Exploring bracket torque expression: A comparative in vitro study of new self-ligating bracket designs and archwire geometries.

OBJECTIVE: This in vitro study aimed to evaluate the torque expression efficiency when it is integrated into the bracket slot versus the bracket base. Additionally, the impact of archwire geometry (rectangular vs. rhomboid) on torque expression has been examined. MATERIAL AND METHODS: The torque expression was evaluated in a full arch printed maxillary model, focusing on tooth #11, which was positioned within an alveolus filled with Typodont wax. Three different types of brackets were utilized: conventional metallic bracket (Minidiamond™), self-ligating bracket with torque in base (Damon Q2™), and a new self-ligating bracket design with torque in slot (Damon Ultima™). Two variations of archwires were used: rectangular and rhomboid stainless steel, measuring 0.019×0.025 inches and 0.019×0.0275 inches, respectively, from ORMCO™. The study included seven groups: six experimental groups and a control group, with 15 measurements in each group, totaling 105 torque measurements. Optical impressions were taken of the tooth's original position and its final position after torque expression. STL files were superimposed using GEOMAGIC software to calculate the percentage of torque expression. RESULTS: The self-ligating bracket with torque in slot (Damon Ultima™) shows significantly higher torque expression than the self-ligating bracket with torque in base (Damon Q2™) with a rectangular stainless steel archwire (P=0.00015). The Ultima™ bracket also demonstrates higher torque expression than both the Q2™ and conventional 22° brackets with a rhomboid stainless steel archwire (P<0.003). No significant difference in torque expression was found between the rectangular and rhomboid stainless steel archwires for any bracket group (P>0.05). CONCLUSIONS: The self-ligating bracket with torque in slot shows comparable torque expression effectiveness to the conventional bracket, outperforming the self-ligating bracket with torque in base. Archwire geometry does not significantly impact torque expression.

Does malocclusion affect ingestion: a systematic review.

OBJECTIVES: The multifactorial aspect of malocclusions and their consequences on ingestion function is rarely described in the literature. The aims of this review are (i) to investigate the relationship between oral ingestion and malocclusion and (ii) to gather malocclusion tools that could help screen subjects at risk of malocclusion-related ingestion disorders. MATERIAL AND METHODS: A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P 2015) guidelines. The analysis methods and inclusion criteria have been documented in a protocol published in the Prospective International Register of Systematic Reviews (PROSPERO) under the registration number CRD42023395840. The bibliographic search involved the PubMed®, Cochrane and PROSPERO databases. RESULTS: A total of 29 articles published between 2007 and 2023 were retained by the search criteria for the qualitative synthesis. Twenty of the studies found that the severity of malocclusion has a negative impact on oral ingestion. This review highlights that malocclusion and ingestion impairments are associated but it is not possible to determine causality due to the observational approach of many of the studies. CONCLUSION: Malocclusion has a negative impact on ingestion function. During orthodontic consultations, particular interest should be directed towards chewing, biting, and swallowing disorders, which can affect patients' nutritional status. This review offers arguments for designing further studies assessing the extent to which malocclusions may affect nutritional status. CLINICAL RELEVANCE: Orthodontic treatment should focus on improving patients' ingestion.

Only severe malocclusion correlates with mastication deficiency.

OBJECTIVES: The relation between level of dentofacial deformity and extent of masticatory deficiency was studied. DESIGN: Three groups of human young adults were formed: (i) subjects needing orthodontics plus orthognathic surgery (SevDFD, n=18), (ii) subjects needing orthodontic treatment only (ModDFD, n=12), and (iii) subjects needing no treatment (NoDFD, n=12). For mastication tests, carrot boluses were collected at the deglutition time. Bolus particle size range was expressed as d50 value, which was compared with the Masticatory Normative Indicator (MNI). Index of treatment need (IOTN), global oral health assessment index (GOHAI) and chewing kinematic characteristics were also recorded. We used a general linear model univariate procedure followed by a Student-Newman-Keuls test. RESULTS: All the SevDFD subjects showed impaired mastication with MNI above the normal limit (d50 mean=7.23mm). All the ModDFD subjects but one were below this limit (d50 mean=2.54mm), and so could adapt to a low level of masticatory impairment as also indicated by kinematics. IOTN indicated a treatment need for ModDFD (3.7±0.5) and SevDFD (4.3±0.6) groups, while GOHAI values were unsatisfactory only for SevDFD (42.6±9.2 vs. 55.3±1.9). CONCLUSIONS: Our findings emphasize the need for an objective evaluation of masticatory function to discern truly deficient mastication from mild impairment allowing satisfactory adaptation of the function. However, malocclusions are known to worsen with time justifying thus their corrections as early as possible.

Validation of the child oral health impact profile (COHIP) french questionnaire among 12 years-old children in New Caledonia.

BACKGROUND: The Child Oral Health Impact Profile (COHIP) is an Oral Health Related Quality of Life (OHRQOL) tool that assesses the impact of oral diseases on quality of life in children. This study aimed to assess the validity of the COHIP French questionnaire (45 items) and to evaluate the OHRQOL of 12-years children in New Caledonia. METHODS: After cultural adaptation of the COHIP questionnaire, data were collected from clinical oral examinations and self-administered questionnaires in a representative sample of children aged 12 years in New Caledonia. Questions related to socio-demographic status or children's perception of their oral and general health were added to the COHIP questionnaire. Studying the association between COHIP scores and health subjective perceptions or dental status indicators assessed concurrent and discriminant validity. The items of the COHIP were subjected to principal components analysis. Finally, reproducibility and reliability were evaluated using Intraclass Correlation Coefficients (ICC) and Cronbach's alpha coefficient. RESULTS: Two hundred and thirty-six children participated in the main study; mean age was 12.6 ± 0.31 years, 55.1 % were girls and diverse ethnic groups were represented. A preliminary reliability analysis has led to calculate COHIP scores with 34 items as in the English version, scores ranged from 35 to 131 (mean ± SD, 101.9 ± 16.84). Lower COHIP scores were significantly associated with the self-perception of poor general or oral health. COHIP was able to discriminate between participants according to gender, ethnic group, oral hygiene, dental attendance, dental fear and the presence of oral diseases. Test-retest reliability and scale reliability were excellent (ICC = 0.904; Cronbach's alpha coefficient = 0.880). Four components were identified from the factor analysis. CONCLUSION: The French 34-items COHIP showed excellent psychometric properties. Further testing will examine the structure and utility of the instrument in both clinical and epidemiological samples.

[Reciprocal relationships between orthodontics and periodontics: relevance of a synergistic action]. / Rapports réciproques entre orthodontie et parodontologie. Intérêt d'une synergie d'action effective.

The aim of this article is to review evidence on the reciprocal relationships between orthodontics and periodontics. Normal intra-arch and inter-arch relationships have long been considered as an anatomic prerequisite for the preservation of dental health and function. Certain malocclusion traits are associated with difficulties in maintaining good oral hygiene and as a consequence to poor periodontal condition. Therefore, proper alignment of the teeth provided by orthodontic treatment may promote good control of soft deposit and calculus and subsequent periodontal inflammation. The tendency of orthodontic appliances, particularly the brackets and bands to promote the accumulation of plaque and thus increasing the risk of developing localized periodontal disease must however be constantly emphasized. Periodontitis involves progressive loss of the alveolar bone around the teeth, pathological tooth migration and gingival recession with pathological tooth migration and gingival recession as a possible outcome. The effectiveness of orthodontics in conjunction with periodontics in the management of these esthetic and functional defects is highlighted in this review.