The morphology of alveolar bone of the mandibular second and third molars in skeletal Class III patients.

OBJECTIVES: To investigate the alveolar bone morphology of the mandibular second and third molars in skeletal Class III patients from a buccolingual direction. METHODS: Sixty skeletal Class III patients were recruited. The alveolar bone width, buccal cortical bone thickness and lingual cortical bone thickness were measured in five planes from mesial to distal and at five depths from gingival to root. The effects of the gender of the patients, the second molar lingual inclination and the third molar on alveolar bone width and cortical bone thickness were evaluated. To explore the effect of third molar extraction on alveolar bone morphology, the measurements before and after third molar extraction were compared. RESULTS: The impacted third molar had significantly greater alveolar bone width and thicker buccal cortical bone at the cervical third of the molar, while the erupted third molar had greater alveolar bone width at the apical third. Three weeks after third molar extraction, these advantages would weaken owing to the reconstruction of the alveolar bone. Patients with lingually inclined molar were observed to own thicker lingual cortical bone. Males tended to have greater alveolar bone width, but no significant differences were shown in this study. CONCLUSIONS: The growth of the third molar and the second molar lingual inclination affect the alveolar bone morphology of the mandibular second and third molars significantly, but gender has trivial effects on the morphology. The alveolar bone morphology of the mandibular second and third molars would change 3 weeks after third molar extraction.

Cortical bone thickness on preoperative CT scans as predictor of bone quality in distal femur fractures: a retrospective study in Caucasians.

AIM: Distal femur fractures (DFF) are rare, but associated with high complication rates and mortality, particularly in patients with osteoporosis. To improve preoperative assessment, we analyzed if cortical bone thickness on CT and AP radiographs is associated with clinical parameters of bone quality. METHODS: Retrospective single-center study of adult patients presenting at a level-one trauma center, with a DFF between 2011 and 2020. Clinical parameters for bone quality, such as age, sex, body mass index (BMI), energy impact level of trauma, and known history of osteoporosis, were assessed. Mean cortical bone thickness (CBTavg) on AP radiograph was determined using a previously published method. Cortical thickness on CT scan was measured at 8 and 14 cm proximal to the articular surface of the lateral condyle. RESULTS: 71 patients (46 females) between 20 and 100 years were included in the study. Cortical thickness determined by CT correlated significantly with CBTavg measurements on AP radiograph (Spearman r = 0.62 to 0.80; p < 0.001). Cortical thickness was inversely correlated with age (Spearman r = - 0.341 to - 0.466; p < 0.001) and significantly associated with trauma impact level and history of osteoporosis (p = < 0.001). The CT-based values showed a stronger correlation with the clinical parameters than those determined by AP X-ray. CONCLUSION: Our results showed that cortical thickness of the distal femur correlates with clinical parameters of bone quality and is therefore an excellent tool for assessing what surgical care should be provided. Interestingly, our findings indicate that cortical thickness on CT is more strongly correlated with clinical data than AP radiograph measurements.

The Matsudai Knee Osteoarthritis Survey showed the longitudinal changes of knee phenotypes in alignment and structure during 23-28 years.

PURPOSE: The longitudinal changes in alignment and structure, including the joint line and cortical bone thickness (CBT) of the femur and tibia, and knee phenotype in patients with knee osteoarthritis (OA) remain unknown. The aim of this retrospective study was to clarify the longitudinal changes in matched healthy subjects. METHODS: The follow-up Matsudai Knee Osteoarthritis Survey was administered between 23 and 28 years. This study included 285 healthy knees from 235 females with an average age of 53 ± 6 years at baseline. The non-OA individuals, with an average age of 79 ± 4 years, were divided into three groups at baseline according to their follow-up radiographic results [the non-OA (n = 52), early OA (n = 131), and advanced OA groups (n = 102)]. Changes in alignment, joint line, CBT, and knee phenotype were assessed at baseline and at follow-up using standing anteroposterior radiographs. RESULTS: This study showed significant varus changes in the alignment (p < 0.001) and tibial and femoral joint line parameters (p < 0.05) in the OA group. Decreased CBT and increased mediolateral CBT ratios were observed in all groups (p < 0.001). The knee phenotypes in the OA groups were changed to varus angles, especially in the alignment and tibial joint line. CONCLUSIONS: The longitudinal changes of knee phenotypes in alignment and structure (CBT and joint line) from baseline to follow-up were shown in the OA groups. In addition, alignment and tibial structural factors at baseline are useful in predicting the incidence of knee OA in daily practice. LEVELS OF EVIDENCE: III.

