Exploration of effect of Odanacatib on inhibiting orthodontic recurrence in rats and on CatK and IGF-1 mRNA.

OBJECTIVE: This study aimed to investigate the inhibitory effect of Odanacatib on orthodontic recurrence in rats. MATERIALS AND METHODS: Forty rats were selected to establish a planting anchorage molar movement model, and 50 g of force was used for the mesial movement of the right maxillary first molar. Forty rats were randomly divided into the observation group (n=20) and control group (n=20). Odanacatib (60 µl, 1.25 µM) was locally injected into the mucoperiosteum around the right maxillary first molar of rats in the experimental group, and an equal amount of normal saline was injected into rats in the control group. A Vernier caliper was used for measuring the recurrence movement distance and recurrence rate of rats, Micro-CT for scanning the bone mineral density (BMD) and bone volume fraction (BVF) of the alveolar bone, TRAP special staining for observing changes in osteoclasts and quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) for detecting the mRNA expressions of cathepsin K (CatK) and insulin-like growth factor 1 (IGF-1) in periodontal tissues. RESULTS: After 3 weeks of modeling, the movement distance of the first molar of rats in the two groups was 1.16±0.19 mm. The molar movement distance and recurrence rate of rats were significantly higher in the control group than those in the observation group (p<0.05). The BMD and BVF of the alveolar bone of rats were markedly lower in the control group than those in the observation group (p<0.05). There was no statistically significant difference in the number of osteoclasts between the observation group (26.15±3.92) and the control group (27.01±2.74) (t=0.882, p=0.383). The CatK mRNA expression of rats was remarkably lower in the observation group than that in the control group (p<0.05). The IGF-1 mRNA expression of rats was significantly higher in the observation group than that in the control group (p<0.05). CONCLUSIONS: By promoting the IGF-1 mRNA expression and increasing the BMD and BVF of the alveolar bone, Odanacatib inhibits orthodontic recurrence and has no effect on osteoclast activity.

Evaluation of Skeletal and Dental Effects of Lower Lingual Arches.

OBJECTIVE: A lower lingual arch is usually recommended as a holding device to maintain arch length and to prevent mesial migration of the mandibular first molars. Despite its widespread use, comparatively little is known about the effects of a lower lingual holding arch on preservation of lower arch dimensions and tooth position and the impact of the device on mandibular growth. The aim of this study is to evaluate the skeletal and dental effects of the lower lingual holding arch with regard to arch dimension, positions of mandibular molars and incisors, and usual mandibular growth. STUDY DESIGN: Thirty-four children (18 males and 16 females) who needed space maintainers were included in the present study. The patients were divided into two groups according to whether they were missing second primary molars on one or both sides. Group I comprised 16 children (8 males and 8 females, average age 8.8 ± 0.9 years) with a missing second primary molar on one side; Group II comprised 18 children (10 males and 8 females, average age 8 ± 0.7 years) with extractions on both sides. Lateral cephalograms, dental pantomograms, and study casts of the patients were taken at the beginning and the end of the study period. Average treatment time was 20.4 ± 4 months. RESULTS: Lower incisors moved forward and Incisor Mandibular Plane Angle (IMPA°) increased in both treatment groups. Statistically significant differences between the groups were found when comparing pre-treatment and post-treatment arch dimension and position of mandibular molars. Results were better for lingual arches with extraction on one side than with extraction on both sides Conclusions: A lingual arch seems to be an effective tool for maintaining arch length, and was not found to impair mandibular growth.

A finite element analysis of the optimal bending angles in a running loop for mesial translation of a mandibular molar using indirect skeletal anchorage.

OBJECTIVES: To estimate the optimal bending angles in the running loop for mesial translation of a mandibular second molar using indirect skeletal anchorage and to clarify the mechanics of tipping and rotating the molar. METHODS: A three-dimensional finite element model was developed for predicting tooth movement, and a mechanical model based on the beam theory was constructed for clarifying the force systems. RESULTS: When using a running loop without bends, the molar tipped mesially 14.4° and lingually 0.6°, rotated counterclockwise 4.1°, and the incisors retracted 0.02 mm and intruded 0.05 mm. These angles were about the same as those estimated by the beam theory. When the amount of tip back and toe-in angles was 11.0°, mesial translation of the molar was achieved, and incisors retracted 0.10 mm and intruded 0.30 mm. CONCLUSIONS: Mesial translation of a mandibular second molar without any significant movement of anterior teeth was achieved during protraction by controlling the tip back and toe-in angles and enhancing anterior anchorage with the combined use of a running loop and indirect skeletal anchorage.

