Therapeutic reassessment of impacted or transposed teeth / Réévaluation thérapeutique des dents incluses ou transposées

Introduction: Impacted or transposed teeth present a common yet challenging issue in dentistry. These conditions occur when teeth fail to erupt properly or emerge in abnormal positions within the dental arch. Material and Method: This article explores the evolving landscape of therapeutic strategies for impacted or transposed teeth, emphasizing a multidisciplinary and patient-centered approach. Results: By adopting a multidisciplinary approach involving orthodontists, oral surgeons, and other dental specialists, clinicians can tailor treatment plans to address individual needs and optimize outcomes. Discussion: Therapeutic reassessment of impacted or transposed teeth represents a paradigm shift in modern dentistry, emphasizing personalized care, minimally invasive techniques, and interdisciplinary collaboration.

Introduction: Les dents incluses ou transposées présentent un problème courant, quoique difficile à gérer. Ces conditions surviennent lorsque les dents ne parviennent pas à faire leur éruption correctement ou émergent dans des positions anormales au sein de l'arcade dentaire. Matériel et méthode: Cet article explore le paysage évolutif des stratégies thérapeutiques proposées pour la prise en charge des dents incluses ou transposées, en mettant l'accent sur une approche multidisciplinaire centrée sur le patient. Résultats: En adoptant une approche multidisciplinaire réunissant des orthodontistes, des chirurgiens oraux et d'autres spécialistes dentaires, les cliniciens peuvent adapter les plans de traitement au mieux pour répondre aux besoins individuels de chaque patient et optimiser les résultats. Discussion: La réévaluation thérapeutique des dents incluses ou transposées représente un changement de paradigme en dentisterie moderne, mettant l'accent sur les soins personnalisés, les techniques mini-invasives et la collaboration interdisciplinaire.

Effect of power arm length combined with additional anterior torque on the axial orientation of the maxillary incisors during en-masse retraction: A finite element analysis.

INTRODUCTION: This study aimed to clarify the effect of power arm length combined with additional torque incorporated into the archwire on the controlled movement of the anterior teeth using the finite element method. METHODS: An adult patient requiring medium anchorage after extraction of the maxillary first premolars was selected for this study. The power arms were placed between the lateral incisor and the canine at 3 levels: 3 mm, 6 mm, and 9 mm. A 150 g of retraction force was applied from each height of the anterior hook to the first molar tube, with 0°, 5°, and 10° of applied lingual root torque on the incisors. RESULTS: A 3-mm hook with 10° of applied torque, a 6-mm hook with 5° of applied torque, or a 9-mm hook with no extra torque constituted the best combinations targeted at controlling the inclination of incisors during retraction. Extrusion and distal tipping of the canine were observed. Moreover, mesial tipping and mesiopalatal rotation of the molar were unavoidable. Finally, intercanine and intermolar widths were decreased. CONCLUSIONS: Adding extra torque on the incisors or using high torque brackets is recommended for patients with maxillary first premolar extraction.

Three-dimensional comparison of continuous and segmented arch techniques in the traction of palatally impacted canines using a non-linear finite element analysis.

OBJECTIVE: To compare the three-dimensional (3D) effects of canine traction on the maxillary teeth when using two different traction methods, the continuous and the segmented arch wire techniques; then to test whether adding a transpalatal arch (TPA) would affect their response to traction. DESIGN: Finite element analysis. METHODS: A cone-beam computed tomography (CBCT) scan of a patient with bilateral palatally impacted canines was chosen, from which a 3D model was derived and imported into ABAQUS. Two arch wires were modelled, a continuous round one and a segmented rectangular one. Four models were obtained by adding a TPA to both techniques. A 100° imposed rotation was then applied at the intersection between the vertical loop and the horizontal segment of each wire. Initial displacement of the maxillary tooth in the labio-lingual and in the vertical directions was measured. The absolute maximum principal stress of the periodontal ligament (PDL) was also assessed. RESULTS: Traction using a continuous arch wire led to different movement patterns of all teeth, some of them were tipped in a labial direction while others were lingually tipped. Traction using a segmented arch wire resulted in a retroclination of the posterior teeth and a proclination of the anterior teeth with a high level of stress on the premolars' PDL. Adding the TPA only affected the displacement of the first molars. The right side showed a maximum displacement of the first premolar, while the left side showed it on the lateral. The total displacement on the right side was higher than the left side. CONCLUSION: The segmented technique caused a uniform displacement of all teeth while the continuous one showed a non-uniform displacement. The angulation and position of the vertical loop affected the displacement of the maxillary teeth. The addition of a TPA acted only on the first molars.

