Individual, familial and country-level factors associated with oral hygiene practices in children: an international survey.

BACKGROUND: Maintaining good oral hygiene is key to preventing dental caries and periodontal disease. Children and adolescents with good oral hygiene behaviours are likely to grow into adults with the same behaviours. This study assessed the frequency of using various oral hygiene methods among children and adolescents from different countries and individual, familial and country-level factors associated with the use of these methods. METHODS: A multi-country online survey collected data from caregivers of children in 2020-21 about children's use of oral hygiene methods including toothbrush, fluoridated toothpaste, mouthwash, dental floss and miswak using self-administered, close-ended questions. Adjusted multilevel logistic regression models were used to assess the relationship between each of the five oral hygiene methods (dependent variables) and the independent factors: sex, age, and history of dental visits (individual factors), mother's education and area of residence (familial factors) as well as country income and region (country-level factors). RESULTS: A total of 4766 parents/caregivers were included from 20 countries (77.4% Eastern Mediterranean-region and 41.6% lower middle income countries). The most frequent oral hygiene methods were using toothbrush and toothpaste (90% and 60.3%). The use of oral hygiene methods differed by age, sex and history of dental visits as well as mother's education and area of residence (P < 0.05). In addition, children from low income countries had significantly lower odds of using mouthwashes and dental floss than those from high income countries (AOR = 0.55, 95% CI 0.31, 0.98 and AOR = 0.34, 95% CI 0.12, 0.97) whereas children from the European region had higher odds of using mouthwash (AOR = 2.82, 95% CI 1.27, 6.26) and those from the region of the Americas had higher odds of using dental floss (AOR = 3.84, 95% CI 1.28, 11.52) than those from the Eastern Mediterranean region. CONCLUSIONS: The use of various oral hygiene methods is associated with individual, familial and country-level factors. Oral health promotion programs should be developed taking into account these influences.

Effect of total occlusal convergence on fit and fracture resistance of zirconia-reinforced lithium silicate crowns.

INTRODUCTION: Computer-aided design (CAD) and computer-aided manufacturing (CAM) monolithic crowns are gaining momentum. Limited evidence exists about the effect of tooth preparation total occlusal convergence (TOC) on marginal and internal gap distances in addition to load to fracture values. AIM: The aim of this study was to evaluate, by microcomputed tomography (µCT), the influence of 12° and 20° TOC on marginal and internal adaptation of zirconia-reinforced lithium silicate (ZLS) crowns. Moreover, values of load to fracture with and without initial cyclic loading (CL) were compared. MATERIAL AND METHODS: Forty ZLS crowns were fabricated on dies with TOC of 12° and 20°, 20 crowns for each group. µCT was used to compare marginal and internal adaptation. Each specimen was measured at 140 points distributed on all tooth preparation surfaces for 2D gap distance assessment. 3D gap volume was also evaluated. Crowns were then cemented and divided into two subgroups; the first was stored in distilled water (no cyclic loading [NCL] subgroup), the second was subjected to CL (CL subgroup). RESULTS: Factorial repeated measures ANOVA followed by Bonferroni post hoc in addition to independent and dependent t-tests were used for statistical analysis. Marginal gap, absolute marginal discrepancy, and occlusal gap measurements showed significant differences between the measurement sites. Static load to fracture values showed significant differences between TOC groups for both NCL (P=0.011) and CL (P=0.025) subgroups. CONCLUSION: An increase of TOC from 12° to 20° did not affect marginal and internal adaptation but resulted in higher values of load to fracture of ZLS crowns. CL simulating 1 year of service did not result in fatigue failure.

Influence of denture adhesives on occlusion and disocclusion times.

STATEMENT OF PROBLEM: The effectiveness of adhesives in enhancing several functional aspects of complete denture performance has been well established. The direct influence of adhesives on occlusal contact simultaneity has not yet been investigated. PURPOSE: The purpose of this crossover clinical trial was to evaluate quantitatively the influence of adhesives on occlusal balance by recording timed occlusal contacts; namely occlusion time (OT) and disocclusion time during right (DT-right) and left (DT-left) excursions by using computerized occlusal analysis. MATERIAL AND METHODS: A crossover clinical trial was adopted. Assessments were carried out while participants (n=49) wore their dentures first without then with adhesives. Computerized occlusal analysis using the T-Scan III system was conducted to perform baseline computer-guided occlusal adjustment for conventionally fabricated dentures. Retention and stability assessment using the modified Kapur index and recording of OT and DT-right and DT-left values using the T-Scan III were subsequently carried out for all dentures, first without adhesives and then after application of adhesive. All T-Scan procedures were carried out by the same clinician. Wilcoxon signed-rank test was used to analyze the Kapur index scores and occlusal parameters (α=.05). RESULTS: Stability and retention of conventional dentures ranged initially from good to very good. However, adhesive application resulted in significant improvement (P<.001) in stability and retention and a significant decrease in duration of all occlusal parameters (OT [P=.003], DT-right [P=.003], and DT-left [P=.008]). CONCLUSIONS: Adhesives significantly decreased OT and DT durations in initially well-fitting complete dentures with fairly well balanced occlusion, and further enhanced denture stability and occlusal contact simultaneity.

Surface roughness and internal porosity of partial removable dental prosthesis frameworks fabricated from conventional wax and light-polymerized patterns: a comparative study.

STATEMENT OF PROBLEM: Surface roughness and internal porosity are 2 potential risk factors that threaten the biocompatibility and long-term mechanical stability of cast partial removable dental prostheses frameworks. PURPOSE: The purpose of this study was to investigate the influence of the material, of conventional wax patterns, and the recently introduced light-polymerized patterns on the initial surface roughness and internal porosity of the cobalt-chromium castings of partial removable dental prostheses. MATERIAL AND METHODS: Twenty-eight identical partial removable dental prosthesis frameworks were fabricated on a cast of a maxillary Kennedy Class III modification 1 partially edentulous patient. Fourteen frameworks were fabricated from each pattern material. The initial surface roughness, Ra (µm), of the resultant castings was measured with a profilometer. Radiographs of the castings were made on dental occlusal films with a dental x-ray unit with the following exposure conditions: tube voltage 70 kV; exposure time 1.0 seconds; tube current 7 mA; and source-film distance 35 cm. The number and size of porosities in the 3 main components (clasp units, major connectors, denture base meshwork) were assessed. Statistical analysis was conducted with the independent sample t test for surface roughness and the Mann Whitney test for internal porosity (α=.05). RESULTS: The statistical analysis of mean surface roughness and internal porosity revealed no significant difference between the 2 groups. CONCLUSIONS: The surface roughness and internal porosity of frameworks fabricated from conventional wax and Liwa patterns were comparable, with no significant differences between the 2 pattern materials.