New classification for bone type at dental implant sites: a dental computed tomography study.

OBJECTIVE: This study proposed a new classification method of bone quantity and quality at the dental implant site using cone-beam computed tomography (CBCT) image analysis, classifying cortical and cancellous bones separately and using CBCT for quantitative analysis. METHODS: Preoperative CBCT images were obtained from 128 implant patients (315 sites). First, measure the crestal cortical bone thickness (in mm) and the cancellous bone density [in grayscale values (GV) and bone mineral density (g/cm3)] at the implant sites. The new classification for bone quality at the implant site proposed in this study is a "nine-square division" bone classification system, where the cortical bone thickness is classified into A: > 1.1 mm, B:0.7-1.1 mm, and C: < 0.7 mm, and the cancellous bone density is classified into 1: > 600 GV (= 420 g/cm3), 2:300-600 GV (= 160 g/cm3-420 g/cm3), and 3: < 300 GV (= 160 g/cm3). RESULTS: The results of the nine bone type proportions based on the new jawbone classification were as follows: A1 (8.57%,27/315), A2 (13.02%), A3 (4.13%), B1 (17.78%), B2 (20.63%), B3 (8.57%) C1 (4.44%), C2 (14.29%), and C3 (8.57%). CONCLUSIONS: The proposed classification can complement the parts overlooked in previous bone classification methods (bone types A3 and C1). TRIAL REGISTRATION: The retrospective registration of this study was approved by the Institutional Review Board of China Medical University Hospital, No. CMUH 108-REC2-181.

Insertion and removal torque of dental implants placed using different drilling protocols: An experimental study on artificial bone substitutes.

PURPOSE: The aim of this in vitro study was to measure the insertion and removal torque values of dental implant replicas inserted into artificial bone blocks using different surgical burs and drilling protocols. MATERIALS AND METHODS: Four types of artificial, polyurethane bone blocks were used with different thicknesses (1 and 2 mm) and densities (soft-1 mm, soft-2 mm, dense-1 mm, and dense-2 mm) of the simulated cortical and cancellous bone, respectively. Each bone construct was drilled with Straumann and Densah drills in both clockwise and counterclockwise directions for a total of 16 experimental conditions. For every scenario, 38 implant replicas were inserted and then removed after 1 min. Outcomes of interest were the insertion and removal torque values which were recorded by a torque meter. ANOVA and Tukey HSD tests were used to assess differences across each combination of drill, direction, and bone type. RESULTS: Densah counterclockwise registered statistically greater values for both insertion and removal torque, followed by Densah clockwise, Straumann counterclockwise, and Straumann clockwise. Increasing insertion and removal torque values were progressively reported for bone type (soft-1 mm, dense-1 mm, soft-2 mm, and dense-2 mm). The mean values of insertion and removal torque were significantly different (p < 0.05) across the four bone types, different burs, and with the two drilling modalities. CONCLUSIONS: Densah bur resulted in significantly greater values of torque compared to the Straumann drills for all the experimental conditions. The thickness of the cortical layer and the counterclockwise drilling direction play a significant role in determining the implant insertion torque.

People living with HIV have low trabecular bone mineral density, high bone marrow adiposity, and poor trabecular bone microarchitecture at the proximal femur.

