[Treatment of class II for growing patients by clear aligners: which protocol?] / Traitement des classes II pour les patients au cours de la croissance par gouttières thermoformées : quel protocole ?

INTRODUCTION: Skeletal class II, frequently associated with retromandibular and overjet > 2 mm, lead to functional and aesthetic damage, that orthodontic treatment has to correct. The aim of this article is to describe a treatment protocol by aligners for class II growing patients according to the value of the class II and the maturity state of cervical vertebrae. MATERIALS AND METHODS: Through clinical cases, this article will present three different therapeutic approaches depending on the growth state. RESULTS: The study of the auxologic potential and determination of the bone age (radiological analysis of the maturation of the cervical vertebrae) will allow to determine the best moment to treat class II and the most appropriate therapeutic attitude according to growing state. DISCUSSION: This study before treatment is essential to adapt an individualized clinical protocol to each patient. In this way, aligners are devices that respond well to this imperative because they are customizable in view of the strategy and the treatment plan considered by the practitioner. We must keep in mind, however, that with any therapy, it is essential to ensure good patient compliance.

Relationship between the curve of Spee and craniofacial variables: A regression analysis.

INTRODUCTION: The aim of this regression analysis was to identify the determining factors, which impact the curve of Spee during its genesis, its therapeutic reconstruction, and its stability, within a continuously evolving craniofacial morphology throughout life. MATERIAL AND METHODS: We selected a total of 107 patients, according to the inclusion criteria. A morphological and functional clinical examination was performed for each patient: plaster models, tracing of the curve of Spee, crowding, Angle's classification, overjet and overbite were thus recorded. Then, we made a cephalometric analysis based on the standardized lateral cephalograms. In the sagittal dimension, we measured the values of angles ANB, SNA, SNB, SND, I/i; and the following distances: AoBo, I/NA, i/NB, SE and SL. In the vertical dimension, we measured the values of angles FMA, GoGn/SN, the occlusal plane, and the following distances: SAr, ArD, Ar/Con, Con/Gn, GoPo, HFP, HFA and IF. The statistical analysis was performed using the SPSS software with a significance level of 0.05. RESULTS: Our sample including 107 subjects was composed of 77 female patients (71.3%) and 30 male patients (27.8%) 7 hypodivergent patients (6.5%), 56 hyperdivergent patients (52.3%) and 44 normodivergent patients (41.1%). Patients' mean age was 19.35±5.95 years. The hypodivergent patients presented more pronounced curves of Spee compared to the normodivergent and the hyperdivergent populations; patients in skeletal Class I presented less pronounced curves of Spee compared to patients in skeletal Class II and Class III. These differences were non significant (P>0.05). The curve of Spee was positively and moderately correlated with Angle's classification, overjet, overbite, sellion-articulare distance, and breathing type (P<0.05). We found no correlation between age, gender and the other parameters included in the study with the curve of Spee (P>0.05). Seventy five percent (75%) of the hyperdivergent patients with an oral breathing presented an overbite of 3mm, which is quite excessive given the characteristics often admitted for this typology; this parameter could explain the overbite observed in the hyperdivergent population included in this study. For the multivariate analysis, the overbite and the sellion-articulare distance remained independently related to the curve of Spee according to the breathing type, Angle's classification, and overjet. This regression model explains 21.4% of the changes in the curve of Spee.

Dentoskeletal and soft tissue changes in class II subdivision treatment with asymmetric extraction protocols.

