Relationships among maxillofacial morphologies, bone properties, and bone metabolic markers in patients with jaw deformities

Association between bilateral condylar resorption and reduced volumes of the craniofacial skeleton and masticatory muscles in adult patients: A retrospective study

Objectives

This retrospective cohort study aimed to analyze volumes of craniomaxillofacial bone and masticatory muscles of young adults with bilateral idiopathic condylar resorption.

Methods

This was a retrospective cohort study of 84 adults with bilateral idiopathic condylar resorption (BCR) and 48 adults with normal temporal-mandibular joint (TMJ) matched for age and sex (mean age, 23.2 ± 3.6 years). The volumes of craniomaxillofacial bone and masticatory muscles, as well as intercondylar angle were measured. Unpaired t-tests and Pearson correlation tests were applied to analyze the data. Multivariable linear regression models were used to estimate the association between bilateral condylar volume and volumes of craniomaxillofacial bone and masticatory muscles adjusted for age, sex, and disc status.

Results

Compared to the control group, the BCR group displayed significant decreased volumes of craniomaxillofacial bone (p < 0.001), craniomaxillofacial bone without mandible (p < 0.001), mandible (p < 0.001), mandible without mandibular condylar process (p < 0.001), bilateral masseter muscle (p < 0.001) and bilateral temporalis muscle (p < 0.001), as well as the intercondylar angle (p < 0.001). These variables were significantly correlated to the volume of mandibular condylar process (0.5< r < 0.8; p < 0.001). By linear regression analyses, significant associations were found for the bilateral condylar volume with craniomaxillofacial bone volume and mandible bone volume.

Conclusions

Young adults with BCR displayed smaller volumes of craniomaxillofacial skeleton and masticatory muscles, and smaller intercondylar angle than the normal patients. The craniofacial musculoskeletal volume and intercondylar angle are associated with mandibular condylar process volume.

Fracture risk prediction in old Chinese people-a narrative review

With aging, the burden of osteoporotic fracture (OF) increases substantially, while China is expected to carry the greatest part in the future. The risk of fracture varies greatly across racial groups and geographic regions, and systematically organized evidence on the potential predictors for fracture risk is needed for Chinese. This review briefly introduces the epidemiology of OF and expands on the predictors and predictive tools for the risk of OF, as well as the challenges for their potential translation in the old Chinese population. There are regional differences of fracture incidence among China. The fracture incidences in Hong Kong and Taiwan have decreased in recent years, while it is still increasing in mainland China. Although the application of dual-energy X-ray absorptiometry (DXA) is limited among old Chinese in the mainland, bone mineral density (BMD) by DXA has a predictive value similar to that worldwide. Other non-DXA modalities, especially heel QUS, are helpful in assessing bone health. The fracture risk assessment tool (FRAX) has a good discrimination ability for OFs, especially the FRAX with BMD. And some clinical factors have added value to FRAX, which has been verified in old Chinese. In addition, although the application of the osteoporosis self-assessment tool for Asians (OSTA) in Chinese needs further validation, it may help identify high-risk populations in areas with limited resources. Moreover, the translation use of the muscle quality and genetic or serum biomarkers in fracture prediction needs further works. More applicable and targeted fracture risk predictors and tools are still needed for the old Chinese population.

Relationship between condylar surface CT value in coronal plane and condylar morphology in jaw deformity patients

OBJECTIVES

This study aimed to examine the relationship between condylar surface computed tomography (CT) values in the coronal plane and condylar morphology in patients with jaw deformities classes II and III before and after orthognathic surgery.

MATERIALS AND METHODS

The maximum CT values (pixel values) at three points on the condylar surface, height, and joint space were measured on the coronal plane. The condylar width, thickness, and angle were measured on the horizontal plane preoperatively and at 1 year postoperatively.

RESULTS

A total of 112 temporomandibular joints of 56 female patients were divided into two groups according to skeletal class (56 joints each in class II and class III). The maximum CT values of class II were higher than those of class III at the medial, central, and lateral sites on the condylar surface, preoperatively and at 1 year postoperatively (P < 0.05). CT values of the condylar surface were significantly negatively correlated with the condylar heights at the center and lateral sites preoperatively and at 1 year postoperatively (P < 0.05).

CONCLUSIONS

Condylar surface CT values in the coronal plane are associated with condylar morphology, including condylar height.

Bone mineral density and muscle mass in adults with developmental skeletal discrepancies

Background

It was aimed to investigate the musculoskeletal status in individuals diagnosed with skeletal discrepancies.

Methods

This case–control study was performed on 35 patients with developmental skeletal discrepancies listed for orthognathic surgery as a case group and 33 patients who were nominated for wisdom tooth removal as a control group. All participants were aged 18–40 years and the research was carried out in the period between May 2018 and May 2019. Dual X-ray absorptiometry (DEXA) was used to assess bone mass density at three bone sites: total hip, femoral neck, and the spinal lumbar vertebrae (L1-L4). The appendicular muscle mass index (ASMI) was measured based on the four limbs from the DEXA scan.

Results

Our data showed that 45.7% (16) of the case group were osteopenic or osteoporotic while in the control group only 21.2% (7) were osteopenic in at least one region (total hip, femoral neck, or lumbar) (p-value = 0.03).

Regarding muscle mass, there was significantly lower SMI in subjects with skeletal discrepancies (case group) compared with the control group (median (IQR) 5.9 (2.5) vs. 6.8 (2.9) (kg/m2), respectively, p = 0.04).

Conclusions

There is an essential need for more studies to understand the exact interrelationship between musculoskeletal status and skeletal jaw discrepancies.