People living with HIV (PLWH) have increased risk of osteoporosis and fractures. We assessed the proximal femur of PLWH and age-matched seronegative controls using quantitative computed tomography and magnetic resonance imaging. Results suggest that the trabecular compartment is compromised at fracture-prone regions in the proximal femur of PLWH. INTRODUCTION: People living with HIV (PLWH) have increased risk of osteoporosis and fractures. However, studies assessing the main determinants of bone strength in the proximal femur exclude this vulnerable population. We assessed the proximal femur of 40 PLWH and 26 age-matched seronegative controls using quantitative computed tomography and magnetic resonance imaging. METHODS: We examined cortical volumetric bone mineral density (Ct.vBMD), trabecular vBMD (Tb.vBMD), cortical thickness (Ct.Th), bone marrow adiposity (BMA), and trabecular number, separation, and bone volume fraction. Parametric comparisons between the two groups were made for the femoral head, femoral neck, trochanter, and total hip using linear regression adjusting for several covariates, including metrics of body composition. In addition, we investigated the associations of BMA with Tb.vBMD and trabecular microarchitecture with Spearman's rank partial correlations. RESULTS: PLWH had lower Tb.vBMD and deteriorated trabecular microarchitecture in the femoral neck, trochanter and total hip, and elevated BMA in the femoral head, femoral neck, and total hip. Ct.vBMD and Ct.Th were not significantly different between the two groups. BMA was significantly associated with lower Tb.vBMD and deteriorated trabecular microarchitecture in both groups albeit at different femoral regions. CONCLUSIONS: Our findings suggest that the trabecular, and not the cortical, compartment is compromised in the proximal femur of PLWH. The observed impairments in fracture-prone regions in PLWH indicate lower femoral strength and suggest higher fracture risk. The inverse associations of BMA with trabecular bone density and microarchitecture quality agree with findings at other anatomic sites and in other populations, suggesting that excess BMA possibly due to a switch from the osteoblast to the adipocyte lineage may be implicated in the pathogenesis of bone fragility at the femur in PLWH.

Medial patellofemoral ligament is a part of the vastus medialis obliquus and vastus intermedius aponeuroses attaching to the medial epicondyle.

PURPOSE: This study aimed to investigate the bony surface characteristic of the femoral attachment of the medial patellofemoral ligament (MPFL) and the correlation between the relevant layered structures, including muscular aponeurosis and the joint capsule, which contribute to patellofemoral joint (PFJ) stability. METHODS: The morphology of the medial aspect of the medial condyle using micro-computed tomography and analysed cortical bone thickening in 24 knees was observed. For the macroscopic and histological analyses, 21 and 3 knees were allocated, respectively. The Kruskal-Wallis one-way analysis of variance test with Dunn post hoc testing was performed for statistical analysis. RESULTS: At the level of the adductor tubercle, there were no significant differences in cortical bone thickness. At the level of the medial epicondyle (MEC), cortical bone thickness was considerably greater than that in other areas of the medial condyle (mean ± standard deviation, 0.60 ± 0.20 mm; p < 0.0001). Macroscopic analysis revealed that the deep aponeurosis of the vastus medialis obliquus and the tendinous arch of the vastus intermedius distally formed the composite membrane and adjoined to the joint capsule to firmly attach to MEC, which was located at 41.3 ± 5.7 mm posterior and 14.2 ± 3.1 mm superior to the joint cartilage. Histological analysis showed a composite membrane and adjoining capsule attached to MEC via fibrocartilage. CONCLUSION: MPFL could be interpreted as part of the deep aponeurosis of the vastus medialis obliquus (VMO) and the tendinous arch of the vastus intermedius, which combined with the joint capsule to attach to MEC. The cortical bone thickening indicated that the tensile stresses were loaded on MEC in aged cadavers. Involvement of VMO and vastus intermedius aponeuroses in restored graft of MPFL could utilise the dynamic stability of surrounding muscles to mimic a native structure.

Cortical bone thickness and bone density effects on miniscrew success rates: A systematic review and meta-analysis.

OBJECTIVE: To systematically review the effects of cortical bone thickness (CBT) and bone mass density (BMD) on miniscrew success rates. METHODS: MEDLINE, the Cochrane Library and Scopus were searched up to June 2020. Of a total of 5734 articles, seven studies were finally selected for the review. RESULTS: The overall mean success rate weighted by the number of miniscrews was 87.21% (89.87% in the maxilla and 79.24% in the mandible). There was a significantly higher success rate for miniscrews placed in the maxilla compared with those in the mandible (P < .05). CBT showed small positive effect on the success rate of the miniscrews although it failed to reach a statistical significance. The cortical BMD had a minimal effect on the success of the miniscrews. The cancellous BMD demonstrated a very strong effect on the success of the miniscrews in the maxilla, whereas it showed a moderately negative effect in the mandible. LIMITATIONS: Because of the small number and clinical heterogeneity of the included studies, the results should be interpreted with caution. Further randomized clinical studies with a large sample size are recommended.