Factors influencing the perception of profile beauty in Class III dental compensation: A comparative cross-sectional study according to three categories of assessors.

INTRODUCTION: The main objective of this study was to evaluate the different factors influencing the perception of female profile facial beauty in Class III patients with protruded mandible that can be treated with orthodontic dental compensation: (1)severity of the protrusion, (2) the upper incisors inclination and (3) the presence of jawlines. The secondary objective was to determine if the rater's gender and profession played a role in the assessment of the preferred profile. METHODS: A normal and smiling photographs of a female subject with normal facial and skeletal profile criteria were digitally manipulated to obtain 3 different mandibular sagittal positions: 0mm, +4mm and +8mm. Each position of the chin was evaluated with the presence or not of jawlines. In the smiling profiles, the same chin modifications were scored, and the maxillary incisor inclination was changed from 0 to +10 degrees with 5 degrees increments. A total of 320 raters (107 dentists, 103 orthodontists and 110 laypeople) scored the attractiveness of the different images using a Visual Analogue Scale. The limit of statistical significance was P<0.05. Generalized estimating equation (GEE) models were conducted to assess the predictors of variations in ratings within each set of photos, as well as the interactions of predictors where adjusted odds ratios (aOR) and their 95% confidence intervals were calculated and reported. RESULTS: In the profiles without a smile, image +4mm chin (Class III treated by compensation) and image +8-mm mandible (Class III not treated) were selected as the most and least attractive images, respectively, by almost all groups with no difference. The presence of jawlines has a positive role in facial attractiveness. In the smiling profiles, all the examiners showed a preference for image +4-mm chin and a slight protrusion of maxillary incisors (+5 degrees). No significant difference was found between genders in this study. CONCLUSIONS: Class III treated by compensation (+4mm) are more attractive than non-treated Class III (+8mm) by almost all groups with no difference. The presence of jawlines has a positive role in facial attractiveness. In the smiling profiles, all the examiners showed a preference for image +4-mm chin and a slight protrusion of maxillary incisors (+5 degrees). Orthodontists older than 50 years old are aware of the difficulty to treat a skeletal Class III and tend to accept it due to their long career experience. No significant difference was found between genders in this study.

Effect of Different Surface Treatments on the Shear Bond Strength of Metal Orthodontic Brackets Bonded to CAD/CAM Provisional Crowns.

BACKGROUND: The aim of this study was to find the best surface treatment for CAD/CAM provisional crowns allowing the optimal bond strength of metal brackets. METHODS: The sample consists of 30 lower bicuspids and 180 provisional crowns. The provisional crowns were randomly divided into six different groups. Orthophosphoric acid etching (37%) was applied to 30 lower bicuspids. The provisional crowns had undergone different surface treatments. Group 1: No treatment (Control Group). Group 2: Diamond bur. Group 3: Sandblasting. Group 4: Plastic Conditioner. Group 5: Diamond bur and Plastic Conditioner. Group 6: Sandblasting and Plastic Conditioner. The brackets in all groups were identically placed using Transbond XT® Primer and Transbond XT® Paste. Then, the entire sample underwent an artificial aging procedure, and a measurement of the bond strength was conducted. After debonding, the surface of the crowns was examined to determine the quantity of the adhesive remnant. RESULTS: Bonding to natural crowns recorded the highest average, followed by the averages of groups 5 and 6. However, group 1 recorded the lowest average. Groups 2 and 4 had very close averages, as well as groups 5 and 6. A statistically significant difference between the averages of all groups was recorded (p < 0.001) except for groups 2 and 4 (p = 0.965) on the one hand, and groups 5 and 6 (p = 0.941) on the other hand. DISCUSSION: The bonding of brackets on provisional crowns is considered a delicate clinical procedure. In fact, unlike natural crowns, the orthophosphoric acid usually used does not have any effect on the surface of provisional crowns. CONCLUSIONS: Using a diamond bur combined with the plastic conditioner and sandblasting combined with that same product resulted in a bond strength close to natural crown.

