Bimaxillary transverse constriction in adults: Short-term follow-up of non-surgical arch expansion.

OBJECTIVE: Concurrent maxillary and mandibular expansion is a treatment option for patients with maxillary and mandibular transverse constriction. These patients do not present with crossbite but require expansion due to narrow arches and associated crowding, dark buccal corridors and decreased anterior arch contour. The objective of the study is to first establish Bimaxillary Transverse Constriction as an under-recognized malocclusion and second to evaluate whether in adults the maxillary and mandibular arches can be successfully and safely expanded. SETTING AND SAMPLE POPULATION: Pre- and post-treatment study models and lateral cephalograms of 31 adults with Bimaxillary Transverse Constriction expanded non-surgically were analysed. Thirty adult orthodontic patients who did not require expansion served as a control. Expanders were turned no more frequently than every other day in the maxilla and every third day in the mandible. MATERIALS AND METHODS: Measurements in both arches made on OrthoCAD models were transarch widths, molar and premolar axial angulation, clinical crown height of posterior teeth and cuspids, and mandibular divergence. Retrospective comparison of the 2 groups used independent Student's t tests for mean differences between groups. RESULTS: At pre-treatment, the expansion group demonstrated significant transverse constriction compared with the control. Increased widths were achieved in the expansion group (4 mm in the maxilla and 2.5 mm in the mandible), while the control group was unchanged. The mandibular plane was unchanged. There was no buccal attachment loss. CONCLUSION: Non-surgical expansion in the maxilla and mandible is a viable treatment option for adult patients with Bimaxillary Transverse Constriction.

The implementation of the Handicapping Labio-Lingual Deviation index on access to orthodontic care.

OBJECTIVES: In 2017, the state of Illinois changed the system by which they define severe malocclusion from the DentaQuest Orthodontic Criteria Index to the Handicapping Labio-Lingual Deviation Index (HLD). The purpose of this study was to compare subjects who were submitted for coverage under either the DentaQuest Orthodontic Criteria Index or the HLD index to see if a difference exists in the number of subjects who received coverage and the type of malocclusions that were covered. METHODS: All subjects evaluated for orthodontic coverage by the Illinois Department of Human Services for treatment at the University of Illinois, College of Dentistry during the years 2016 and 2017 were included in this study. One hundred consecutively approved and 100 consecutively denied subjects from both 2016 and 2017 were selected for further analysis. RESULTS: There was a statistically significant decrease in the overall rate of approval in 2017 compared to 2016. No difference was found in the approval rate of Class I, II, or III subjects, but there was a significant decrease in the approval rate of subjects with impacted teeth. CONCLUSIONS: The implementation of the HLD index has significantly decreased access to orthodontic care for Medicaid patients in Illinois.

The effects of environment and cyclic fatigue on the mechanical properties of an indirect composite.

OBJECTIVES: The purpose of this study was to examine the flexure strength (σ) and fracture toughness (K(IC)) of three indirect dental composites (dentin, body, and incisal) with respect to loading (static and cyclic), testing environments (air and water) and ageing (0 (controls) and 6 months in air and water). METHODS: The specimens were 3 mm × 3 mm × 25 mm bars with the fracture toughness specimens having a 0.75 mm notch machined in the midspan. Static testing utilized 15 bars and cyclic testing 25 bars for each testing variable. All bars were tested using three-point loading and the cyclic testing was for 1000 cycles using a staircase approach. RESULTS: For flexure strength and fracture toughness, all specimen groups showed a decrease in mean values when exposed to cyclic loading as compared to the static loading mean and when exposed to ageing compared to the control specimens. ANOVA analysis demonstrated that dentin specimens had higher flexure strength and fracture toughness means than incisal and body specimens and that control and water specimens had higher flexure strength and fracture toughness means than aged and air specimens. CONCLUSIONS: Degradation of these materials, as a result of cyclic loading and ageing in an aqueous environment, appears to be influenced by more than just the processing of the composite.