Detection and measurements of apical lesions in the upper jaw by cone beam computed tomography and panoramic radiography as a function of cortical bone thickness.

OBJECTIVES: In the current literature, cone beam computed tomography (CBCT) seems to be more accurate in detecting apical lesions (AL) than two-dimensional radiographs. Cortical bone thickness might have an influence on AL visibility. Therefore, the purpose of the study was to directly compare the diagnostic accuracy of panoramic radiography (PANO) and CBCT in detecting AL in the upper jaw and determine the influence of cortical bone thickness on AL visibility. MATERIALS AND METHODS: Anonymised digital images of 351 patients who received a CBCT image and a panoramic radiograph within 90 days were examined for AL in the upper jaw. The analysis was conducted by a trained examiner and reviewed by an expert in dental radiology. Further, the dimensions of AL and cortical bone thickness in the region affected by AL were measured to determine their influence on visibility. Statistical analysis was carried out by means of statistical software (IBM SPSS 25; Armonk, NY, USA). RESULTS: The mean age of the patients was 58.9 years with an almost equal gender distribution. A total of 2223 teeth in the upper jaw were included in the final analysis. CBCT detected AL on 144 teeth (6.5%), of which only 23 were also visible on a PANO. The difference between both methods was significant (p < 0.001). The dimensions of AL measured within a PANO were approximately twice as high as those measured by CBCT. However, the difference was not significant (p ≥ 0.005). Cortical bone thickness had no influence on AL visibility. CONCLUSIONS AND CLINICAL RELEVANCE: Panoramic radiographs are unsuitable for a reliable diagnosis of AL in the upper jaw, while CBCT leads to a better visualisation of AL. Bone thickness has no significant influence on AL visibility with either imaging method.

Association Between Increased Concavity of Maxillary Labial Alveolar Bone and Decreased Labial Cortical Bone Thickness: A Cone Beam Computed Tomography Aided Retrospective Cohort Study.

PURPOSE: To assess whether an increased concavity of maxillary labial alveolar bone is related to labial thickness of cortical bone in that area and to the presence of extraoral manifestations in the philtrum. MATERIALS AND METHODS: Cone beam computed tomography images along with intra- and extraoral photographic images of 50 Caucasian female patients, age range 18 to 65 years (mean: 37 years), previously evaluated for implant treatment were assessed by three experienced prosthodontists. Patients were divided into two groups (A and B), according to the presence or absence of a horizontal groove at the philtrum area. Mann-Whitney U test (α = 0.05) was performed to reveal any statistical differences regarding the angle of the maxillary labial concavity and the labial thickness of the alveolar cortical bone between the two groups. RESULTS: The mean angle of the maxillary concavity in group A was 127.76° while in group B it was 137.12°. The mean thickness of the labial cortical wall of the dental, interdental, and edentulous areas of the 8 anterior teeth for group A were: 0.41 mm, 0.61 mm, and 0.46 mm, respectively; and for group B were: 0.52 mm, 0.72 mm, and 0.56 mm, respectively. The Mann-Whitney U test (α = 0.05) revealed a statistically significant difference for both the angle (p = 0.008) but not for the thickness of the bone (p = 0.062). CONCLUSIONS: According to the results of this study an increased maxillary labial concavity was associated with reduced thickness of the labial cortical wall and the presence of a horizontal groove at the philtrum area.

Japanese female Kendo practitioners are associated with high radial bone mineral density.