In-vivo durability of Pro Seal in patients with fixed orthodontic appliances: A controlled clinical trial.

BACKGROUND: This clinical trial aimed at studying the durability of an orthodontic sealant (Pro Seal) used on tooth surfaces for protection against white spot lesions. METHODS: A total of 35 patients (18 females, 17 males; 17.57 ± 1.36 years) were recruited. Eligibility criteria included healthy patients of both sexes (age > 14 years), absence of labial caries, absence of defective enamel, absence of extensive restorations, and optimum oral hygiene. The participants received a single application of Pro Seal on the bonded teeth. The sealant covered the labial enamel surrounding the brackets. Participants were recalled monthly after sealant application, during which sealant layers were evaluated using an ultraviolet lamp. The assessment was realized using an index similar to the adhesive remnant index (ARI). RESULTS: A total of 30 participants completed the trial. ARI values dropped significantly (P < 0.001) and reached <1.5 at T1 on the index used. An ARI value of 2 was chosen as the threshold below which a tooth presented an insufficient sealant layer. The right and left sides of both jaws did not show any statistically significant difference (P > 0.05). ARI values of homolateral teeth revealed few statistically significant differences between upper and lower teeth. No statistically significant difference between the two sexes (P > 0.05) existed. No harm or disturbance was reported by any of the participants. CONCLUSIONS: This study demonstrated that a single application of Pro Seal is effective for 4 weeks and should be renewed monthly. No interjaw, intrajaw, or intersex significant differences were found.

Cytotoxicity of V-Prep Versus Phosphoric Acid Etchant on Oral Gingival Fibroblasts.

The most used etchant in dental daily practice is the phosphoric acid (P.A.; 37%). However, acid etchants can induce necrosis on the oral mucosa and cause the ulceration of periodontal tissue when a rubber dam is not used. V-prep is a new practical alternative, and it has satisfactory results. It is used as a preparation before the application of a resin-modified glass ionomer composite (RMGIC) to bond the orthodontic brackets. The aim of this study was to investigate the effect of the V-prep on oral gingival fibroblasts cells by comparing the cell damage and cell viability after the use of V-prep and a conventional phosphoric acid etchant with different application times and concentrations. Therefore, Gingival fibroblasts passage 6 (GFP6) was grown and treated with an acid etchant and V-prep at three different concentrations (1:1, 1:2 and 1:10) for two different application durations (30 s and 1 min). The morphological changes, cell death and cell viability were assessed. Pyknosis, karyolysis, nucleus reversible and irreversible damages and membrane destruction were observed for both of the etchants at the higher concentrations and longer application durations. Mann-Whitney U-tests were used for the statistical analyses. The application of the V-prep for 30 s showed better values than the acid etchant did in the cell damage analysis and cell viability analysis (p = 0.03). V-prep at a 1:10 concentration applied for a 30 s duration can preserve the viability of gingival fibroblasts cells up to 100%. The toxicity of V-prep is equal or lower than the toxicity of the acid etchant that is commonly used in dentistry. Thus, the V-prep can be used with precautions intra-orally, and it should be applied on the enamel as a gel for 30 s only before it is rinsed and removed.

Evaluation of shear bond strength and adhesive remnant index of metal APC™ Flash-Free adhesive system: A comparative in vitro study with APC™ II and uncoated metal brackets.