BACKGROUND: This study cephalometrically compared the dentoskeletal and soft tissue changes consequent to one and three-premolar extraction protocols of class II subdivision malocclusion treatment. METHODS: A sample of 126 lateral cephalometric radiographs from 63 patients was selected and divided into two groups. Group 1 consisted of 31 type 1 class II subdivision malocclusion patients treated with asymmetric extractions of two maxillary premolars and one mandibular premolar on the class I side, with an initial mean age of 13.58 years. Group 2 consisted of 32 type 2 class II subdivision malocclusion patients treated with asymmetric extraction of one maxillary first premolar on the class II side, with an initial mean age of 13.98 years. t test was used for intergroup comparison at the pre- and posttreatment stages and to compare the treatment changes. RESULTS: Group 1 had greater maxillomandibular sagittal discrepancy reduction and greater maxillary first molar extrusion. Group 2 had mandibular incisor labial inclination and protrusion, and group 1 had mandibular incisor lingual inclination and retraction. Maxillary molar asymmetry increased in group 2, while mandibular molar asymmetry increased in group 1. CONCLUSIONS: The treatment changes produced by these two class II subdivision protocols are different to adequately satisfy the different needs for types 1 and 2 class II subdivision malocclusions.

The Influence of Class II Division 2 Malocclusions on the Harmony of the Human Face Profile.

BACKGROUND Persons with class II division 2 malocclusion are characterized by a very specific dento-skeletal and soft-tissue profile (a profile in which a protruding nose and chin, retruding lips, concave and shortened lower third of the face, and gummy smile are dominant), which is the opposite of the currently modern profiles (convex profile of protruding lips and small chin). The aim of this research was to determine the differences in parameters of harmonies of facial profiles between persons with class II division 2 malocclusions and class I, and to establish the significance of those differences. MATERIAL AND METHODS For this study, 50 patients with class II division 2 malocclusions and 50 patients with class I were selected; profile photos were recorded and a photometric analysis was done: a type of profile according to Schwarz, the shape of a nose, the prominence of chin, biometrical field, the position of lips in relation to the tangent Sn-Pg, S-line (Steiner), E-line (Riketts) and a facial angle according to Arnett. RESULTS The significant differences in profiles of persons with class II division 2 compared to class I were: position and prominence of the chin, the position of the lower and upper lip in relation to the S-line, and smaller value of a facial angle in relation to persons with class I. CONCLUSIONS The differences seen in skeletal profiles were not associated with significant differences in the profiled facial contours of the examined groups. The compensatory role of the fullness of soft tissues of the lips is probably the reason why there were not significant deviations in all the examined parameters.

A Comparison of Three Orthodontic Treatment Indices with Regard to Angle Classification.

OBJECTIVES: To calculate the agreement between the Dental Aesthetic Index (DAI) and the Index of Complexity, Outcome and Need (ICON) in assessing orthodontic treatment need and to determine correlations between the Peer Assessment Rating (PAR) and DAI and ICON scores according to Angle classification among patients referred for orthodontic evaluation. STUDY DESIGN: This study included 457 randomly selected patients between 9 to 17 years of age. Patients were divided into four groups according to Angle classification [Class I (n=154), Class II division 1(Class II/1) (n=155), Class II division 2(Class II/2) (n=52) and Class III (n=96)]. Relationships between PAR scores and ICON and DAI scores were evaluated with the Spearman correlation test. Unweighted kappa statistics were used to analyse agreement between the ICON and DAI on the need for treatment, according to Angle classification. RESULTS: Class I malocclusions scored significantly lower than other Angle classifications in all indices. Both the ICON and DAI showed significant positive correlations with the PAR in the general study population. For Class II/2 patients, no correlation was found between PAR and DAI scores. There was significant agreement between the ICON and DAI on treatment need among Class I, Class II/1 and Class II/2 patients however, no agreement was found for Class III malocclusions. CONCLUSIONS: The ICON, DAI and PAR produce similar results and can be used interchangeably for the general orthodontic patient population. However, based on Angle classification, prominent differences exist in scoring certain occlusal features.

Stability of class II subdivision malocclusion treatment with 3 and 4 premolar extractions.