Osteopenia is a condition in which bone mineral density (BMD) is lower than normal. Exercise increases BMD in both the young and adults. This study aimed to compare the radial apparent BMD (aBMD) in Japanese females who are Kendo practitioners (KPs) and those with no regular exercise habits (no-REH). The analysis participants consisted of 45 KPs (mean age: 49.4 years old) and 110 no-REH (mean age: 48.8 years old). Radial aBMD was measured using an ultrasonic bone densitometry system. Radial aBMD in KPs was 196.1 ± 33.9 mg/cm3, and was 182.9 ± 45.3 mg/cm3 in no-REH participants. KPs had significantly higher BMD than no-REH participants. In KPs, left radial aBMD was 196.1 ± 33.9 mg/cm3, and right radial aBMD was 184.5 ± 37.7 mg/cm3. The left radius was also significantly higher than the right radius with respect to aBMD in KPs. After adjusting for age, body mass index, menstrual status, parous women and frequency of milk and dairy intake, the odds ratio (OR) of osteopenia associated with no-REH was 6.58 (95% confidence interval (CI): 1.72-25.1) and the prevalence ratio (PR) of osteopenia associated with no-REH was 4.12 (95% CI: 1.23-13.7). Therefore, the Kendo practice may have a protective efficacy for osteopenia in women.

Stimulation of cortical bone formation with thienopyrimidine based inhibitors of Notum Pectinacetylesterase.

A group of small molecule thienopyrimidine inhibitors of Notum Pectinacetylesterase are described. We explored both 2-((5,6-thieno[2,3-d]pyrimidin-4-yl)thio)acetic acids and 2-((6,7-thieno[3,2-d]pyrimidin-4-yl)thio)acetic acids. In both series, highly potent, orally active Notum Pectinacetylesterase inhibitors were identified.

4H-Thieno[3,2-c]chromene based inhibitors of Notum Pectinacetylesterase.

A group of small molecule thienochromenes inhibitors of Notum Pectinacetylesterase are described. We developed SAR on three series based on carbon, oxygen and sulfur replacement of the 5-position. In each series, highly potent Notum Pectinacetylesterase inhibitors were identified.

Effect of cortical bone thickness on shear stress and force in orthodontic miniscrew-bone interface - A finite element analysis.

Miniscrews are widely used in orthodontics as an anchorage device while aligning teeth. Shear stress in the miniscrew-bone interface is an important factor when the miniscrew makes contact with the bone. The objective of this study was to analyze the shear stress and force in the screw-bone interface for varying Cortical Bone Thickness (CBT) using Finite Element Analysis (FEA). Varying CBT of 1.09 mm (1.09CBT) and 2.66 mm (2.66CBT) with miniscrews of Ø1.2 mm, 10 mm length (T1), Ø1.2 mm, 6 mm length (T2) and Ø1.6 mm, 8 mm length (T3) were analyzed. Six Finite Element (FE) models were developed with cortical, cancellous bone, miniscrews and gingiva as a prism. A deflection of 0.1 mm was applied on the neck of the miniscrews at 0°, +30° and -30° angles. The shear stress and force in the screw-bone interface were assessed. The results showed that the CBT affects the shear stress and force in the screw-bone interface region in addition to the screw dimensions and deflection angulations. T1 screw generated lesser shear stress in 1.09CBTand 2.66CBTcompared to T2 and T3 screws. Higher CBT is preferred for better primary stability in shear aspect. Clinically applied forces of 200 gms to 300 gms to an anchorage device induces shear stress in the miniscrew-bone interface region might cause stress shielding. Thus, clinicians need to consider the effect of varying CBT and the size of the miniscrews for the stability, reduced stress shielding and better anchorage during orthodontic treatment.

Site selection of micro-implant anchorages in the infrazygomatic crest in adult orthodontic patients.

OBJECTIVES: To determine the optimal placement of miniscrews, this study compared adult male and female patients in terms of cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest region. METHODS: The cone beam computed tomography imaging data of 200 patients (20-30 years old; 100 males and 100 females) were collected. The right maxillary posterior teeth in the sagittal plane were divided into six levels from proximal to distal, and three measurement sites were positioned at vertical distances of 8, 10, and 12 mm from the cementum. Cortical bone density, cortical bone thickness, and available bone width were measured in 18 measurement sites in the infrazygomatic crest and analyzed statistically. RESULTS: The highest cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest in adult male and female patients were at the level of the interradicular space between the maxillary second premolar and maxillary first molar. The bone cortical density and thickness increased with vertical height, whereas the available bone width decreased with increasing vertical height. Differences were observed in cortical bone density, cortical bone thickness, and available bone width between adult male and female patients. CONCLUSIONS: The optimal implantation sites of the micro-implant anchorages in the infrazygomatic crest were at the level of the interradicular space between the maxillary second premolar and the maxillary first molar, and the vertical height of the optimal implantation site in males was appropriately higher than that in females.

