Late Mixed Dentition Stage Research Articles

Scope of clear aligner therapy (CAT) in Phase I (early) orthodontic treatment

Phase I (early) orthodontic treatment is intended to correct developing skeletal, dentoalveolar, and muscular imbalances, and to improve the orofacial environment before the permanent teeth eruption. The orthodontic intervention in mixed dentition provides orthodontist a unique opportunity to apply their reasoning and understanding in addressing an impending malocclusion and avoid or limit the use of Phase II treatment. This paper describes the application of clear aligner therapy (CAT) in growing individuals. The use of clear aligner treatment in addressing early transverse discrepancy (inter- and intra-arch), Class III and Class II malocclusion are discussed in the light of current available evidence, and through case discussion. The authors propose treatment options for the correction of vertical and transverse malocclusion during early and late mixed dentition stage. Furthermore, the barriers and enablers of compliance in Phase I therapy are explored and possible resolutions are discussed. In summary, Phase I orthodontic treatment using CAT lack a large body of credible evidence, nonetheless, it is proving to be an exciting field regarding its sheer scope and expanse.

A Study on the Significance of Orthodontic Treatment among Bangladeshi School Children

Introduction: The treatment of malocclusion places a considerable burden on health care resources globally, particularly when funded by public means. In an attempt to prioritize the treatment of malocclusion, various occlusal indices have been developed based on the severity of malocclusion and/or the conceivable destruction it may cause to oral health if left untreated. However, it has been recognized that perhaps people seek and undergo orthodontic treatment not because of anatomic irregularities, but because of the consequences of the esthetic impairment caused by a malocclusion. Thus, malocclusion and orthodontic care have become a quality-of-life issue. This study aimed to assess the significance of orthodontic treatment according to an index (Index of Orthodontic Treatment Need) among Bangladeshi school children in the late mixed dentition stage. Methods: This Cross-sectional descriptive study was conducted at the Ideal School, Banasree Project, Rampura, Dhaka, and Faizur Rahman Ideal School, Banasree, Dhaka, Bangladesh. The study was conducted from 25th September 2010 to 25th January 2011. A total of 126 school children were included in this study. Result: Among 126 school children, 39.68% belonged to the age of 10, 24.61% were the age of 11, and the rest 35.71% belonged to the age of 12. The study showed male predominance, having 75 (59.52%) males and 51 (40.48%) females. Among the study population, 19% of the children came from a family whose monthly income was 20000tk, while 13.50% and 11.90% of the children belonged to families whose income were 18000tk and 15000tk respectively and the rest of the families whose parent’s monthly income was less than 15000tk. About 50% of school students were diagnosed as Grade 1, 22.2% were in Grade 2, 24.6% were in Grade 3, 1.6% was in Grade 4 and 1.6% were in Grade 5. 28 respondents of age 10 years; 10 respondents of age 11 years; 25 respondents of age 12 years needed no treatment. 11 respondents of age 10 years; ......

Perspectives of Indonesian Orthodontists on the Ideal Orthodontic Treatment Time.

ObjectiveThe aim of this study was to explore the types of orthodontic treatment provided by Indonesian orthodontists and to analyse their perspectives on the ideal time to initiate orthodontic treatment.Materials and MethodsA cross‑sectional survey was conducted using the Google Drive questionnaire template. This electronic questionnaire was sent to a sample of orthodontists across different regions of Indonesia. The participants were asked to report the stage at which they would start orthodontic treatment, as well as answer questions about occlusal abnormalities and functional problems. Descriptive statistics for all variables were determined, including both practice characteristics and orthodontic treatment timing.ResultsA total of 152 orthodontists agreed to participate in the study, of which 64.5% were female and 35.5% were male. Indonesian orthodontists prefer two-phase orthodontic treatment. Sucking habits and open bite were found to be the most frequent indications for treatment in the primary dentition. Anterior crossbite was found to be the most frequent indication for treatment during the early mixed dentition stage. Severe Class II was found to be the most frequent indication for treatment during the late mixed dentition stage. Indonesian orthodontists are more concerned about impacted canines and midline diastema than other occlusal deviations in the permanent dentition.ConclusionBased on the results of this study, we can conclude that Indonesian orthodontists favor two-phase orthodontic treatment. They also prefer to treat sucking habits and open bite in the primary dentition, anterior crossbite in the early mixed dentition, and severe Class II during the late mixed dentition stage.