OBJECTIVE: The aim of this in vitro study was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) of the metal APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. MATERIALS AND METHODS: One hundred eighty-six freshly extracted human premolars were randomly divided into 3 groups and bonded by a single operator. Group A/Control Group (60 teeth): the manual bonding group treated with Transbond™ XT Light Cure Adhesive Paste (3M™ Unitek). Group B (60 teeth): treated with APC™II metal maxillary premolar precoated brackets. Group C (66 teeth): treated with metal maxillary premolar APC Flash-Free brackets. The teeth were then stored in distilled water at 37̊C for 24hours, and five hundred cycles of thermocycling were performed. The Shear Bond Strength (SBS) test was performed using an Instron Universal Testing Machine, and the adhesive remnant index (ARI) was determined using a dental optical microscope at ×25 magnification. RESULTS: The mean shear bond strength values showed differences between the three types of brackets (P=0.016; Anova). It was significantly higher with APC™II and lower with APC Flash-Free brackets; however, no significant differences were found between conventional and APC Flash-Free brackets (P-value=0.574). The distribution of the dichotomized ARI score was significantly different between the three brackets (P-value=0.049). The ARI score for APC Flash-Free brackets was higher with no significant difference between the conventional system and APC brackets (P-value=0.361). CONCLUSIONS: The mean SBS values were not significantly different between APC Flash-Free metal brackets and uncoated metal brackets. The APC Flash-Free metal system's bond failure occurred at the bracket-adhesive interface, with the highest percentage of teeth having more than 50% of the residual composite on the enamel after debonding.

Comparative study of excess glue around metallic APC™ Flash-Free adhesive system / Étude comparative des excès de colle autour des attaches métalliques préencollées APC™ Flash-Free

Introduction: The aim of this in vitro study was to determine if there is a significant difference in the excess adhesive flash between the metallic APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. Materials and Methods: One hundred eighty-six freshly extracted human premolars were randomly and blindly divided into three groups according to the type of brackets. Group A (control group n=60): The conventional uncoated metallic bracket (Victory, 3M Unitek®) with a Transbond XT™ Light Cure Adhesive Paste was used. Group B (n=60): The APC™ II metallic maxillary precoated premolar brackets was used. Group C (n=66) : The metallic APC™ Flash-Free adhesive system without flash clean up was used. Images were taken at 40 magnifications in a dental microscope (Leica M320 for dental, Wetzlar, Germany) then analyzed with the ImageJ software and the area of excess adhesive flash was measured. Results: The mean percentage was significantly different between the three groups (p<0.001; ANOVA). It was significantly smaller for brackets in the APC Flash-Free group (p<0.001), and the difference was not significant between conventional brackets and APC (p=0.224). Discussion: The new technique seems to reduce the amount of excessive adhesive around orthodontic brackets.

Introduction: L'objectif de cette étude in vitro était de présenter une évaluation comparative et objective de l'efficacité d'une nouvelle technique d'attaches métalliques préencollées APC™ Flash-Free fabriquées par 3M Unitek®, éliminant l'étape de nettoyage grâce au système de fibres non tissées. Matériels et méthodes: Cent quatre-vingt-six prémolaires humaines saines fraichement extraites sont réparties en trois groupes de façon randomisée. Groupe A : 60 dents sont collées avec des attaches conventionnelles à encoller avec du Transbond XT™ (3M Unitek®). Groupe B : 60 dents sont collées avec des attaches préencollées APC™ II préenduites du même type de pâte adhésive. Groupe C : 66 dents sont collées avec des attaches APC™ Flash-Free (3M Unitek®), puis observées avec un microscope (Leica M320 for dental, Wetzlar, Germany) sous un agrandissement x40. Les photographies sont analysées à l'aide du logiciel ImageJ. Résultats: Les comparaisons multiples de Tukey ont montré que le pourcentage moyen était significativement plus petit au niveau des attaches du groupe C, APC™ Flash-Free (p-value<0,001), mais la différence n'a pas été significative entre les attaches conventionnelles du groupe A et celles préencollées du groupe B (p-value=0,224). Discussion: La technique de pointe adoptant un matériau non-tissé a l'air de réussir à réduire l'excès d'adhésif périphérique.