Skeletally anchored mesialization of molars using digitized casts and two surface-matching approaches : Analysis of treatment effects.

PURPOSE: To (1) quantify the three-dimensional treatment effect of a Mesialslider appliance using superimposed digital models, (2) to evaluate anchorage loss (measured by incisor displacement), and (3) to assess agreement between two different matching approaches, i.e., control point (CP)-based and iterative closest point (ICP) matching. METHODS: In a retrospective study, the effects of a skeletally anchored uni- and bilateral mesialization appliance (Mesialslider) as well as simultaneous mesialization and distalization appliance (Mesio-Distalslider) were evaluated in 48 subjects (aged 11-53 years). Pre- and posttreatment casts were digitized and superimposed with two different approaches, i.e., using ten manually selected control points located at the anterior palate and by means of an automated ICP-matching approach using a standardized palatal reference area. The treatment effects were evaluated using control points on the maxillary central incisors and maxillary molar teeth, and the methods were compared through the application of linear regression analyses and computation of alignment errors. RESULTS: Average upper molar mesialization was 6.3 ± 2.6 mm. Anchorage loss, designated as the mean amount of upper incisor displacement, was less than 0.5 mm in all dimensions investigated. Using the measurement method sufficient registration was possible using both approaches and corresponding tooth movements were significantly correlated (p < 0.01). CONCLUSIONS: Accurate measurements of tooth displacement can be performed using both CP- and ICP-based matching approaches. Within the limits of performing a retrospective study, a premolar width of molar mesialization appeared possible without clinically relevant anchorage loss.

Prevalence of proximal contact loss between implant-supported fixed prostheses and adjacent natural teeth and its associated factors: a 7-year prospective study.

OBJECTIVES: The aim was to analyze the prevalence rate of proximal contact loss (PCL) between implant-fixed prostheses (IFPs) and adjacent teeth and investigate the associated factors. MATERIAL AND METHODS: One hundred fifty participants were recruited for this prospective study from January 2009 to December 2014. Two hundred thirty-four IFPs supported by 384 implants for the posterior region were followed up until June 2016. The contact tightness had been recorded using aluminum strips of different thicknesses with a regular interval after delivery. Proximal contact was considered as lost if the contact tightness was over 50 µm, and statistical analyses were performed to estimate the prevalence rate of PCL and its influential factors. RESULTS: Among the total 299 proximal contacts of 234 IFPs, 179 were observed as a PCL (59.9%). Bone level and root configuration of the adjacent teeth, the proximal contact position and jaw position of the implant prostheses were statistically significant factors, when analyzed by the cumulative PCL rate using the log-rank test of the Kaplan-Meier method (P < 0.05) According to the Cox proportional hazard regression analysis, the proximal contact position, bone level of adjacent teeth and jaw position were revealed to be statistically significant (P < 0.05). CONCLUSION: PCL should be considered an implant prosthesis complication to which various associated factors could be related. This study revealed that the lower alveolar bone support level of the adjacent teeth, maxillary position of IFPs and mesial site of IFPs were significantly associated with a higher incidence of PCL.

Asymmetric molars' mesial rotation and mesialization in unilateral functional posterior crossbite and implications for interceptive treatment in the mixed dentition.

INTRODUCTION: Symmetric transverse expansion is the main outcome of the early treatment in subjects with unilateral functional posterior crossbite. The aim of this study was to analyse mesial rotation and mesialization of upper first molars as sagittal parameters to be corrected in the treatment of these patients during the mixed dentition. METHODS: Digital dental cast measurements (rotation and mesialization) were performed in a sample of 48 subjects with unilateral posterior crossbite (UPXB; 19 males and 29 females, mean age 10.2 ± 1.2 years) and in a control group of 35 subjects with normal Class I occlusion (17 males and 18 females, mean age 9.9 ± 1.3 years). An independent sample t-test, the Mann-Whitney test, Fisher's exact test, and Pearson correlation were used for statistical comparison. RESULTS: The amount of upper molar rotation was significantly greater in the experimental group when compared with the control group. A clinically significant 'upper molar rotation' (UMR) was present in 66.7 per cent of the subjects with UPXB versus 5.7 per cent of the control group. The UMR group presented also a significant mesialization of upper first molars when compared with the control group. In the experimental group, there was a significant difference between rotation and mesialization in the right and left side and a correlation has been found between these two variables and the amount of Class II molar relationship at the crossbite side. LIMITATIONS: This is an epidemiological case-control study and the discussed effects of an early correction of the asymmetric upper molars' migration are only speculations based on an association relationship. CONCLUSIONS: The findings of this study show an asymmetric upper first molars' migration (rotation and mesialization) in unilateral functional posterior crossbite versus a control group. An early evaluation and correction of the molars' migration during the mixed dentition should be considered in order to obtain a correct inter-occlusal sagittal molar relationship, space for an adequate eruption of permanent teeth, and perhaps reduce the need of a following fixed appliance treatment in the permanent dentition.