Age‐related changes in oral motor‐control strategies during unpredictable load demands in humans

To investigate age-related changes in oral motor strategies in response to unpredictable load demands. Sixty-five healthy children (aged 3-17yr) were divided into five age-groups based on their dental eruption stages and compared with a group of healthy adults (aged 18-35yr). Each participant was asked to perform a standardized motor control task involving 'pulling' and 'holding' a force transducer with the anterior teeth. Different loads were attached to the force transducer in an unpredictable manner. The temporal force profile was divided into two time-segments (an initial segment and a later segment). The peak force and peak force rate during the initial time-segment, and the holding force and intra-trial variability (coefficient of variation) during the later time-segment, were measured. The results showed no differences in the peak force, peak force rate, holding force, and force variability in children compared with adults. However, the trends in the data evaluated using a segmented regression analysis showed that a breakpoint (abrupt change) consistently occurred in the late-mixed dentition group (age 9-11yr) for most of the outcome variables. The results indicate that while the motor control strategies in children appear to be similar to those in adults, there is a shift in the oral motor developmental trend during the late-mixed dentition stage.

Evaluation of Growth and Development of Late Mixed Dentition Upper Dental Arch with Normal Occlusion Using 3-Dimensional Digital Models.

Objective The purpose of this study was to observe the three-dimensional growth and development of the maxillary arch in 10-year-olds with normal occlusion during the late mixed dentition stage. Methods Forty-four 10-year-old students (22 males and 22 females) who had normal occlusion during late mixed dentition were selected from an elementary school in Beijing, China. Once per year for three consecutive years, a dental cast was obtained from each subject, and the cast was scanned with a 3D digital scanner (R700 3D). The three-dimensional measurements of the maxillary dental arch and the inclination of the bilateral maxillary first molars were obtained from the digital model. Results The upper anterior arch length (UAAL), upper total arch length (UTAL), upper inter primary or permanent canine width (UICW), upper intermolar width (UIMW), and upper dental arch length (UDAL) increased by 0.959 mm, 0.583 mm, 0.955 mm, 1.462 mm, and 2.46 mm, respectively, over the two years (P < 0.001). UR6BL and UL6BL decreased by 4.416° and 7.133°, respectively, over the two years (P < 0.001). The values of the UICW and UIMW were 1.67 mm and 1.86 mm, respectively, larger in males than in females at 12 years old (P < 0.01). The change in the UTAL was 0.431 mm greater in males than in females over the 2 years (P < 0.05). Conclusion The UAAL, UTAL, UICW, UIMW, and UDAL in 10- to 12-year-olds with normal occlusion increased with age. The buccolingual inclination of the bilateral maxillary first molars inclined to the palatal side with age. The UICW and UIMW were larger in males than in females at 12 years old. The male UTAL increased more than the female UTAL over the 2 years.

Treatment effects of two different appliances on pharyngeal airway space in mixed dentition Malay children

BackgroundTreatment of Class III malocclusion is related to redirecting the growth of mandible, which may have an impact on the pharyngeal airway. ObjectiveTo evaluate and compare the treatment effect of Reverse Twin-Block (RTB) and Reverse Pull Face Mask (RPFM) on Pharyngeal Airway Space (PAS) in early and late mixed dentition Class III samples. MethodsNinety-five mixed dentition Malay children with Class III malocclusion were included in this study. Data consists of 190 pre- and post-treatment lateral cephalograms of early (8–9 years) and late (10–11 years) mixed dentition Class III samples. forty-nine samples were under RTB and forty-six samples were under RPFM. Treatment changes were evaluated by McNamara airway analysis and changes in tongue and hyoid bone position. ResultsBoth upper and lower pharyngeal airway width were increased after treatment with RTB and RPFM ruling out the chance of airway constriction. There was also posterior positioning of the tongue and hyoid bone indicating mandibular retrusion. No significant treatment changes were found on the Pharyngeal Airway Space by the factor age, gender or type of appliance. ConclusionsBoth RTB and RPFM increased the Pharyngeal Airway Space and produced similar treatment effect. As age does not affect the treatment outcome significantly, treatment can be delayed until late mixed dentition stage.

Early treatment of class II division 1 malocclusion by R- appliance

Purpose: The purpose of this study was to assess the dentoskeletal effects of R-appliance in treatment of patients with Class II division1 in the late mixed dentition stage. Methods and Material: The sample included twelve cases (6 females and 6 males), with average age of 10.5 years, who were treated by R-appliance for 12 months. All cases had malocclusion Class II division 1 due to mandibular retrusion. Lateral cephalograms were taken and analyzed before and after the treatment to evaluate the efficacy of the appliance. Result: statistical analysis using the SPSS version 20.0 revealed that there was highly significant increase in SNB angle by 4.14 mm (P

Treatment effects of Reverse Twin-Block and Reverse Pull Face Mask on craniofacial morphology in early and late mixed dentition children.

