as 3D polygon surfaces. An anatomical grid was adapted to the ramus surface to mark the bone thickness measurement points and to achieve comparability between the measurements on different mandibles. The bone thickness, ramus height, ramus width and the gonion angle were measured. A cluster analysis was performed with these parameters to identify clinically relevant groups with anatomical similarities. Results: The median distribution of the bone thickness was calculated and visualized in a pseudo-colour map. The mean ramus height was 44.78 mm, the mean width was 31.31 mm and the mean gonion angle was 124.8°. The average distance from the lingula to the dorsal tangent was 53% of the total width and its distance to the caudal tangent was 65% of the total height. Significant correlations between the bone thickness and the ramus proportions could be identified. Age and sex had no significant influence on the mean bone thickness. The measured rami could be divided into two groups by cluster analysis. Conclusion: The dimensions of the human mandibular ramus can be determined from 3D reconstructed surface models from CBCT scans. Measurements could be made comparable by applying an anatomically oriented grid. A cluster analysis allowed the differentiation of two groups with different bone thickness distributions and geometries, which can be used for the optimization of osteosynthesis systems and their precision of adaptation to different ramus morphologies. [ABSTRACT FROM AUTHOR]

Our aim was to investigate the bone thickness at the site of titanium miniplates inserted to retain nasal prostheses. We studied 13 patients who had had titanium miniplates inserted for retention of nasal prostheses with a total of 60 titanium bone screws. A trajectory along each bone screw was segmented in fused computed tomographic (CT) data. Bone thickness was measured along this trajectory on the preoperative CT. The median bone thickness at the positions of the screws implanted on the frontal process of the maxillary bone was 1.4 (range 0.2–6.9) mm (mean 1.8). The median (range) values for men and women were 1.4 (0.2–6.9) mm and 1.3 (0.2–3.3) mm, respectively. The thickest bone was at the cranial part of the frontal process of the maxilla with a median of 2.0 (range 0.3–4.1) mm. However, differences in sex and position were not significant. None of the implant miniplates lost osseointegration. Despite the low bone stock at the lateral aspect of the pyriform aperture, survival of implanted titanium miniplates was 100% in this study group. [ABSTRACT FROM AUTHOR]

Hyperostosis frontalis interna (HFI) represents an abnormality of the frontal cranial bone that is characterized by bilateral, nodular thickening of its inner lamina and may sometimes be associated with neuropsychiatric symptoms such as headaches and depression. The aim was to assess prevalence, sex and age differences of HFI and frontal bone thickness by means of MRI. This retrospective study included 908 subjects who were divided into male and female groups and further subdivided into three groups, youngest (≤45 years), middle-aged (46-65 years) and the oldest group (>65 years). The thickness of the frontal bone was measured on the T2-weighted axial images at the top level of the lateral ventricles as a mean from both sides. We considered 10mm or thicker frontal bone as HFI. The total prevalence of HFI was 8.1%, with a more frequent occurrence in women (p<0.05). In males, there was no difference in the frontal bone thickness between different age groups (p>0.05), while in females we found differences between the youngest and the oldest group, and also between the middle-aged and the oldest group (p<0.05). The female respondents had a thicker frontal bone, which was statistically significant only in the oldest group (p<0.001). Frontal bone thickness was age-dependent only in women (Spearman's Rho 0.11; p≤0.01). In women, unlike in men, there is an age-related progression of HFI with increasing prevalence, with 16.4% occurrence in the oldest group. [ABSTRACT FROM AUTHOR]