Evaluación radiográfica del grado y radio de curvatura en conductos mesio vestibulares de primeros molares superiores / Radiographic evaluation of the curvature degree and radius in the mesiobuccal canals of maxillary first molars / Avaliação radiográfica do grau e rádio de curvatura em canais mésio-vestibulares de primeiros molares superiores

Objetivo: Determinar el grado y radio de curvatura y su asociación de los conductos radiculares de las raíces mesiales de molares superiores humanos de población Ecuatoriana. Materiales y métodos: Se examinaron un total de 50 primeros mo-lares superiores humanos extraídos, obtenidos del banco de dientes del Subcentro de salud de Tumbaco Pichincha Ecuador, los criterios de exclusión fueron dientes previamente endodonciados, con presencia de caries, reabsorciones o fracturas ra-diculares. Se tomaron radiografías periapicales con técnica de paralelismo, el grado de curvatura se midió en sentido mesio distal con el método de Schneider 1971, y se obtuvo el radio de las curvaturas con la técnica descrita por Estrela 2008. Los datos obtenidos se analizaron mediante la prueba U de Mann Whitney con nivel de significancia del 5%. Resultados: Se determinó que el ángulo de la curvatura fue 10%, 58% y 32% para bajo, moderado y severo respectivamente, mientras que el radio de la curvatura fue 64%, 34%, y 2% para leve, moderado y severo respectivamente. Existió una diferencia estadís-ticamente significativa entre el ángulo moderado y radio leve de los grupos estudiados (p=0,02) Conclusión: Se determinó que es más frecuente el ángulo de curvatura moderado y radio leve.

Objective: Determining the curvature degree and radius and its root canals association in mesial roots of human maxil-lary molars of Ecuadorian population.Materials and methods: A total of 50 human maxillary first molars extracted were studied which were obtained from the Tumbaco health sub-center's teeth bank, Pichincha Ecuador, facts as teeth with a previous root canal treatment, cavities, root resorptionand fracture were the exclusion criteria. Periapical films withparal-leling technique were taken; the curvature degree was measured mesio-distally with the Schneider 1971 technique and the curvature radius was obtained with the technique described by Estrela 2008. The data collected were analyzed with the Mann Whitney's U Test with significance level of 5%. Results:The curvature angle was determined as 10%, 58% and 32% for low, moderate and severe respectively;and the curvature radius was 64%, 34% and 2% for mild, moderate and severe respectively. Among the groups studied, there was a statistically significant difference between the moderate angle and the mild radius (p=0,02). Conclusion: The study found that the moderate curvature angle and mild radiusare the most frequent.

Objetivo: Determinar o grau e o raio de curvatura e a sua associação dos canais radiculares das raízes mesiais dos molares superiores humanos da população equatoriana. Materiais e métodos: Foram examinados um total de 50 primeiros molares superiores humanos extraídos , obtidos do banco de dentes da Unidade Básica de Saúde localizada em Tumbaco Pichincha no Equador. Os critérios de exclusão foram dentes com endodontia prévia, dentes com presença de lesões de cárie dentária , dentes com reabsorções ou com fraturas radiculares. Foram feitas radiografias periapicais com a técnica do paralelismo, o grau de curvatura foi medido no sentido mesiodistal com o método de Schneider 1971, e foi obtido o raio de curvatura com a técnica descrita por Estrela 2008. Os dados obtidos foram analisados pelo teste U de Mann Whitney com nível de significância de 5%. Resultados: Determinou-se que o ângulo da curva foi de 10%, 58% e 32% para baixo, moderado e severo, respectivamente, enquanto que o raio da curvatura foi de 64%, 34%, e 2% para leve, moderado e severo, respectiv-amente. Houve uma diferença estatisticamente significante entre o ângulo moderado e o raio leve nos grupos de estudo (p = 0,02) Conclusão: determinou-se que o ângulo de curvatura moderado e o raio leve são os mais frequentes.

