Hemimandibular Elongation: Is the Corrected Occlusion Maintained Long-Term? Does the Mandible Continue to Grow?

Classification and characterization of facial asymmetry in adult patients with skeletal Class III malocclusion using cluster analysis

INTRODUCTION

This study aimed to analyze the comprehensive maxillofacial features of patients with skeletal Class III malocclusion and facial asymmetry to develop a classification system for diagnosis and surgical planning.

METHODS

A total of 161 adult patients were included, with 121 patients in the asymmetry group (menton deviation >2 mm) and 40 patients in the symmetry group (menton deviation ≤2 mm). Twenty-eight variables were determined, including transverse translation, roll and yaw of each facial unit, transverse width, mandibular morphology, and transverse dental compensation. Principal component (PC) analysis was conducted to extract PCs, and cluster analysis was performed using these components to classify the asymmetry group. A decision tree was constructed on the basis of the clustering results.

RESULTS

Six PCs were extracted, explaining 80.622% of the data variability. The asymmetry group was classified into 4 subgroups: (1) atypical type (15.7%) showed an opposite roll direction of maxillary dentition than of menton deviation; (2) compound type (34.71%) demonstrated significant ramus height differences, maxillary roll, and mandibular roll and yaw; (3) mandibular yaw type (44.63%) showed slight mandibular yaw without mandibular morphology asymmetry; and (4) maxillary-shift type (4.96%) shared similarities with the compound type but showed significant maxillary translation. The classification and regression tree model achieved a prediction accuracy of up to 85.11%.

CONCLUSIONS

This study identified 4 distinct phenotypes using cluster analysis and proposed tailored treatment recommendations on the basis of their specific characteristics. The classification results emphasized the importance of spatial displacement features, especially mandibular yaw, in diagnosing facial asymmetry. The established classification and regression tree model enables clinicians to identify patients conveniently.

Accuracy of skeletal scintigraphy for the evaluation of mandibular growth disorders: a systematic review

Bone scans, reflecting blood flow and metabolic activity in a region of interest, are frequently used to evaluate mandibular growth disorders. Increased uptake is a non-specific finding and can occur as a result of multiple causes. The correlation between radioactive tracer uptake and growth activity has not been consistently demonstrated. The aim of this study was to assess the accuracy of planar skeletal scintigraphy (SS), single-photon emission computed tomography (SPECT), and SPECT with computed tomography (CT) images (SPECT/CT) in detecting abnormal mandibular growth activity compared to clinical and radiographic/tomographic methods (reference standard) and histologic findings. A systematic review was conducted following the PRISMA guidelines. Sensitivity, specificity, and accuracy were calculated for planar SS, SPECT, and SPECT/CT. Compared to the reference standard, SPECT/CT had the best diagnostic accuracy (76.5% sensitivity, 90.4% specificity, 83.2% accuracy), followed by planar SS (81.8% sensitivity, 84.5% specificity, 83.0% accuracy) and SPECT (77.7% sensitivity, 72.4% specificity, 74.5% accuracy). The results of this study indicate that SPECT/CT has the best clinical correlation, but the certainty of the evidence is low. The differences in sensitivity and specificity between the three index tests were not clinically significant. The three tests can be useful, with only a small difference in their diagnostic value. Histopathology was found not to be satisfactory as a reference standard.

A conceptual framework for treating jaw deformities in patients with abnormal condyles: preservation versus replacement of the glenoid fossa-disc-condyle-ramus

This article outlines a conceptual approach to the reconstruction of jaw deformities associated with abnormalities in the mandibular condyle. The authors describe a hierarchy of reconstruction, emphasizing use of the least invasive and progressing to the most complex and invasive techniques, depending on the nature and severity of the underlying deformity, prior operations, patient age, and stage of growth. Consider joint preservation orthognathic surgical correction, followed by biological techniques for replacement of the condyle, and avoid replacing a functional temporomandibular joint based only on radiographic remodeling and concerns about potential future flare-ups of disease based on anecdotal data.

Common Patterns of Developmental Dentofacial Deformities: A Biologic Classification System

Jaw disharmonies that are recognized after birth and that present in association with the pre-pubertal growth spurt are called developmental dentofacial deformities. These deformities occur during the normal growth phase of the face with degrees of either excess or deficiency in one or more vectors of the jaws. Clinical observation combined with radiographic analysis confirms that developmental dentofacial deformities tend to occur in 6 distinct and repetitive biologic patterns. Once the individual’s jaw growth pattern is known, the natural progression of their deformity, the functional consequences on speech articulation, chewing ability, swallowing mechanism, and breathing, and the locations of skeletal dysmorphology that require surgical intervention fall into place. The purpose of the manuscript is to review the 6 common patterns.