Three-Dimensional Changes of Condylar Position After Bimaxillary Surgery to Correct Skeletal III Malocclusion: Cone Beam Computed Tomography Voxel-Based Superimposition Analysis.

BACKGROUND: The stability of the condylar position within the first 3 months after orthognathic surgery in patients with skeletal Class III malocclusion is crucial for subsequent orthodontic treatment. PURPOSE: The purpose was to compare condylar positional changes 3 months after bimaxillary surgery to correct skeletal Class III deformities, utilizing the conventional two-dimensional combined with cone beam computed tomography voxel-based superimposition analysis. STUDY DESIGN, SETTING, SAMPLE: This retrospective cohort study included skeletal Class III patients undergoing bimaxillary orthognathic surgery at Khon Kaen University, Thailand, in 2020. Exclusion criteria were patients with temporomandibular disorder symptoms, facial asymmetry prior to the surgery, or surgical complications. EXPOSURE VARIABLE: The exposure variable was the timing, both preoperatively and 3 months postoperatively. This 3-month postoperative time point was chosen because complete healing of the bimaxillary surgery is expected by then, without any potential influence of condylar changes resulting from subsequent orthodontic treatment. MAIN OUTCOME VARIABLES: The outcome variables are condylar position measurement, joint space (mm), and axial condylar angle (degrees). COVARIATES: Demographics (age, sex) and surgical details (direction and amount of movement) were collected as covariates. ANALYSES: Statistical analysis of condylar positional changes and correlations was performed using paired t-test and linear correlation (P value < .05), respectively. RESULTS: The sample included 11 subjects (22 condyles), with a mean age of 24 ± 5.24 years. Both two-dimensional measurements and voxel-based three-dimensional superimposition showed significant changes in condylar position 3 months after bimaxillary surgery: inferior (0.45 ± 0.26 mm, P < .001), posterior (0.46 ± 0.39 mm, P = .003), lateral (0.38 ± 0.42 mm, P = .01) displacement, and inward rotation (5.21 ± 2.54°, P < .001). No significant correlation was found between jaw movement distance and condylar changes. CONCLUSION AND RELEVANCE: To our knowledge, this is the first study to report measures of condylar changes at 3 months, when complete healing of the osteotomies would be expected, using Le Fort I osteotomy for maxillary advancement combined with bilateral sagittal split ramus osteotomy for mandibular setback. These changes are small in magnitude and may be of little relevance to patient care.

Prevalence and risk indicators of early childhood caries among toddlers in Caloocan City, Philippines: a cross-sectional study.

BACKGROUND: Limited published data exist on early childhood caries (ECC) among children 2 years old and below. The study aimed to determine ECC prevalence and its association with socio-demographic indicators, feeding practices and oral health behaviours among children aged 2 years and below in the Philippines. METHODS: A cross-sectional study observed young children aged 4-24 months in primary health centers. Each child's caregiver was interviewed and dental examinations were done on every child by one calibrated dentist using the ICDAS. Poisson regression using robust variance estimator analysis identified significant variables associated with ECC. RESULTS: Seven hundred three healthy children were observed at a mean age of 13.3 ± 2.4 months. ECC prevalence was 29.2% (95% confidence interval: 26.0-32.7) among toddlers who showed a mean number of 6.7 ± 3.1 erupted teeth. Multiple regression revealed that child's age (prevalence ratio, PR = 1.07), caregiver's educational level (PR = 1.43), continued breastfeeding (PR = 1.36), frequent eating (PR = 1.24), visible plaque observed by the caregiver (PR = 1.34) and in the oral examination (PR = 2.90) were significant to ECC prevalence. CONCLUSIONS: ECC is alarmingly prevalent in toddlers, marked by early onset and untreated decay. Prioritizing preventive measures in the first two years of life is crucial for understanding dietary impacts and promoting oral hygiene.

Expression of human caspase-4 in the gingival epithelium affected with periodontitis: Its involvement in Porphyromonas gingivalis-challenged gingival epithelial cells.

OBJECTIVE: Implication of human caspase-4 in periodontitis and in sensing periodontal pathogens by gingival epithelial cells (GECs) is unclear. This study aimed to determine caspase-4 and interleukin (IL)-18 expressions in gingival tissues affected with periodontitis and to investigate caspase-4 involvement in mediating innate immune responses in GECs. DESIGN: Ex vivo, caspase-4 and IL-18 expressions in gingival biopsies, obtained from healthy participants with periodontitis or clinically healthy gingiva (N = 20 each), were determined by immunohistochemistry. In vitro, caspase-4 activation in cultured GECs stimulated with Porphyromonas gingivalis or Fusobacterium nucleatum was analyzed by immunoblotting. mRNA expressions of human ß-defensin-2 (hBD-2), IL-8, and IL-18 in stimulated GECs in the presence or absence of a caspase-4 inhibitor were assayed by RT-qPCR. RESULTS: Ex vivo, compared with healthy gingival epithelium, the epithelium affected with periodontitis displayed a significant decrease in caspase-4 expression (P = 0.015), whereas IL-18 expression was significantly increased (P = 0.012). Moreover, the expression of caspase-4, but not IL-18, was found to be a predictor of periodontitis (P = 0.007). In vitro, caspase-4 was activated in cultured GECs challenged with P. gingivalis, but not F. nucleatum. mRNA upregulations of hBD-2, IL-8, and IL-18 upon P. gingivalis stimulation were significantly reduced when caspase-4 was inhibited (P < 0.05), whereas the inhibitor failed to suppress those inductions by F. nucleatum. CONCLUSIONS: Caspase-4 expression is diminished in the epithelium affected with periodontitis while that of IL-18 is enhanced. Caspase-4 activation in P. gingivalis-infected GECs upregulates the three innate immune effector molecules, suggesting a possible sensing mechanism of caspase-4 in GECs in periodontal disease pathogenesis.

Effect of biting speed and jaw separation on force used to incise food.

Biting food too quickly might affect the control of jaw-closing muscles and the estimation of bite force. The objectives of this study were to compare the incisal bite forces used to cut food and the activity of masseter (MA) and anterior temporalis (AT) muscles between slow, habitual and fast biting speeds and also between small and large jaw openings. Twenty subjects were asked to use their incisors to cut through a 5 mm thick of chewing gum. In the first experiment, subjects bit at 10-mm incisal separation with slow, habitual and fast biting speeds, and in the second experiment, subjects bit with their habitual speed at 10- and 30-mm incisal separations. The activities in the MA and AT muscles were assessed with surface electromyography, and the bite force was recorded by a force sensor placed beneath the chewing gum. Peak bite forces and associated MA amplitudes were increased significantly as biting speed was increased (P's < .05). Anterior temporalis amplitude was significantly increased during fast biting compared to slow and habitual biting (P's < .001). At 30-mm incisal separation, both peak bite force and AT amplitude were significantly increased, whereas MA amplitude was significantly decreased, compared to those at 10-mm separation (P's < .05). Biting off food quickly with incisor teeth results in larger activities in both MA and AT muscles. In addition, biting a large piece of food resulted in increased activity of AT muscle. Both conditions could be injury stimulator for jaw muscles.