Objective: To assess the impact of various local pathologies on facial alveolar bone dimensions at tooth sites. Materials and methods: Cone-beam computed tomography images of 60 patients were analyzed. Healthy teeth and teeth with local pathologies (i.e., endodontically treated, periodontally diseased teeth, and teeth with periapical lesions) were included. The thickness of the facial alveolar bone was measured at five locations: (1) the bone crest (W0), (2) 25% (W25), (3) 50% (W50), (4) 75% (W75) of the distance from the bone crest to the root apex (A), and (5) in the A region (W100). The results were considered statistically significant at p < 0.0008 (adjustment according to the statistical correction for multiple testing). Results: A total of 1174 teeth (707 healthy and 467 with the local pathologies) were assessed. Periodontally diseased maxillary premolars and anterior teeth in the mandible in the W0 position, as well as maxillary molars in the W25 position, tended to have a lower facial bone thickness when compared to the healthy teeth (0.68 mm vs. 0.84 mm, p = 0.008; 0.47 mm vs. 0.55 mm, p = 0.004; and 1.27 mm vs. 1.72 mm; p = 0.009, respectively). In contrast, the observed tendency pointed towards thicker facial bone wall for the periodontally diseased mandibular anterior teeth in the W50 position (0.74 vs. 0.52, p = 0.001). Healthy maxillary molars tended to display a thicker facial alveolar bone compared to the teeth with local pathologies in the W25, W50, and W75 positions (p = 0.001, p = 0.005, and p = 0.004, respectively). Conclusions: The present analysis has indicated that local pathologies are commonly associated with a compromised socket morphology. Clinical relevance: The facial bone thickness was particularly reduced at periodontally diseased teeth, which may challenge implant therapy. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the cortical bone resorption of fibular bone after maxillary reconstruction with a fibula free flap. A total of 35 patients with maxillary defects that were repaired using a fibula flap (62 fibula segments) between January 2011 and January 2016 were enrolled. Computed tomography (CT) images taken 1 week and 1 year postoperative were used to evaluate cortical bone resorption. The 62 fibula segments were measured on four different surfaces in the CT images. At 1 week, the thickness of the cortical bone was 2.57 ± 0.58 mm, 2.72 ± 0.46 mm, 3.84 ± 0.98 mm, and 4.36 ± 0.90 mm for the exterior, interior, superior, and inferior sides, respectively. At approximately 1 year, the cortical bone thickness was significantly reduced to 2.00 ± 0.65 mm (P < 0.01), 2.25 ± 0.60 mm (P < 0.01), 3.37 ± 0.90 mm (P < 0.01), and 2.96 ± 0.84 mm (P < 0.01) for the exterior, interior, superior, and inferior sides, respectively. The cortical bone thickness of fibular bone is significantly reduced 1 year after the restoration of maxillary defects with a fibula free flap, most significantly on the inferior side. [ABSTRACT FROM AUTHOR]

To evaluate the measurement accuracy of hard-tissue thicknesses adjacent to dental implants with different thread designs on images obtained from cone beam computed tomography (CBCT) using an in vitro model. On 4 × 13-mm implant, the neck of the implant was designed with micro-threads, and the apical part was covered by macro-threads; these implants were placed in a vinyl polysiloxane block that mimicked hard-tissue. Models were prepared with various thicknesses of 2.0, 1.0, 0.5 and 0.3 mm adjacent to the dental implant. Each model was scanned using CBCT, and the thickness of the cortical bone from the outer surface of the micro-threads and macro-threads were recorded. Ground sections were prepared, and the thickness was measured with electronic calipers as the gold standard (GS) measurement. CBCT measurements of the micro-thread surface were consistently underestimated compared to the GS measurement when the thickness of the hard-tissue-mimicking material was ≤1.0 mm. In comparison, CBCT measurements of the macro-thread surface closely approximated the standard measurement, except when the thickness of the hard-tissue-mimicking material was 0.3 mm. The mean percentage errors from the standard measurement for the 2.0-, 1.0-, 0.5-, and 0.3-mm thickness groups were 4.8%, 16.4%, 37.8%, and 92.6%, respectively, for the micro-thread group, and were 0.6%, 2.9%, 9.5%, and 40.8%, respectively, for the macro-thread group. Within the limitations of this study, we conclude that CBCT may not produce sufficient resolution for thin sections of hard tissue-mimicking materials adjacent to micro-thread surfaces. [ABSTRACT FROM AUTHOR]