The relationship between the size of temporomandibular joint condyle and the sagittal disc-condyle position in adults

OBJECTIVE

To explore the relationship between the size of temporomandibular joint (TMJ) condyle and the sagittal disc-condyle position and the relationship between the condylar size and craniofacial structure.

METHODS

Seventy-four subjects (23.82 ± 3.77 years) underwent cone beam computed tomography (CBCT) and lateral cephalograms for orthodontics and volunteered to undergo magnetic resonance imaging (MRI). Mimics was used to calculate the volume and surface area of the condyle. MRI was used to evaluate the sagittal disc-condyle position. The lateral cephalograms were analyzed by Jarabak analysis.

RESULTS

The condylar volume and surface area were negatively correlated with the sagittal disc-condyle position. The condylar volume and surface area were positively correlated with Ar-Go, S-Go, and S-Go/N-Me*100% (p < 0.05) and negatively correlated with ∠Ar-Go-Me and ∠N-Go-Me (p < 0.05).

CONCLUSION

Condylar size was negatively correlated with the sagittal disc-condyle position. The condylar size was correlated with the vertical skeletal pattern.

Evaluation of condylar surface CT values related to condylar height reduction after orthognathic surgery

This study was performed to evaluate the relationship between condylar height reduction and changes in condylar surface computed tomography (CT) values in jaw deformity patients following orthognathic surgery. Mandibular advancement by sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy was performed in class II patients, and mandibular setback by SSRO with Le Fort I osteotomy was performed in class III patients. The maximum CT values (pixel values) at five points on the condylar surface and the condylar height, ramus height, condylar square, ramus angle, and gonial angle in the sagittal plane were measured preoperatively and 1 year postoperatively. Disc position was classified as anterior disc displacement (ADD) or other types by using magnetic resonance imaging (MRI). Ninety-two condyles of 46 female patients were prepared for this study. Their temporomandibular joints (TMJs) were divided into two groups based on class (46 joints in class II and 46 joints in class III) and two groups based on the findings (25 joints with ADD and 67 joints with other findings). ADD with and without reduction was observed in two joints in the class III group and in 23 joints in the class II group. The distribution of ADD incidence had not changed 1 year after surgery. Condylar height decreased 1 year after surgery in both class II patients (mandibular advancement) (p < 0.0001) and class III patients (mandibular setback) (p = 0.0306). Similarly, condylar height decreased 1 year after surgery both in patients who showed ADD (p = 0.0087) and those with other types (p = 0.0023). Significant postoperative increases at all angle sites on the condylar surface were found in the class II (p < 0.05) and ADD (p < 0.05) groups. This study showed that an enhanced condylar surface CT value might be one sign of condylar height reduction related to sequential condylar resorption, in combination with ADD.

Low skeletal bone mineral density as a potential aetiological factor towards idiopathic condylar resorption

The aim of this study was to investigate the contributing factor of impaired skeletal quality in the pathogenesis of idiopathic condylar resorption (ICR). One hundred and twenty-six patients with MRI-confirmed ICR and 596 patients with disc displacement (DD) without a diminished condyle, of both sexes, were included. Dental examinations and retrospective surveys regarding temporomandibular joint symptoms and progression of maxillofacial deformities were conducted. Skeletal bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and converted to T-scores and Z-scores. Results showed that ICR patients had a smaller overbite (1.56±3.3 vs 3.05±2.0mm), larger overjet (4.9±2.4 vs 3.5±1.9mm), larger range of mouth opening (36.5±6.7 vs 33.6±7.1mm), and higher rates of anterior open bite and mandibular retrusion compared to DD patients (all P<0.001). ICR was associated with an increased probability of low skeletal BMD at chronological age in females (P=0.020) but not in males (P=0.095). This study indicates that reduced BMD may predispose females to an exacerbated condylar resorption process in addition to increased joint loading initiated from DD.

Characteristics of bone biochemical indices in predicting secondary osteoporotic fracture after intertrochanteric fracture in elderly women

BACKGROUND

This study aimed to explore the characteristics of bone biochemical indices, including bone mineral density (BMD), metabolic markers in elderly women with osteoporotic intertrochanteric fracture and their relevance in secondary fracture.

METHODS

The standard for follow-up from 58 elderly women was established to analyse the BMD in the injured hip, healthy hip, and the vertebra at 1 week and 12 months after fracture. The serum levels of total procollagen type N-terminal propeptide (tPINP) and the age-related type I cross linked C-telopeptide (β-CTX) were recorded and compared between those patients with and without secondary fractures within 12 months.

RESULTS

Twelve months after fracture, the serum levels of tPINP and β-CTX were significantly higher than the baseline values (p < 0.01). The tPINP baseline in patients with secondary fracture was significantly lower than that in the rest patients without secondary fracture (p < 0.01). The β-CTX baseline was notably higher than that without secondary fracture (p < 0.01). BMD values of the three periods had no significantly difference.

CONCLUSION

The serum levels of tPINP and β-CTX are of great value in earlier and more sensitively reflecting the condition of bone turnover in body. Meanwhile, they can predict the subsequent fracture risk more accurately combined with a lower BMD.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Besides BMD, bone microstructure and remodeling levels can be accurately measured by bone biochemical indices. The main objective of this research is to explore the change of BMD and the serum level of bone biochemical indices of elderly women who suffered unilateral intertrochanteric fracture within 12 months. Simultaneously, with aim to better obtain bone remodeling level and predict more accurately the risk of a secondary osteoporotic fracture, bone biochemical indices of these patients, who undergo secondary osteoporotic fracture or not, are collected during follow-up and compared respectively.