Medial cortical bone thickness of the tibial diaphysis in osteoarthritis is related to lower extremity alignment and tibial morphology.

BACKGROUND: The purpose of this study was to clarify (1) the differences in cortical bone thickness (CBT) of the tibial diaphysis between healthy and osteoarthritic knees and (2) the influences of the femorotibial angle (FTA) and inclination of the medial compartment of the proximal tibia (MCT) on tibial CBT. METHODS: The study assessed 60 subjects with varus knee osteoarthritis (OA) (22 males and 38 females; mean age, 74 ± 7 years) and 53 healthy elderly subjects (28 males and 25 females; mean age, 70 ± 6 years). Three-dimensional estimated CBT of the tibial diaphysis was automatically calculated for 2752-11,296 points using high-resolution measurements from CT. The standardized CBT was assessed in 24 regions by combining six heights and four areas. Additionally, the association between the CBT, each FTA, and MCT inclination was investigated. RESULTS: The OA group showed a thicker CBT in the medial areas than in the lateral areas of the proximal tibia, while the healthy group had a thicker lateral CBT. The medial-to-lateral ratio of the proximal tibia was significantly higher in the OA group than in the healthy group. The proximal-medial CBT correlated with FTA and MCT inclinations in the OA group. CONCLUSIONS: This study demonstrated that varus osteoarthritic knees showed a different trend of proximal-medial CBT with associations in FTA and MCT inclination from healthy knees, possibly due to medial load concentration.

Male-female spatio-temporal differences of age-related bone changes show faster bone deterioration in older women at femoral regions associated with incident hip fracture.

A better understanding of how age-related bone loss affects the fracture-prone regions of the proximal femur could lead to more informed fracture-prevention strategies. Therefore, the aim of this work was to assess the spatio-temporal distribution of bone deterioration in older men and women with aging. A subset of 305 men (74.87 ± 4.76 years; mean ± SD) and 371 age-matched women (74.84 ± 4.71 years) with no history of fracture was randomly selected from the Age, Gene/Environment Susceptibility-Reykjavik study. Quantitative computed tomography (QCT) scans of the left proximal femur obtained at baseline and at 5.2 ± 0.4 years follow-up were processed to assess local changes in volumetric bone mineral density (vBMD), cortical bone thickness (Ct.Th), and internal bone structure using voxel-based morphometry (VBM), surface-based statistical parametric mapping (surf-SPM), and tensor-based morphometry (TBM). Local parametric changes within each sex and sex differences in these changes were statistically assessed using linear mixed effects models allowing for baseline and time-varying covariates, yielding Student's t-test and p-value statistical maps of the proximal femur. The statistical maps indicated regions with significant parametric changes in each sex and with significant different parametric changes between older men and older women with aging. Older women manifested significantly larger losses in vBMD, (Ct.Th), and structure than older men, and they did so in regions where deficiency in these parameters has been associated with incident hip fracture. Using longitudinal QCT scans of the proximal femur and Computational Anatomy, we provided new insights into the higher fracture rates of the proximal femur in older women compared with men of similar age providing new information on the pathophysiology of osteoporosis.

Evaluation of cortical bone thickness and root proximity at maxillary interradicular sites for mini-implant placement.