Objective: To noninvasively determine the relationship between the thickness of the buccal bone and attached gingiva of the maxillary premolars. Material and Methods: 128 maxillary premolars in 32 patients were assessed for measurement of buccal bone thickness and corresponding attached gingival thickness at 3 mm apical to cemento‐enamel junction. Buccal bone thickness was measured on cone‐beam computed tomography scans and attached gingival thickness by ultrasound unit. Pearson's correlation coefficient was calculated to assess the correlation between buccal bone and attached gingival thickness at each tooth type. Results: The mean buccal bone thickness at the maxillary premolars was 1.07 mm. The 1st premolars had a buccal bone thickness < 1 mm at 68% of all sites, and the 2nd premolars had a buccal bone thickness of 1.0‐2.0 mm at 32% of all sites. The 1st premolars had a gingival thickness > 1.2 mm at 55% of all sites, and the 2nd premolars had a gingival thickness of 1.1‐1.3 mm at 45% of all sites. The correlation between buccal bone and attached gingival thickness was moderately positive (r = 0.406; P < .001). Conclusions: The relationship between buccal bone thickness and gingival thickness is independent of each other in the maxillary right first premolar, whereas a moderate correlation with a dependent relation exists in the maxillary right second premolar, maxillary left first premolar, and maxillary left second premolar. Clinical Significance: Soft tissue and hard tissue associated with volumetric changes in maxillary premolar region can be unfavorable for both aesthetic and implant placement. In fact this study highlighted the relationship between the thickness of attached gingiva and corresponding buccal bone in maxillary premolar region so to enable for proper planning of implant therapy following extraction. [ABSTRACT FROM AUTHOR]

Objectives: To identify the optimal cutoff value in Hounsfield units (HU) of maxillary sinus (MS) opacity and bone thickness (neo-osteogenesis) of MS as radiological predictors for mycetoma.Methods: One hundred and sixty-four patients, including 59 patients with unilateral MS mycetoma, 31 with unilateral odontogenic maxillary sinusitis, 44 with chronic rhinosinusitis and 30 with rhinitis, who underwent sinus or turbinate surgery were recruited. The bone thickness, HU of the MS posterolateral wall and sinus opacity were evaluated using computed tomography scan.Results: The bone thickness of the MS posterolateral wall in the mycetoma group was significantly higher than that in the odontogenic sinusitis and chronic rhinosinusitis (CRS) groups (p < 0.0001). The HU of the sinus opacity in the mycetoma group were significantly higher than those in the odontogenic and CRS groups (p < 0.0001). An optimal cutoff HU of sinus opacity >101.17 yielded a sensitivity of 96.6 and specificity of 100% for the diagnosis of MS mycetoma. An optimal cutoff of bone thickness >0.305 cm yielded a sensitivity of 84.7 and specificity of 60% for the diagnosis of MS mycetomas.Conclusions: The radiographic density measurement of MS opacification has a high predictive value for the diagnosis of MS mycetoma while radiographic neo-osteogenesis has not. [ABSTRACT FROM AUTHOR]

Background: There is lack of studies regarding preservation and possible changes in BBT at dental implants. Purpose: To assess, on cone beam computer tomograms, the presence of bone at the time of tooth extraction in the maxillary esthetic region and the mean buccal bone thickness 1 month and 1 year after final restoration placement in patients with large bony defects. Material and Methods: In a cohort study, patients were selected presenting a failing tooth with a large bony defect (test group [n = 20]: large bony defect, immediate placed implant and delayed provisionalization). Results were compared with a group in which patients presented a failing tooth without or with a small bony defect: (control group [n = 20]: without or small bony defect, immediate placed implant and delayed provisionalization). Cone beam computer tomograms were made preoperatively, and 1 month and 1 year after placement of the restoration, and buccal bone thickness was analyzed. Results: In both groups approximately 1 mm of buccal bone thickness was present after 1 month and 1 year, without a significant difference between the groups. Conclusion: In patients with large bony defects at a failing tooth it was possible to create a bone layer buccally of the implant and this bone layer remained stable during a 1‐year follow‐up; there were no significant differences between thickness of buccal bone at 1 month and 1 year in patients with large buccal bony defects and patients without or with small bony defects. [ABSTRACT FROM AUTHOR]