BACKGROUND: The purpose of this study was to compare the occlusal stability of class II subdivision malocclusion treatment with 3 and 4 first premolar extractions. A sample of 156 dental casts from 52 patients with class II subdivision malocclusion was divided into two groups according to the extraction protocol. Group 1 comprised 24 patients treated with 3 premolar extractions and group 2 included 28 patients treated with 4 premolar extractions. METHODS: Peer assessment rating (PAR) indexes were measured on the dental casts obtained before (T1) and after treatment (T2) and at a mean of 6.9 years after the end of treatment (T3). The groups were matching regarding sex distribution, pretreatment, posttreatment and long-term posttreatment ages, and treatment and long-term posttreatment times. They were also comparable concerning the initial malocclusion severity and the occlusal results at the end of treatment. Stability evaluation was calculated by subtracting the posttreatment from the long-term posttreatment index values (T3 - T2). T tests were used to compare the amount and percentage of long-term posttreatment changes. RESULTS: There were no intergroup differences regarding the amount and percentage of long-term posttreatment changes. CONCLUSION: Treatment of class II subdivision malocclusion with 3 and 4 premolar extractions have a similar long-term posttreatment occlusal stability.

Lateral cephalometric diagnosis of asymmetry in Angle Class II subdivision compared to Class I and II.

INTRODUCTION: Lateral cephalometric radiographs are traditionally required for orthodontic treatment, yet rarely used to assess asymmetries. OBJECTIVE: The objective of the present study was to use lateral cephalometric radiographs to identify existing skeletal and dentoalveolar morphological alterations in Class II subdivision and to compare them with the existing morphology in Class I and II relationship. MATERIAL AND METHODS: Ninety initial lateral cephalometric radiographs of male and female Brazilian children aged between 12 to 15 years old were randomly and proportionally divided into three groups: Group 1 (Class I), Group 2 (Class II) and Group 3 (Class II subdivision). Analysis of lateral cephalometric radiographs included angular measurements, horizontal linear measurements and two indexes of asymmetry that were prepared for this study. RESULTS: In accordance with an Index of Dental Asymmetry (IDA), greater mandibular dental asymmetry was identified in Group 3. An Index of Mandibular Asymmetry (IMA) revealed less skeletal and dental mandibular asymmetry in Group 2, greater skeletal mandibular asymmetry in Group 1, and greater mandibular dental asymmetry in Group 3. CONCLUSION: Both IDA and IMA revealed greater mandibular dental asymmetry for Group 3 in comparison to Groups 1 and 2. These results are in accordance with those found by other diagnostic methods, showing that lateral cephalometric radiography is an acceptable method to identify existing skeletal and dentoalveolar morphological alterations in malocclusions.

Assessment of dental arches in patients with Class II division 1 and division 2 malocclusions using 3D digital models in a Syrian sample.

AIM: (1) to evaluate the applicability of using 3D digital models in the assessment of Class II Division 1 (Cl II-1) and Class II Division 2 (Cl II-2) malocclusion in a Syrian sample, (2) to detect any significant differences between the two groups in tooth and arch widths, anterior (ABR) and overall Bolton ratios, PAR Index, and (3) to detect any gender differences in these variables. DESIGN AND SETTING: observational, cross-sectional study for descriptive and analytical purposes at the Orthodontic Dept., University of Al-Baath Hamah Dental School, Hamah, Syria. PARTICIPANTS: A disproportionate multi-stratified random sampling was employed to select 36 Cl II-1 and 36 Cl II-2 patients (female-to-male ratio was 1:1 in each group). 3D digital models (O3DM) with a dedicated programme were used to measure dental arch variables. RESULTS: Significant differences were observed between the two groups in the mesiodistal widths of some teeth but not in the dental arch widths. The prevalence of 'discrepancy cases' in Anterior Bolton Ratios (ABRs) was 33.33% and 41.67% in Cl II1 and Cl II2 groups, respectively. The mean PAR Index score was 25.36 and 20.82 for Cl II1 and Cl II2 groups, respectively (p=0.009). CONCLUSIONS: (1) 3D digital models enabled fast, accurate and reliable measurements of dental arch characteristics in patients with Class II malocclusion. (2) Insignificant differences between Cl II1 and Cl II2 patients were observed regarding Bolton's ratios and transverse arch measurements. (3) Sexual dimorphism was observed in mesiodistal tooth widths and in dental arch widths, but not in Bolton's ratios and PAR Index scores.