OBJECTIVES: The purpose of this study was to evaluate the interradicular cortical bone thickness, alveolar process width and root proximity for planning mini-implant placement in the maxillary alveolar process. MATERIAL AND METHODS: Eighty maxillae (right and left sides) of 40 Japanese adult skulls were examined. The samples were imaged and measured using a micro-CT system. Buccal and palatal interradicular cortical bone thickness, alveolar process width, and root proximity were measured in six interradicular sites from distal of central incisor to mesial of second molar. Buccal and palatal interradicular cortical bone thickness and alveolar process width were measured at 10 different vertical levels. Root proximity was measured at four different vertical levels. RESULTS: Buccal and palatal interradicular cortical bone thickness and alveolar process width tended to increase from crest to base of alveolar process. The buccal interradicular cortical bone thickness between canine and first premolar or between first premolar and second premolar was the greatest, and between central incisor and lateral incisor was the least. The palatal interradicular cortical bone was significantly thicker than the buccal. The root proximity between second premolar and first molar or first premolar and second premolar was the widest and between central incisor and lateral incisor it was the narrowest. CONCLUSIONS: The findings of this study suggest that recommendations when low dose 3D multislice CT or low dose cone beam imaging is not available, the results of this research may be useful in providing indicators for selecting the design of the placement site.

Influence of Proximal Humeral Cortical Bone Thickness on the Radiographic Outcome After Osteosynthesis of Proximal Humeral Fractures: Propensity Matching Score Analysis.

Introduction: Osteoporosis can affect the surgical outcomes of proximal humeral fractures in older people. Recently, the cortical bone thickness of the proximal humerus on plain radiograph has been proposed to reflect local osteoporosis of the proximal humerus; however, its effect on the surgical outcome of proximal humeral fractures remains unclear. The purpose of this study is to investigate the influence of cortical bone thickness on postoperative radiographic outcomes after osteosynthesis for proximal humeral fractures. Materials and Methods: We retrospectively identified 190 patients (≥50 years) who underwent osteosynthesis with an intramedullary nail or plate for proximal humeral fractures. The patients were categorized into 2 groups according to the cut-off value of an average proximal humerus cortical bone thickness of 6 mm on plain radiographs: patients with and without local osteoporosis. After propensity score matching, we compared the incidence of postoperative radiographic complications between the 2 groups. We also performed subgroup analyses of outcomes in a subgroup of patients who underwent intramedullary nailing and those who underwent plate fixation. Results: Propensity score matching yielded 60 patients in each group. No significant difference in complication rates was observed between the 2 groups. However, in the intramedullary nailing subgroup, the incidence of reduction loss was significantly higher in patients with local osteoporosis than in those without local osteoporosis (51.7% vs 14.3%, P = .002). Discussion: The proximal humeral cortical bone thickness had no significant effect on the overall radiographic outcome; however, reduction loss after intramedullary nailing was susceptible to local osteoporosis of the proximal humerus. Conclusion: Our study suggests that plate fixation is advantageous in preventing postoperative reduction loss in patients with lower cortical bone thickness.

Evaluation of the correlation between facial index and the cortical bone thickness of the maxilla and mandible-A computer tomography based study.

OBJECTIVES: cortical bone thickness confines the position of teeth and thus can be a limiting factor for orthodontic tooth movement. The study is aimed to correlate the cortical bone thickness of the maxilla and mandible with that of different face types, viz; dolichofacial, brachyfacial, and mesofacial. METHODS: Forty CT scans were analysed for the face types and were grouped into dolichofacial (13), brachyfacial (13) and mesofacial (14) face types. The scans were measured for the right and left side buccal and lingual cortical bone thickness at the central incisor, first and second molar regions on both the maxilla and mandible. Other parameters like basal cortical bone thickness, height, and width of cortical bone were also measured. To determine the correlation and difference between the different parameters, the obtained data was subjected to the correlation coefficient, t test, and ANOVA statistical analysis. RESULTS: Maxillary buccal cortical bone thickness of central incisors was found to be highly correlated to facial index with a correlation coefficient of - 0.833 * *. Mandibular buccal bone thickness correlated with face type and cortical bone thickness at the central incisor, first, and second molars by-0.531 * *, - 0.474 * *, and - 0.589 * *, respectively. There was a significant difference between the right and left side cortical bone thickness (p < 0.05) and also for all the parameters amongst the different face types (p < 0.05). CONCLUSION: There exists a definite correlation between the face type and the certain anatomical measurements of cortical bone morphology. Dolichofacial face types show thin buccal cortical bone, which implies the limitation of orthodontic tooth movement in these types of individuals.