Influence of malocclusion on oral health-related quality of life in children: a seven-year cohort study

ABSTRACT Objective: To assess the influence of early childhood malocclusion on oral health-related quality of life (OHRQoL). Methods: 7-year cohort study involving 639 preschoolers (1 to 5 years) who had been evaluated initially with a survey conduced in 2010. Children completed the Brazilian version of the Child Perception Questionnaire (CPQ8-10) to assess OHRQoL during the follow-up period. Exploratory variables were collected at baseline, including the presence and severity of malocclusion (overjet and lip coverage). Socioeconomic characteristics, oral health behavior, and patterns of dental attendance were also investigated. A multilevel Poisson regression model was used to fit the association between malocclusion and OHRQoL. With this approach, incidence rate ratio (IRR) and 95% confidence intervals (95% CI) were calculated. Results: A total of 449 children were re-evaluated (follow-up rate, 70.3%). The prevalence of accentuated overjet and inadequate lip coverage was 13.5% and 11.9%, respectively. The mean (±SD) CPQ8-10 score was 10.57±10.32. The presence of inadequate lip coverage was associated with higher overall mean CPQ8-10 scores (IRR 1.51; 95% CI 1.29-1.77), and social well-being, emotional well-being, and functional limitation domains. Children with accentuated overjet (>3mm) also demonstrated higher overall scores on the CPQ8-10 than their normal counterparts. The presence of this condition also influenced the oral symptom (IRR 1.29; 95% CI 1.08-1.53) and emotional well-being (IRR 1.30; 95% CI 1.02-1.66) domains. Conclusion: Results of the present study suggest that early childhood malocclusion is a risk factor for low OHRQoL in future.

Do dental bleaching sessions prior to orthodontic treatment change the bond strength of esthetic brackets?

ABSTRACT Objective: The aim of this experimental in vitro study was to evaluate whether dental bleaching performed before orthodontic treatment change the shear bond strength (SBS) of monocrystalline and polycrystalline esthetic brackets. Methods: Sixty (60) bovine incisors teeth were used and randomly divided into the following six groups (n=10): SCP (without bleaching/polycrystalline brackets); SCM (without bleaching/monocrystalline brackets); 1CP (one bleaching session/polycrystalline brackets); 1CM (one bleaching session/monocrystalline brackets); 3CP (three bleaching sessions/polycrystalline brackets); and 3CM (three bleaching sessions/monocrystalline brackets). The brackets were bonded seven days after the bleaching sessions. The samples were submitted to the SBS test in a universal testing machine (Instron model 4411) at 1 mm/min crosshead speed. The two-way analysis of variance (ANOVA) and the Tukey tests were performed at a 5% level of significance. After the mechanical test, samples were evaluated to determine the adhesive remnant index (ARI). Results: The SBS values were significantly higher for the monocrystalline brackets, when compared with the polycrystalline type (p< 0.0001), and significantly higher with three bleaching sessions than without bleaching (p< 0.0436). The ARI showed predominance of failures between the bracket and resin for all the groups (score 3). Conclusion: Three dental bleaching sessions increased the SBS values. Monocrystalline brackets showed higher SBS values than the polycrystalline type.

Supernumerary teeth in patients with cleft lip and palate: the tooth germs do not separate

ABSTRACT Introduction: Supernumerary teeth in cases of cleft lip and palate do not result from the division of normal germs before the formation of hard tissue. Deciduous and permanent teeth odontogenesis begins after the face has formed, either with or without the cleft. Discussion: The most acceptable hypothesis to enable understanding of the presence of supernumerary teeth on one or both sides of the cleft palate is hyperactivity of the dental lamina in its walls. This hyperactivity, with the formation of more tooth germs, must be attributed to mediators and genes related to tooth formation, under strong influence of local epigenetic factors, whose developmental environment was affected by the presence of the cleft. Conclusion: The current concepts of embryology no longer support the fusion of embryonic processes for the formation of the face, but rather the leveling of the grooves between them. All human teeth have a dual embryonic origin, as they are composed of ectoderm and mesenchyme/ectomesenchyme, but this does not make it easy for them to be duplicated to form supernumerary teeth.