Lateral cephalometric diagnosis of asymmetry in Angle Class II subdivision compared to Class I and II

INTRODUCTION: Lateral cephalometric radiographs are traditionally required for orthodontic treatment, yet rarely used to assess asymmetries. OBJECTIVE: The objective of the present study was to use lateral cephalometric radiographs to identify existing skeletal and dentoalveolar morphological alterations in Class II subdivision and to compare them with the existing morphology in Class I and II relationship. MATERIAL AND METHODS: Ninety initial lateral cephalometric radiographs of male and female Brazilian children aged between 12 to 15 years old were randomly and proportionally divided into three groups: Group 1 (Class I), Group 2 (Class II) and Group 3 (Class II subdivision). Analysis of lateral cephalometric radiographs included angular measurements, horizontal linear measurements and two indexes of asymmetry that were prepared for this study. RESULTS: In accordance with an Index of Dental Asymmetry (IDA), greater mandibular dental asymmetry was identified in Group 3. An Index of Mandibular Asymmetry (IMA) revealed less skeletal and dental mandibular asymmetry in Group 2, greater skeletal mandibular asymmetry in Group 1, and greater mandibular dental asymmetry in Group 3. CONCLUSION: Both IDA and IMA revealed greater mandibular dental asymmetry for Group 3 in comparison to Groups 1 and 2. These results are in accordance with those found by other diagnostic methods, showing that lateral cephalometric radiography is an acceptable method to identify existing skeletal and dentoalveolar morphological alterations in malocclusions. .

INTRODUÇÃO: as telerradiografias laterais são tradicionalmente solicitadas para planejamento ortodôntico, mas raramente utilizadas para avaliar assimetrias. OBJETIVO: o objetivo do presente estudo foi utilizar as telerradiografias laterais para identificar as alterações morfológicas esqueléticas e dentoalveolares existentes na má oclusão de Classe II subdivisão e compará-las com a morfologia existente nas más oclusões de Classe I e II. MÉTODOS: noventa telerradiografias laterais iniciais de adolescentes brasileiros de ambos os sexos, com idade cronológica entre 12 e 15 anos, foram divididas em três grupos randomizados e proporcionais: Grupo 1 (Classe I), Grupo 2 (Classe II) e Grupo 3 (Classe II subdivisão). A análise das telerradiografias laterais envolveu mensurações angulares, mensurações lineares horizontais e dois índices de assimetria, estipulados para o presente estudo. RESULTADOS: foi identificada, de acordo com o Índice de assimetria dentária (IAD), uma maior assimetria dentária inferior no Grupo 3. O Índice de assimetria mandibular (IAM) revelou menor assimetria esquelética e dentária no Grupo 2, maior assimetria esquelética no Grupo 1 e maior assimetria dentária inferior no Grupo 3. CONCLUSÃO: o IAD e o IAM mostraram maior assimetria dentária inferior no Grupo 3 do que nos Grupos 1 e 2. Esses resultados estão de acordo com os encontrados em outros métodos de diagnóstico, indicando que a telerradiografia lateral é um método aceitável para avaliar alterações morfológicas esqueléticas e dentoalveolares nas más oclusões. .

Permanent mandibular canine(s) impaction: expansion of our understanding.