Reverse Twin-Block (RTB) and Reverse Pull Face Mask (RPFM) appliances are used to correct Class III malocclusion in growing patients. Aim of this retrospective study was to compare and analyse craniofacial changes produced by RTB and RPFM in the early and late mixed dentition in Malay children with Class III malocclusion. Data consisted of pre- and post-treatment lateral cephalograms of 95 children, 49 patients with RTB and 46 patients with RPFM, divided into an early (8-9year) and late (10-11year) group. Treatment changes were assessed by the Ricketts analysis using CASSOS software, where 71 anatomic landmarks were identified in each cephalogram. Paired and independent t tests were performed for statistical comparison. Paired t test revealed significant changes in facial axis, facial angle, MD plane to FH, lower facial height, mandibular arc, maxillary convexity, U1 to APog, L1 to APog, L1 to APog angle and upper lip to E-plane measurements in RPFM, whereas significant changes were found in facial taper, U1 to APog and lower lip to E-plane values with RTB in the early treatment group. Independent t test revealed significant changes in U1 to APog, L1 to APog and U6 to PtV values in the RTB group. Post-treatment comparison of RTB and RPFM showed significant differences in L1 to APog and L1 to APog angle values. RPFM revealed more favourable craniofacial changes than RTB, particularly in the late mixed dentition stage.

Prevalence of infraocclusion of primary molars determined using a new 2D image analysis methodology.

The reported prevalence of infraocclusion varies widely, reflecting differences in definitions and measurement/scoring approaches. This study aimed to quantify the prevalence and extent of infraocclusion in singletons and twins during the late mixed dentition stage of dental development using a new diagnostic imaging method and objective criteria. The study also aimed to determine any associations between infraocclusion and gender, arch type, arch side and tooth type. Two samples were analysed, 1454 panoramic radiographs of singletons and 270 dental models of twins. Both samples ranged in age from 8 to 11 years. Adobe Photoshop CS5 was used to measure the extent of infraocclusion. Repeatability tests showed systematic and random errors were small. The prevalence in the maxilla was low (<1%), whereas the prevalence in the mandible was 22% in the singleton sample and 32% in the twin sample. The primary mandibular first molar was affected more often than the second molar. There was no significant difference in the expression between genders or sides. A new technique for measuring infraocclusion has been developed with high intra- and interoperator reproducibility. This method should enhance early diagnosis of tooth developmental abnormalities and treatment planning during the late mixed dentition stage of development.

Endodontie im Kindes- und Jugendalter — Grenzen der Zahnerhaltung

BackgroundThe limitations of endodontic procedures in childhood and adolescence arise from general and special aspects at this age. The preservation of primary teeth during the pre-school age could be challenging due to the facts that these procedures are usually compliance related procedures and due to the dental physiological changes happening during the early mixed dentition phase, in the late mixed dentition stage and after the full development of dentition some technical (local) problems start to manifest especially in nonvital permanent teeth with incompletely formed roots.RecommendationIn particular cases the clinical indications along with individual tooth situations should be balanced, whether or not the endodontic procedure is reasonable in terms of cost-effect and associated risks for the patient. Some considerations should be taken during treatment planning; primary teeth should have a transitional character type of treatment, as for permanent teeth a long term prognosis should be taken in account. At selected clinical examples such limitations should be identified.

Occlusal status among Yemeni children

Objectives: The purpose of this study was to assess the occlusal status in schoolchildren in Yemen, and to compare the results with those of other studies. Materials and Methods: The sample for this epidemiological survey consisted of 3003 primary school students, half of whom were boys and the other half girls, aged 12 years. The subjects were randomly selected, and none had received previous orthodontic treatment. Variables examined included intra-arch irregularities and malalignment (crowding and spacing in the incisal segments of the arch and midline diastema) and discrepancies in occlusal contact relationship (maxillary overjet, mandibular overjet, anterior openbite and antero-posterior molar relation). Results: The results showed that about 26.1% of the subjects were still in the late mixed dentition stage and 73.9% presented with a dentition in the early permanent stage. Normal overjet was found in 55% of the sample. Crowding was observed in 31.4% of the subjects and midline diastema in 14.2%. Conclusion: Occlusal status among Yemeni children was characterized by a relatively high frequency of dental crowding, as well as a relatively high frequency of anterior mandibular overjet (Class III malocclusions).