Three-dimensional comparison of the effects of sliding mechanics in labial and lingual orthodontics using the finite element method.

INTRODUCTION: The extraction of maxillary first premolars is usually the treatment of choice to resolve crowding, alveolar protrusion, or Class II malocclusion. The demand for a lingual orthodontic treatment is increasing because of its esthetic value; therefore, understanding lingual biomechanics is essential to every clinician. This study compared the 3-dimensional (3D) effects of sliding mechanics in labial and lingual orthodontics using the finite element method. METHODS: Twelve 3D finite element models were created with different power arm heights and miniscrew positions. A 150 g of retraction force was applied from the head of the miniscrew to the power arm. The 3D displacement of the original nodes was measured, and the stress distribution on defined element zones of the periodontal ligament. RESULTS: Different force directions led to different movement patterns and stress distribution. The lingual models showed a more important lingual crown tipping, extrusion, and higher stress values than the labial models. Results were not affected by the vertical position of the miniscrew. CONCLUSIONS: Bodily en-masse retraction was not achieved in all models. Adding extra torque to the archwires is essential to prevent excessive lingual crown tipping. The lingual appliance induced more lingual tipping and extrusion of the anterior teeth. Expanding the archwire is important to minimize the risk of intercanine width reduction. The vertical position of the miniscrew does not affect the results of en-masse retraction.

Effects of enamel deproteinization with different application times on the shear bond strength of a self-etching primer: An in vitro study.

OBJECTIVE: The aim of this in vitro study was to evaluate the effects of enamel deproteinization on the shear bond strength of a self-etching primer Transbond Plus™(TBP), with different application times of sodium hypochlorite (NaOCl 5.25%), primarily and secondarily on the adhesive remnant index score. MATERIALS AND METHODS: One hundred twenty-five freshly extracted human premolars were randomly and blindly divided into five groups according to the enamel surface preparation, as follows (n=25): group 1(control): Etching with 37% phosphoric acid for 15seconds+Bonding; group 2 (control): TBP™ without NaOCl, group 3: 60seconds NaOCl+TBP™, group 4: 30seconds NaOCl+TBP™, group 5: 15seconds NaOCl+TBP™. The same composite resin was used (Transbond XT™) to bond the orthodontic metal brackets. After the immersion of the teeth in distilled water at 37°C for 24hours the shear bond strength was measured using the universal testing machine and the adhesive remnant index score (ARI) was evaluated under an optical microscope (25×). RESULTS: The mean SBS values (inMPa) of the groups were respectively: group 1: 13.03±5.36; group 2: 12.28±3.06; group 3: 12.38±4.55; group 4: 12.98±5.76; and group 5: 11.73±5.67. Enamel deproteinization increased the SBS for groups 3 and 4, but no statistically significant difference was found between the five groups (P=0.883). Group 1 showed the highest ARI scores, with 52% of the teeth retaining all the adhesive (score 3). However, for all the other groups, scores 0 and 1 were predominant, with less than half of the adhesive or no adhesive at all remaining on the teeth. CONCLUSIONS: Enamel deproteinization with sodium hypochlorite (5.25%) and the variation of its application time has no effect on the SBS of the self-etching primer Transbond Plus ™.

Evaluation of the distance between the root apices of the upper first molars and the hard palate in an Eastern Mediterranean population: A retrospective study.