INTRODUCTION: Eruption disturbances, tooth size and specific malocclusions are known to be genetically influenced. The clinical association between these traits may indicate common genetic controls. OBJECTIVES: A cross-sectional clinical study was designed to test the null hypothesis that the maximum mesiodistal crown diameter (MMD) of maxillary and mandibular central and lateral incisors and the prevalence of various classes of incisor relationships (Class I, II/1, II/2 and III) do not differ between the subjects with and without permanent mandibular canine(s) impaction. METHODS: Dental models of 43 subjects diagnosed with mandibular canine(s) impaction (Impaction Group - IG) were compared with those of 86 subjects of a control reference sample (Control Group - CG). Independent t-test and chi-square tests were used to determine the association between mandibular canine(s) impaction and the MMD of the incisors and the incisor relationship, respectively. The likelihood of various incisor relationships between the IG and CG were evaluated according to odds ratios. RESULTS: A fourfold increase (p < 0.0001) in the overall frequency of Class II/2 incisor relationship was observed in the IG when compared to controls. CONCLUSIONS: The null hypothesis was rejected. Subjects with mandibular canine(s) impaction appeared to be characterised with wider incisors and a remarkably high rate of Class II/2 malocclusion. This information assists the understanding of genetically controlled dental anomalies, which are likely to coexist with mandibular canine(s) impaction.

Classification and treatment of Class II subdivision malocclusions.

INTRODUCTION: Patients with Class II subdivision malocclusions are a challenge for clinicians because reestablishing symmetry in 1 arch or both arches is often a treatment goal. In patients with mandibular skeletal asymmetry, surgery is often a treatment option. However, patients may be unwilling to undergo surgery, and other options might have to be considered. The aim of this study was to evaluate the etiologies and outcomes of Class II subdivision patients treated at the University of Washington graduate orthodontic clinic in Seattle from 1995 through 2011. METHODS: A search of patients treated between 1995 and 2011 resulted in the identification of 110 consecutively treated Class II subdivision subjects with complete records. Ninety-eight subjects could be classified into 1 of 3 groups, based on midline position and dental or skeletal etiology. Initial and final models were used to measure the peer assessment rating scores, midlines, overjet, overbite, and molar positions. Initial and final cephalograms were traced and measured. Charts were reviewed for information regarding treatment. RESULTS: Twenty-five percent of the 98 subjects had their maxillary and mandibular midlines coincident with the facial midline; their asymmetries were due to a maxillary posterior dental asymmetry. Another 15% had maxillary midlines deviated from their facial midlines, caused by maxillary anterior and posterior dental asymmetry. About 50% of the subjects had mandibular midlines that were not coincident with their facial midlines, and most of them exhibited some degree of mandibular skeletal asymmetry. Over the past 15 years, treatment strategies used at the University of Washington indicated trends toward less surgery, fewer extractions, less use of headgear, and more reliance on fixed functional appliances. Ideal correction of midlines was not always achieved, especially in patients with mandibular skeletal asymmetry, with undercorrection occurring more commonly than overcorrection. Final peer assessment rating scores were comparable, regardless of the origin of the asymmetry or the extractions status. Mandibular incisor proclination was increased when fixed functional appliances were used, as well as when a Class I molar relationship was the target for the Class II side. CONCLUSIONS: Class II subdivision malocclusions were grouped into 3 main categories; the largest category was mandibular asymmetry. Interesting trends were noted with regard to treatment strategies, midline and molar corrections, and mandibular incisor proclination.

Relationship between crown-root angulation (collum angle) of maxillary central incisors in Class II, division 2 malocclusion and lower lip line.

AIM: The present study aimed to measure the magnitude of the collum angle (crown-root angulation) of maxillary central incisors present in Class II, division 2 malocclusion and to relate the changes in its magnitude with variations in the lower lip line. METHODS: A set of 120 conventional lateral cephalograms were selected and divided into three groups of 40 each based on the type of malocclusion presented: Class II, division 2 (group 1); Class II, division 1 (group 2); and Class I (group 3). The collum angle of the maxillary central incisor was measured, and the lower lip line was recorded. RESULTS: Analysis of variance (ANOVA) revealed that the mean collum angle was statistically significantly different in the three groups. The mean collum angle was greatest in Class II, division 2 malocclusion (group 1). The mean collum angles were 3.24 ± 4.69 degrees, 0.95 ± 1.06 degrees, and 1.05 ± 1.50 degrees in groups 1, 2, and 3 respectively. In χ ² test comparison of the location of the lower lip line (incisal, middle, or apical third of the central incisor) among the three groups, the lower lip line was found to contact the middle third of the central incisor most frequently in Class II, division 2 malocclusion. ANOVA followed by Tukey honestly significant difference (HSD) test showed that the mean collum angle is significantly increased when the lower lip is in the middle third (P < .05) of the central incisor. CONCLUSION: Variations in magnitude of the collum angle with the change in the lower lip line suggest a probable etiologic role of the lower lip line in the development of the collum angle.