Twenty -year post-treatment assessment of class II division 1 malocclusion treated with non-extraction approach

Several treatment strategies exist to deal with class II division 1 malocclusions depending upon the configuration of the malocclusion and the age of the patient. The results produced by one or a discretionary combination of these treatment modalities can only be considered satisfactory if they remain stable, making long-term stability a main objective of orthodontic treatment. To achieve long-term stability, several different treatment techniques and philosophies have been recommended; however, despite many efforts to achieve this goal, a definitive treatment protocol is still lacking. This article describes twenty-year post-treatment assessment of a class II division 1 malocclusion case, treated in the late mixed dentition stage, with the non-extraction treatment approach - molar-inserted headgear along with a fixed appliance therapy.

Maximum occusal bite force for children in different dentition stages

This study was carried out to record maximum occlusal bite force (MOBF) among different dentition stages in children and to study the relation of occlusal bite force to weight, height, and gender. A total of 1011 children (500 females and 511 males) aged from 3 to 18 years were examined. The subjects were divided into 5 groups according to their dentition stage as the following:- early primary dentition stage (100 males and 100 females, average age was 3.37 ± 0.23 years), late primary dentition stage (104 males and 100 females, average age was 5.86 ± 1.15 years), early mixed dentition stage (100 males and 100 females, average age was 8.15 ± 0.67 years), late mixed dentition stage (100 males and 100 females, average age was 9.97 ± 0.86 years ), and permanent dentition stage (107 males and 100 females, average age was 14.03 ± 2.14 years). Occlusal bite force was measured using a hydraulic occlusal force gauge. The means of MOBF for the different dentition stages were:- 176 N in early primary stage, 240 N in late primary stage, 289 N in early mixed stage, 433 N in late mixed stage, and 527 N in the permanent dentition stage, respectively. Gender differences were detected in groups 2, 3 and 4. Height and age significantly correlated with the MOBF in all dentition stage groups except group 1. In conclusion, the MOBF increased with age. Age, gender, and height were significant predictors of the MOBF.

The need for orthodontic treatment among 10–11- and 14–15-year-old Lithuanian schoolchildren

The aim of this study was to evaluate the need for orthodontic treatment among 10-11- and 14-15-year-old schoolchildren in Lithuania. MATERIAL AND METHODS. A total of 4235 children randomly selected from different socioeconomic backgrounds were examined. The schoolchildren were divided into two age groups: first group, 10-11-year olds (1142 boys, 1180 girls) and second group, 14-15-year olds (936 boys, 977 girls). The normative orthodontic treatment need was assessed using the Index of Complexity, Outcome, and Need. RESULTS. The need for orthodontic treatment ranged from 37.4 to 48.9% in 10 counties of Lithuania. The study demonstrated that the need of orthodontic treatment significantly depended on age and to some extent on gender of the schoolchildren examined. This study has shown reduction in the need for orthodontic treatment from 49.9% in the late mixed dentition stage to 33.9% in the permanent dentition stage. CONCLUSIONS. The need for orthodontic treatment is high in Lithuania: almost half of 10-11-year-old and every third of 14-15-year-old schoolchildren need orthodontic treatment.

The repositioning Nance appliance: a fixed functional appliance and case report

Functional appliances are primarily orthopaedic tools used to influence the facial skeleton in a growing child. These appliances may be fixed or removable. A fixed functional appliance referred to as the Repositioning Nance Appliance (RNA) was developed and a case report is presented. The RNA is a fixed functional appliance consisting of bands on the upper first molars joined together with a 0.036-inch stainless steel wire that is bent around the anterior contour of the palate. Just lingual to the upper incisors the wire is complemented with an acrylic Nance button, which is modified with a downward and backward incline projection. The labial aspect of this projection is smooth and when the lower incisors come into contact with it, they are directed into an edge-to-edge relation with the upper incisors, brought about by forward positioning of the mandible. This has the net effect of relocating the mandible into a Class I relation. A 14-year-old boy in his late mixed dentition stage of dental development presented with mild crowding, a horizontal growth pattern and a skeletal Class II jaw relation caused by an underdevelopment of the mandible. Treatment was initiated using the RNA and continued for a period of 18 months. This was followed by full fixed appliances for another 12 months and resulted in Class I skeletal and dental relations, a reduced overjet and an improved facial profile. The RNA, if applied correctly is a simple fixed functional appliance that can be used with confidence, comfort and economy to both the patient and orthodontic practitioner.