OBJECTIVE: The aims of this retrospective study were, first to evaluate the distance between the root apices of the upper first molars and the palatal plane (PP), and second to determine the validity (accuracy) of the use of cephalometric radiographs or panoramic X-rays compared to cone beam computed tomography (CBCT) in determining this distance. MATERIAL AND METHODS: The distance was calculated from the root apices of the first molars to PP, on the cephalometric radiographs of 204 subjects and then 57 measurements were compared to those obtained on panoramic X-rays and CBCT images, in order to find a statistically significant difference according to age, sex, side, vertical and sagittal skeletal patterns, and to determine if 2D radiographs are suitable for this task. RESULTS: The distance increased significantly in subjects after 20 years of age and in hyperdivergent patients, but was not influenced by sex, side or anteroposterior position of the mandible. No statistical significance was found between the calculated measurements on cephalometric and CBCT radiographs, but both were different from those taken on panoramic X-rays. CONCLUSIONS: Cephalometric radiographs are reliable in the assessment of the distance between the roots of the upper molars and the PP. In hyperdivergent and adult patients, posterior teeth have enough space between their roots and the upper limit of the hard palate to undergo intrusion mechanics using miniscrews, but care must be taken while planning and managing these movements in order to minimize the unwanted side effects.

[Impact of orthodontic treatment and psychological parameters on oral health related quality of life of children in Middle Eastern country]. / Impact du traitement orthodontique et des paramètres psychologiques sur la qualité de vie liée à la santé orale chez les enfants au Moyen-Orient.

This study is aimed at evaluating the Oral Health Related Quality of Life (OHRQoL) in adolescents aged 11-14 years-old during orthodontic therapy and 18 months after the start of treatment and the possible role of psychological parameters. Sixty patients were recruited, and data were collected using self-administrated questionnaires and intraoral clinical examinations. The questionnaires included sociodemographic characteristics (age, gender), the Lebanese version of the Child Perception Questionnaire between 11 and 14 years CPQ11-14 to assess the OHRQoL, the Discrepancy Aesthetic Index (DAI) for malocclusion, and the Child Health Questionnaire « CHQ-CF87 ¼ to appraise Self-Esteem (SE) and Psychological Well-Being (PWB). The mean scores of CPQ11-14 and its four subdomains were significantly better for participants with high SE /PWB compared to those with low SE / PWB at baseline. These same scores improved significantly during orthodontic treatment (p < 0.001). However, DAI was significantly better in patients with low self-esteem and psychological well-being. Our findings showed improvement in oral health perception and psychologic parameters during orthodontic treatment. Investigators should consider the need to control the psychological parameters of patients when assessing orthodontic treatment need and improvement in OHRQoL during orthodontic treatment.

Changes of arch form at the end of orthodontic treatment, based on the Ricketts pentamorphic arch forms.

INTRODUCTION: Maintenance of the intercanine and intermolar distances reduces the risk of relapse and increases the chance of stability; these values represent the limits of the arch, resulting from the muscular balance of each patient. The ideal would be to reproduce the patient's arch form individually. The Ricketts pentamorphic arch forms allow the clinician to choose among 5 shapes, the one that best fits the patient's arch form. The objective of this study was to evaluate the effect of orthodontic treatment without extraction according to the pentamorphic arch forms on mandibular arches of different forms. METHODS: Fifty patients were included in the study. For each patient, the pretreatment and end-of-treatment models were scanned by 3Shape Trios (3Shape, Copenhagen, Denmark) and transferred to the OrthoAnalyzer software (3Shape) version 2017-11.7.1.3 for measurements and superimpositions. The following measurements were made on the mandibular arches for both initial and final digital models: arch depth; intercanine distance, the distance between the first premolars, the distance between the second premolars, the distance between the first molars, and the distance between the second molars. Three superimpositions were made: superimposition between the initial arch and the corresponding form of the pentamorphic arch forms, superimposition between the final arch and the corresponding form of the pentamorphic arch forms, and superimposition between the initial arch and the final arch. The largest difference between the superimposed arches in each region was measured. RESULTS: This study showed that intercanine distance (P = 0.236), the distance between the first premolars (P = 0.074), and the distance between the first molars (P = 0.616) did not significantly change after orthodontic treatment. In contrast, the distance between the second molars (P = 0.028) and the arch depth (P <0.001) increased significantly after orthodontic treatment. The mean of the largest difference in the absolute value of all the superimpositions is significantly different from the theoretical value 0 (P <0.001), but clinically, this difference is significant only in certain premolars and molars regions. CONCLUSIONS: This study has shown that the pentamorphic arch forms maintained the arch shape in the sagittal and transverse directions, except for an expansion of the distance between the mandibular second molars.