Magnetic resonance imaging-verified temporomandibular joint disk displacement in relation to sagittal and vertical jaw deformities.

This retrospective study was designed to analyze the relationships between temporomandibular joint (TMJ) disk displacement and skeletal deformities in orthodontic patients. Subjects consisted of 460 adult patients. Before treatment, lateral cephalograms and TMJ magnetic resonance imaging (MRI) were recorded. Subjects were divided into six groups based on TMJ MRI according to increasing severity of TMJ disk displacement, in the following order: bilateral normal TMJs, unilateral disk displacement with reduction (DDR) and contralateral normal, bilateral DDR, unilateral disk displacement without reduction (DDNR) and contralateral normal, unilateral DDR and contralateral DDNR, and bilateral DDNR. Subjects were subdivided sagittally into skeletal Class I, II, and III deformities based on the ANB (point A, nasion, point B) angle and subdivided vertically into hypodivergent, normodivergent, and hyperdivergent deformities based on the facial height ratio. Linear trends between severity of TMJ disk displacement and sagittal or vertical deformities were analyzed by Cochran-Mantel-Haenszel test. The severity of TMJ disk displacement increased as the sagittal skeletal classification changed from skeletal Class III to skeletal Class II and the vertical skeletal classification changed from hypodivergent to hyperdivergent. There were no significant differences in the linear trend of TMJ disk displacement severity between the sexes according to the skeletal deformities. This study suggests that subjects with skeletal Class II and/or hyperdivergent deformities have a high possibility of severe TMJ disk displacement, regardless of sex.

Soft tissue effects of Twin Block and Herbst appliances in patients with Class II division 1 mandibular retrognathy.

The aim of this study was to evaluate and compare the changes in soft tissue profile related to treatment with Twin Block and Herbst appliances. Sixty Class II, division 1, mandibular retrognathic patients were divided into three groups. Forty patients were randomly allocated to one of two functional appliance treatment groups. The first group comprised 11 girls and 9 boys (mean age= 12.74 ± 1.43 years) treated with the Herbst appliance. The second group comprised 10 girls and 10 boys (mean age = 13.0 ± 1.32 years) who received treatment with Twin Block appliance. The untreated control group included 9 girls and 11 boys with a mean age of 12.17 ± 1.47 years. Mean treatment time was 15.81 ± 5.96 and 16.20 ± 7.54 months for Herbst and Twin Block groups, respectively. The observation period of the control group was 15.58 ± 3.13 months. Pre-treatment (T0) and post-treatment (T1) cephalograms were used to evaluate skeletal, dentoalveolar, and especially soft tissue changes. The groups were compared at T0 and T1 using analysis of variance, and treatment/observation differences (T1 - T0) were evaluated with paired samples t-test at P < 0.05 level. Soft tissue convexity, H angle, and mentolabial angle decreased in both treatment groups compared to control. Statistically significant treatment changes were found for mandibular soft tissue measurements in Twin Block group and to a lesser extend in Herbst group. Both appliances reduced the soft tissue profile convexity when the nose is not taken into consideration. Greater advancement of mandibular soft tissues was observed in Twin Block group.