Biostatistics: essential concepts for the clinician

ABSTRACT Introduction: The efficiency of clinical procedures is based on practical and theoretical knowledge. Countless daily information is available to the orthodontist, but it is up to this professional to know how to select what really has an impact on clinical practice. Evidence-based orthodontics ends up requiring the clinician to know the basics of biostatistics to understand the results of scientific publications. Such concepts are also important for researchers, for correct data planning and analysis. Objective: This article aims to present, in a clear way, some essential concepts of biostatistics that assist the clinical orthodontist in understanding scientific research, for an evidence-based clinical practice. In addition, an updated version of the tutorial to assist in choosing the appropriate statistical test will be presented. This PowerPoint® tool can be used to assist the user in finding answers to common questions about biostatistics, such as the most appropriate statistical test for comparing groups, choosing graphs, performing correlations and regressions, analyzing casual, random or systematic errors. Conclusion: Researchers and clinicians must acquire or recall essential concepts to understand and apply an appropriate statistical analysis. It is important that journal readers and reviewers can identify when statistical analyzes are being inappropriately used.

Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student’s t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

Factors associated with the morphology of the mandibular symphysis and soft tissue chin

ABSTRACT Objectives: This study aimed to (I) assess the morphology of the symphysis and soft tissue chin associated with sex, age and sagittal/vertical skeletal patterns, and (II) identify the individual and combined contributions of these variables to different portions of the symphysis. Methods: This cross-sectional study included 195 lateral cephalometric radiographs from untreated adults. Alveolar, basal, and soft tissue of the symphysis were measured by an X/Y cranial base coordinate system, and divided in accordance to four predictor variables: sex, age, and sagittal/vertical skeletal patterns. Parametric tests were conducted for comparison and correlation purposes, while multiple regression analysis was performed to explore combined interactions. Results: Alveolar inclination is related to sagittal and vertical patterns, and both explained 71.4% of the variations. Alveolar thickness is weakly predicted and poorly influenced by age. Symphysis height was 10% higher in males, and associated with a vertical skeletal pattern and sex, and both explained 43.6% of variations. Basal symphyseal shows an individual thickness, is larger in males, and vertically short-positioned with age. Soft tissue chin is not necessarily related to the size of the underling skeletal pattern, and enlarges with age, even in adulthood. Conclusions: The symphysis and surrounding tissues are influenced by sex, age, and sagittal and vertical patterns, acting differently on the alveolar, basal and soft tissue portions. Sagittal and vertical skeletal patterns are the strongest association on alveolar symphysis inclination, whereas sex and age acts on the vertical symphysis position and soft tissues thickness.

Orthodontist and periodontist’s knowledge, attitudes and aspects of clinical practice, regarding fixed lower orthodontic retainers

ABSTRACT Objective: This study aimed to assess the knowledge, attitudes, and aspects of the clinical practice of orthodontists and periodontists, regarding lower fixed orthodontic retainers. Methods: The orthodontists (n=502) and periodontists (n=269) who participated in this cross-sectional observational study received, via e-mail, questions related to the type of lower fixed retainer, dental biofilm accumulation, oral hygiene, and potential periodontal changes. The data were subjected to chi-square and Fisher’s exact tests, at 5% significance level. Results: Both orthodontists (72.3%) and periodontists (58.7%) reported that hygienic retainers accumulate more dental biofilm (p< 0.05), and 64.1% of orthodontists and 58.7% of periodontists considered that modified retainers may lead to periodontal changes (p< 0.05). There was no significant difference between the dental specialties, regarding the type of lower fixed retainer considered the easiest for the patient to perform hygiene (p> 0.05), whereas 48.6% of professionals chose the modified type. Conclusion: The modified retainer accumulates a greater amount of dental biofilm and, in the perception of orthodontists and periodontists, it may cause periodontal changes.