Correlation between fusion of spheno-occipital synchondrosis and cervical vertebral maturation: A CBCT and cephalometric assessment.

OBJECTIVE: The aim of this study was to determine among young orthodontic patients the relation between the spheno-occipital synchondrosis (SOS) fusion and the cervical vertebral maturation (CVM) and to look for an eventual impact of gender, skeletal class and vertical pattern on their association. MATERIAL AND METHODS: CBCT scans and lateral cephalometric radiographs of 117 patients, aged between 8 and 18 years, were selected. SOS fusion was assessed on a mid-sagittal cut of the CBCT scans. CVM was evaluated on the lateral cephalograms as well as ANB and GoGn-SN angles. Spearman correlation test was used to assess the relationship between SOS and CVM. Fisher's exact test was performed at every CVM stage to analyse the association between SOS and other variables (gender, skeletal class, and vertical pattern). Cohen's kappa analysis was used for reliability. RESULTS: A strong correlation was found between SOS maturation and CVM (r=0.852, P<001). Fisher's exact test indicated significant association only between gender and SOS in CVM stage 2 group, and between vertical pattern and SOS in CVM stage 4. Cohen's kappa analysis showed moderate inter and intra-rater reliability for CVM index (k=0.50 and 0.53 respectively, P<.001), strong inter-rater reliability (k=0.80, P<.001) and almost perfect intra-rater reliability (k=0.85, P<.001) for SOS index. CONCLUSIONS: SOS fusion correlates well with CVM and might be a reliable tool for skeletal maturation assessment. Girls seem to have an earlier fusion of SOS in relation to their respective CVM compared to boys, and the vertical pattern could influence the association between SOS and CVM stages.

Evaluation of the ideal position of the maxillary incisor relative to upper lip thickness.

INTRODUCTION: The anteroposterior position of the maxillary incisors has been studied since the beginning of cephalometric research. Most reports of ideal position have been based on measurements made on subjects with Class I occlusion without consideration of other facial variables. However, the ideal position is reflected in the soft tissues by the position of the lips. The purpose of this study was to consider the position of the maxillary incisor relative to other factors, including the thickness of the upper lip, and to evaluate its most aesthetic position using profile photographs. METHODS: The subjects in this study were 130 patients with Class I occlusion; their sex, age, thickness of the upper lip, and angular position of the maxillary incisor were recorded. From these 130 patients, 70 profile photographs that met the inclusion criteria were chosen for further evaluation. A survey was conducted among 60 lay people, 60 dentists, and 60 orthodontists. They were asked to classify the sets of photographs, from the most esthetic position of the upper lip to the least esthetic. RESULTS: For patients with thin lips, raters tended to prefer a more protruded position of the incisor than normal or between 8.0 mm and 11.5 mm in front of the Na-B bone and 4 mm in front of the Na-A bone. For patients with thick lips, the position of the incisor did not affect the perception of the profile. CONCLUSIONS: A correct skeletal scheme or Class I occlusion does not necessarily result in ideal facial harmony. Therefore, it will be necessary to consider all the factors that come into play, especially the lips, which are a key element in facial esthetics.

A comparison between RMGIC and composite with acid-etch preparation or hypochlorite on the adhesion of a premolar metal bracket by testing SBS and ARI: In vitro study.