Tratamiento de la clase II en dentición permanente con la técnica CSW / Class II treatment in permanent dentition with the CSW technique

En los artículos anteriores trabajamos: 1- manejo del perfil de la clase II esquelética con la técnica CSW (Custom-made Straight Wire). Se expuso la importancia del diagnóstico y de la planificación del tratamiento de ortodoncia. 2- En “Tratamiento de la clase II en dentición mixta con la técnica CSW (Custom-made Straight Wire)”analizamos el tratamiento temprano de la clase II. En el presente artículo se analiza el tratamiento de la clase II en dentición permanente, relacionando eltratamiento con el diagnóstico realizado.

Tratamiento de la clase II en dentición permanente con la técnica CSW / Class II treatment in permanent dentition with the CSW technique

En los artículos anteriores trabajamos: 1- manejo del perfil de la clase II esquelética con la técnica CSW (Custom-made Straight Wire). Se expuso la importancia del diagnóstico y de la planificación del tratamiento de ortodoncia. 2- En ôTratamiento de la clase II en dentición mixta con la técnica CSW (Custom-made Straight Wire)öanalizamos el tratamiento temprano de la clase II. En el presente artículo se analiza el tratamiento de la clase II en dentición permanente, relacionando eltratamiento con el diagnóstico realizado.(AU)

Class II malocclusion division 1: a new classification method by cephalometric analysis.

AIM: The purpose of this study was to analyse the craniofacial and dentofacial skeletal characteristics in untreated subjects with Class II, division 1 malocclusion by mandibular retrusion and to identify different types and their prevalence. MATERIALS AND METHODS: In 152 subjects with Class II, division 1 malocclusion by mandibular retrusion, the differences were determined by lateral cephalograms analysis of variance and chi-square test, respectively. P<0.05 was considered significant. Seven types of mandibular retrusion were identified: three pure, dimensional, rotational and positional, and four mixed. RESULTS: All patients showed significant inter-group differences with P between 0.005 and 0.001. The dimensional type was the most common (28.9%) and the rotational-positional type was the rarest (5.9%). The pure dimensional type had the shortest mandibular body; the pure rotational type had larger SN/GoMe and the lowest AOBO; the pure positional type presented the flattest cranial base, high AOBO. In the mixed types, dento-skeletal features changed depending on how the main types assorted. CONCLUSIONS: Identifying the type of mandibular retrusion is important for differential diagnosis in clinical practice and research.

Alternativas para la resolución de deckbiss: técnica convencional y técnica de baja fricción / Alternatives for the resolution of deckbiss: conventional technique and low friction technique

La maloclusión de mordida cubierta o Deckbiss, según la nomenclatura europea (también denominada clase II, 2º división, siguiendo la clasificación de Angle), tiene su origen en dos componentes, uno genético y otro estructural. El segundo, dado por estructuras dentarias, musculares y funcionales características. Estadísticamente, la mayor prevalencia de esta maloclusión se da en individuos originarios del centro de Europa. El signo patognomónico de un deckbiss es la posición recta de los incisivos superiores y la extrusión de sus procesos alveolares. Acompaña también una retrusión alveolar inferior por la posición de la cara palatina de los incisivos superiores que condiciona a los inferiores. Esta traba de como resultado una alteración de la cinemática mandibular. Esta maloclusión presenta una alta incidencia de disfunción del sistema estomatognático. Clínicamente, se pueden observar tres tipos de morfologías. Sin embargo, debido al alto componente de inmigrantes de nuestra sociedad y su mezcla genética, se pueden ver múltiples variaciones morfológicas: una con incisivos superiores rectos y apiñamiento de incisivos inferiores. Una vez resuelto el alineamiento inferior nos queda una relaciónn contactante anterior. Otra con los incisivo superiores rectos y sin apiñamiento inferior. Luego del reposicionamiento de los incisivos superiores y liberada la traba que significa para la mandíbula ese contacto dentario anterior, quedará un overjet moderado. Este necesitará ser reducido. Por último, después de la resolución superior y debido a la posición retruida del proceso alveolar en la zona anterior, queda un gran escalón. Este exige quitar piezas dentarias superiores para disminuir la longitud y el perímetro del arco superior. En este trabajo se presentan dos casos clínicos de pacientes. Uno se realizó con aparatología convencional y el otro con técnica de baja fricción. Se analizaron a la luz de las nuevas técnicas propuestas