Effect of second molar eruption on efficiency of maxillary first molar distalization using Carriere distalizer appliance

ABSTRACT Introduction: Maxillary molar distalization is a common approach for correcting dental Class II malocclusions. Objective: This study aimed at comparing the outcomes of maxillary first molar distalization using the Carriere appliance before and after second molar eruption. Methods: Two groups of patients with dental Class II malocclusions were treated with Carriere distalizer appliance with heavy rectangular mandibular wire and lingual arch for anchorage. Patients of the first group presented unerupted maxillary second molars during the distalization period. In the second group, maxillary second molars were in occlusion on treatment onset. Cone beam computed tomography images were taken at the beginning of treatment and after finishing molar distalization, to compare both groups regarding first molar distalization, intrusion, mesiodistal tipping, buccolingual torquing and rotation, anchorage loss and skeletal changes. Also, the treatment durations were compared. Results: The mean first molar distalization period in the first group (19.2 ± 1.6 weeks) was significantly smaller than the second group (23.3 ± 2.3 weeks). The amount of maxillary first molar distalization was significantly greater, while the amount of rotation was significantly smaller in the first group. No statistically significant differences in the amounts of maxillary first molar intrusion, mesiodistal tipping and buccolingual torquing between both groups was found. Mandibular incisor labiolingual torquing and mandibular first molar mesialization and mesiodistal tipping were significantly greater in the second group. Conclusions: Maxillary first molar distalization before maxillary second molar eruption is more efficient, with less anchorage loss than after second molar eruption.

Stress and displacement of mini-implants and appliance in Mini-implant Assisted Rapid Palatal Expansion: analysis by finite element method

ABSTRACT Objective: In this study, simulations were performed by the finite element method (FEM) to determine the tension and displacement in mini-implants and in expander appliance during rapid maxillary expansion, by varying the number and location of the mini-implants. Methods: For the computational simulation, a three-dimensional mesh was used for the maxilla, mini-implants and expander appliance. Comparisons were made on six different Mini-implant Assisted Rapid Palatal Expander (MARPE) configurations, by varying the amount and location of mini-implants. A closed suture was design and received two activations of 0.25 mm, and an open suture had a 0.5-mm aperture that received 20 activations, also of 0.25 mm. Results: For the closed suture, the maximum displacement values in the mini-implants were between 0.253 and 0.280 mm, and stress was between 1,348.9 and 2,948.2 MPa; in the expander appliance, the displacement values were between 0.256 and 0.281 mm, and stress was between 738.52 and 1,207.6 MPa. For the open suture, the maximum displacement values in the mini-implants were between 2.57 and 2.79 mm, and stress was between 5,765.3 and 10,366 MPa; in the appliance, the maximum displacements was between 2.53 and 2.89 mm, and stress was between 4,859.7 and 9,157.4 MPa. Conclusions: There were higher stress concentrations in the mini-implant than in the expander arm. In the simulations with a configuration of three mini-implants, stress overload was observed in the isolated mini-implant. Displacements of the mini-implants and arms of the appliance were similar in all simulations.

Maxillary protraction and vertical control utilizing skeletal anchorage for midfacial-maxillary deficiency

ABSTRACT Introduction: The efficacy and efficiency of early treatment of skeletal Class III patients with facemask therapy are well-documented; however, very few cases for adolescents or adults were reported. Objective: The aim of this case report was to demonstrate skeletal and dental correction of a post-pubertal-growth-spurt patient whose malocclusion consisted of a skeletal Class III with slight transverse deficiency, a high mandibular plane angle, and a retrusive maxillary complex. Case report: A 13-year-5-months old Hispanic female was diagnosed as a retrognathic maxilla and mandible, a high mandibular plane angle, open bite pattern, a bilateral Angle Class I molar relationship with an anterior crossbite on the maxillary lateral incisors. A TAD-supported Haas rapid palatal expander was utilized for maxillary protraction combined with a facemask, vertical control, and maxillary molar distalization with fixed appliance. Results: The total treatment time was 26 months. An improved facial profile with maxillary lip support and more prominent cheeks was established. Adequate vertical control prevented a change in the mandibular plane angle even though facemask treatment can increase the vertical dimension. After the 18-month retention, excellent stability of the treatment results was shown. Conclusion: With skeletal anchorage and facemask treatment, orthodontists have the ability of expanding and protracting the maxilla without tipping maxillary molars buccally and without the risk of unfavorable periodontal consequences. A TAD-supported Haas rapid palatal expander allowed to control the vertical dimension and distalize molars, while minimizing undesired consequences.