OBJECTIVE: A bonding material can be acceptable in orthodontics when Shear Bond Strength (SBS) is higher than 5.9Mpa. The aim of our study was to compare the bonding of a metal orthodontic bracket "in vitro" under different types of healthy enamel surface preparations and with two bonding products: the composite and the Resin Modified Glass Ionomer Cement (RMGIC). METHODS: Premolars preserved in 1% thymol water were bonded on their vestibular and palatal/lingual surfaces with different techniques of bonding and surface preparation: Group 1: Etching+Bonding+Composite, Group 2: Etching+Fuji Ortho LC, Group 3: V-prep+Fuji Ortho LC, Group 4: V-prep+Fuji Ortho LC+Thermocycling. The SBS was measured in Newton on the universal testing machine and the sample was observed under an optical microscope with 10-fold magnification to note the adhesive remnant index score (ARI), before and after thermocycling. RESULTS: 120 premolars were used in this study. RMGIC bonding was significantly increased when the surface was prepared at V-prep (P<0.001). In these conditions, RMGIC bonding on the buccal surface was similar to that of the composite and superior on the palatal/lingual surface (P=1). After 2 years of aging using a thermocycling machine for simulation, RMGIC bonding significantly decreased (P<0.001). The ARI score was significantly lower for the RMGIC group than the composite group (P<0.001). CONCLUSIONS: RMGIC bonding with V-prep preparation is recommended for palatal/lingual surfaces and for hard-to-dry surfaces. For vestibular surfaces, studies are still needed to recommend bonding with RMGIC instead of composite.

Estimation and Comparison of the Duration of the Pubertal Peak in Skeletal Class II and Class I Subjects Using the Cervical Vertebrae Maturation Index Method.

AIM: The purpose of this study is to estimate and compare the duration of the pubertal peak in skeletal class II and class I subjects and to detect any difference between boys and girls or between hypo-, normo-, and hyperdivergent subjects for skeletal maturation indicator (CVM) in white Caucasians. MATERIALS AND METHODS: 346 subjects were selected from 3,119 examined files. Pretreatment lateral cephalometric records were hand-traced and divided following the anteroposterior skeletal relationship, the gender, the vertical pattern, and the skeletal maturation. The duration of the pubertal peak was calculated based on the chronological age interval according to each group. The age of onset of the active growth and the duration of the pubertal peak were compared between the different groups studied. RESULTS: Pubertal peak had a mean duration of 13 months in skeletal class I subjects, 19 months in skeletal class II subjects, 15 months in girls, 20 months in boys, 13 months in normodivergent and hypodivergent subjects, whereas in hyperdivergent subjects, it lasted 18 months. CONCLUSION: The growth interval corresponding to the pubertal growth spurt (CS3-CS4) was (1) significant between skeletal class I and class II subjects, (2) longer in boys, and (3) longer in hyperdivergent subjects. CLINICAL SIGNIFICANCE: Orthodontic treatments can start earlier for girls in class I or class II relationship and for hyperdivergent subjects as well. Furthermore, boys and subjects in class II skeletal relationship have a significantly longer duration of the pubertal peak and consequently a much efficient orthopedic and orthodontic treatment.

Variation of upper lip pressure on upper teeth during non-extraction orthodontic treatment: A prospective clinical study.

OBJECTIVE: The objectives of this prospective clinical study are to quantify the variation of pressure exerted by the upper lip on the upper teeth during the alignment phase and to evaluate its capacity to adapt to changes in dental position. MATERIALS AND METHODS: Thirty young subjects in skeletal Class I relationship requiring non-extraction orthodontic treatment were included in this study. The pressure exerted by the upper lip on the upper central incisors and right canine were measured during rest and swallowing positions using a pressure transducer before bracket placement (T0), after bracket placement (T1), three months (T2) and six months later (T3). Maxillary intercanine width (CC), upper arch length (U) and crowding (C) were measured on stone models at T1, T2 and T3 to determine the existence of a correlation between the variation of lip pressure and these variables. RESULTS: The lip pressure significantly increased after bracket placement and remained relatively stable during the six-month period. The labial pressure on the incisors was the only variable to significantly decrease at T3, though remaining significantly higher than the starting pressure. A positive correlation was found between the variation of the inter-canine distance and the labial pressure on the canine at rest whereas a negative correlation exists between the crowding and the labial pressure on the incisors at rest. CONCLUSION: This study showed that increasing inter-canine width disrupts the muscle equilibrium and therefore is prone to relapse, whereas the upper lip can better adapt to the protrusion of upper incisors.