Retrospective Analysis of Casts to Assess Cervical Headgear Treatment in the Presence of Vertical Growth Pattern

Does molar distalization as effected by cervical headgear increase the vertical dimension of occlusion in patients with vertical growth pattern? A sample of 86 patients with neutral and vertical growth pattern in the late mixed dentition stage underwent headgear treatment. Their initial and intermediary casts were retrospectively analyzed for occlusal relationships at the maxillary first molars and degrees of overjet and overbite. The only cases included were those in which headgear treatment was carried on for at least 6 months, achieving a minimum distalization of 4 mm. The intermediary casts were fabricated after headgear treatment had been completed and prior to the initiation of multiband treatment. Patients were divided into three groups (N, V1 and V2) according to the degrees of vertical growth pattern, which were determined based on y-axis angle values. Grouped by degrees of vertical growth, the data revealed occlusal relationship changes of 6-8 mm and overjet reductions of 0.6-1.2 mm. The overbite changes were unexpectedly small (0-0.04 mm). Grouped by degrees of overbite, the data revealed that headgear treatment increased the vertical dimension of occlusion in deep-bite patients (>4 mm), while giving rise to decreases in patients with overbites of <3 mm.

The positional changes of hyoid bone in children.

The purpose of this study was to investigate the developmental changes of the hyoid bone position in children from deciduous dentition to early permanent dentition. There was no sexual dimorphism in hyoid bone positions. The growth of the structures around the hyoid bone began to decline from late mixed dentition stage. During growth, Go-H was almost equal to C3-H and the hyoid bone was located near and above the line that connected C3 and Me.

Overbite correction and sagittal changes: late mixed-dentition treatment effects

Abstract This study involved the assessment of preand post-treatment lateral cephalograms from 182 late mixed-dentition patients with Class I and Class II malocclusions, with or without crowding, selected before treatment commenced. It was designed specifically to determine whether antero-posterior mandibular dento-alveolar and skeletal changes occurring with growth and one particular late mixed-dentition treatment approach are influenced in any way by the required amount of incisal overbite correction to be achieved with treatment. Significantly greater forward movements were found at both point B and pogonion in non-headgear patients in whom very deep overbites had been reduced, when compared with patients with less required incisal overbite reduction. This finding would seem to have provided further quantitative evidence to support the concept of unlocking of dento-alveolar structures with early reduction of very deep incisal overbites in appropriate patients. The suggestion was therefore made that the bite-opening in such deep-bite patients should be undertaken at least as early as this late mixed-dentition stage in order to provide an improved environment for the mandibular dento-alveolus as the mandible itself moves forward with normal growth.

A strategy for nonextraction class II treatment

Class II nonextraction treatment, which commonly includes distal movement of the maxillary molars to correct the molar relationship, most often can be successful when treatment is started in the late-mixed dentition stage of development. At least two factors contribute to this success. One is that the molars can be distalized routinely at this age. The second is that the “E” space is available and can be used either to help correct the molar relationship or to resolve any crowding that may exist. This article describes and illustrates the treatment of a late mixed-dentition patient with this type of Class II nonextraction treatment that includes distal movement of the maxillary molars with a 100 g NiTi coil system and the maintenance of the “E” space with a lip bumper.

Two phase treatment of a severe Class II, Division I malocclusion

From the Uniw;rsity of Tennessee, Department of Graduate Orthodontics. Presented at the May 1994 Meeting of the American Association of Orthodontists, Orlando, Fla. Associate Professor bOrthodontic Resident CProfessor Am J Orthod Dentofac Orthop 1996;109:461-5. Copyright © 1996 by the American Association of Orthodontists. 0889-5406/96/$5.(10 + 0 814/60634 sors were protrusive, and a deep mentolabial sulcus was apparent. Intraoral: The patient was in the late mixed dentition stage (Fig. 2). A Class II, Division 1 malocclusion was noted with 10 mm overjet and little overbite. Generalized maxillary spacing was present with a 3 mm midline diastema. A midline discrepancy was also present. The maxillary labial frenum inserted into the incisive papilla° Minor irregularity was present in the mandibular incisor segment. Functional assessment: A 2 mm centric relation/centric occlusion (CR/CO) discrepancy was present. No signs or symptoms of temporomandibular disfunction were seen, and the patient had a full range of mandibular motion. The patient demonstrated a tongue thrust swallowing pattern.