Alternativas para la resolución de deckbiss: técnica convencional y técnica de baja fricción / Alternatives for the resolution of deckbiss: conventional technique and low friction technique

La maloclusión de mordida cubierta o Deckbiss, según la nomenclatura europea (también denominada clase II, 2º división, siguiendo la clasificación de Angle), tiene su origen en dos componentes, uno genético y otro estructural. El segundo, dado por estructuras dentarias, musculares y funcionales características. Estadísticamente, la mayor prevalencia de esta maloclusión se da en individuos originarios del centro de Europa. El signo patognomónico de un deckbiss es la posición recta de los incisivos superiores y la extrusión de sus procesos alveolares. Acompaña también una retrusión alveolar inferior por la posición de la cara palatina de los incisivos superiores que condiciona a los inferiores. Esta traba de como resultado una alteración de la cinemática mandibular. Esta maloclusión presenta una alta incidencia de disfunción del sistema estomatognático. Clínicamente, se pueden observar tres tipos de morfologías. Sin embargo, debido al alto componente de inmigrantes de nuestra sociedad y su mezcla genética, se pueden ver múltiples variaciones morfológicas: una con incisivos superiores rectos y apiñamiento de incisivos inferiores. Una vez resuelto el alineamiento inferior nos queda una relaciónn contactante anterior. Otra con los incisivo superiores rectos y sin apiñamiento inferior. Luego del reposicionamiento de los incisivos superiores y liberada la traba que significa para la mandíbula ese contacto dentario anterior, quedará un overjet moderado. Este necesitará ser reducido. Por último, después de la resolución superior y debido a la posición retruida del proceso alveolar en la zona anterior, queda un gran escalón. Este exige quitar piezas dentarias superiores para disminuir la longitud y el perímetro del arco superior. En este trabajo se presentan dos casos clínicos de pacientes. Uno se realizó con aparatología convencional y el otro con técnica de baja fricción. Se analizaron a la luz de las nuevas técnicas propuestas (AU)

Mixed longitudinal evaluation of masticatory performance in children 6 to 17 years of age.

INTRODUCTION: The purposes of this study were to determine (1) how masticatory performance changes with age, (2) whether masticatory performance differs between the sexes, and (3) whether patterns of masticatory performance differ among subjects with various types of malocclusion. METHODS: A total of 450 children and adolescents (244 boys, 206 girls) were assigned to 4 age cohorts (ages 6, 9, 12, and 15 years) and followed for 3 consecutive years. The subjects were selected based on having about equal numbers of boys and girls, and about equal numbers of subjects with normal occlusion and Class I and Class II malocclusions. Masticatory performance was assessed by using the artificial food CutterSil (Heraeus Kulze, South Bend, Ind). The peer assessment rating index was used to quantify the severity of the malocclusions. RESULTS: Median particle size (MPS) decreased significantly from 6 to 17 years of age. There were no statistically significant differences in MPS between the 3 occlusal groups, but there were significant sex differences, with girls having smaller MPS than boys. Multilevel analysis showed greater decreases in MPS between 6 and 9 years, and after 12 years of age, than between 9 and 12 years of age. There were no significant correlations between MPS and the weighted peer assessment rating index. MPS showed significant intercorrelations between measures of MPS obtained at years 1, 2, and 3, with correlations tending to be highest for the oldest age cohort. CONCLUSIONS: Masticatory performance improves with age, and the changes appear to be influenced by the loss of the deciduous teeth during the late mixed dentition phase of dental development. Although there are limited sex differences in masticatory performance among subjects 6 to 17 years of age, mild forms of Class I and Class II malocclusions have little or no effect on masticatory performance.