Tratamiento del escalón mesial funcional patológico en un niño de cinco años de edad / Treatment of the pathological functional mesial step in a male child of five years old

La terapia ortodóncica temprana en la dentición temporal está indicada en los casos donde exista un escalón mesial funcional patológico con el objetivo de prevenir un prognatismo verdadero en la edad adulta. Se presenta un paciente masculino de cinco años de edad con esta maloclusión al que se le aplicó una terapéutica con pistas planas indirectas. Además de la terapia funcional según la filosofía de la rehabilitación neuroclusal, que incluyó psicoterapia, tallados selectivos y control de los hábitos, así como la indicación de una dieta fibrosa, se entrenó a los padres y al niño para realizar la masticación bilateral durante las comidas de forma consciente. Finalmente los resultados evidenciaron un balance favorecedor con la utilización de esta terapéutica para la eliminación del escalón mesial funcional patológico y se logró una armonía morfológica y funcional desde edades tempranas del desarrollo(AU)

Changes in proximal contact tightness between fixed implant prostheses and adjacent teeth: A 1-year prospective study.

STATEMENT OF PROBLEM: No study has evaluated consecutive changes in proximal contact tightness (PCT) between fixed implant prostheses and adjacent teeth after delivery. PURPOSE: The purpose of this clinical study was to investigate consecutive biological changes in PCT between fixed implant prostheses and adjacent teeth after placement. MATERIAL AND METHODS: Eighteen participants who had been treated with a single first molar implant in the mandible were included. Mesial and distal PCT were measured using the custom-made contact pressure system at immediate crown delivery (T0), 3-month follow-up (T1), and 1-year follow-up (T2). The PCT of natural teeth in the mesial direction of the same quadrant was also measured at T2 as a control. Repeated-measures analysis of variance (ANOVA) and 1-way ANOVA were used for statistical analysis. RESULTS: At T0, the PCT between fixed implant prostheses and adjacent teeth was designed deliberately to be higher than the PCT between natural teeth. Using multivariate analyses, the PCT between fixed implant prostheses and adjacent teeth decreased between T0 and T1 (P<.001), while there was no significant difference between T1 and T2 (P=.506). At T2, the distal PCT was tighter than the mesial PCT (P<.001); however, no statistical difference was found in the PCT between the implant-supported restoration and the natural teeth. CONCLUSIONS: PCT decreased significantly at both mesial and distal sites over time. The major changes occurred over the 3-month period after crown delivery.

Sistema biomecânico 3D para verticalização de molares inferiores / 3D biomechanical system for mandibular molars uprighting – a case report

A indicação de verticalização de molares inferiores apresenta-se frequente na clínica ortodôntica, principalmente em pacientes com necessidades reabilitadoras. Várias são as possibilidades mecânicas ortodônticas para gerar o momento de força necessário para a verticalização de molares. Contudo, para evitar possíveis efeitos colaterais indesejáveis, deve-se analisar a severidade da impacção, a facilidade de acesso à superfície coronária na decisão de abertura ou fechamento do espaço protético, a necessidade de intrusão, a simplicidade da técnica e sua efetividade. Neste caso clínico, a correta conduta ortodôntica, por meio da biomecânica 3D de verticalização do segundo molar inferior esquerdo, possibilitou a correção rápida da angulação (quatro meses), e a readequação de todo o periodonto de sustentação, sem o surgimento de reabsorções radiculares (custo biológico)...

Uprighting lower molars is a common situation in orthodontics, mainly in patients with rehabilitation needs. There are many mechanical possibilities in orthodontics to generate the necessary moment of force to upright molars. However, to avoid possible undesirable side effects, one must consider the severity of the impaction, the right choice to access the coronary surface when deciding to opening or closing the prosthetic space, the need for intrusion, the simplicity of the technique and its effectiveness. This clinical case reports a correct way to upright mandibular molars by 3D biomechanical system, in a short time of mechanical conduction (four months), with a good periodontal reorganization (alveolar bone mainly), and without biological cost, as root resorption...

Agenesis of maxillary second premolar--diagnosis and clinical management.

Controlling the eruption and development of dentitions is fundamental for a good oral health. The early diagnosis and adequate treatment of occasional developmental disorders are essential to achieve occlusal, functional and esthetic harmony. Abnormality is the term used for classification of alterations and is the most common developmental anomaly in humans. Even though several factors causing tooth malformations have been identified, many are still partially understood, thus requiring a more thorough study. Anyway, the available knowledge provides bases to attempt the early diagnosis of tooth abnormalities, to allow the adoption of preventive and effective therapeutic approaches.

Prevalence of middle mesial canals in mandibular molars after guided troughing under high magnification: an in vivo investigation.

INTRODUCTION: A limited number of in vivo studies have discussed the prevalence of middle mesial canals in root canal systems of mandibular molars. The reported results have varied between 1% and 25%, with no detailed description of the depth and direction of troughing needed to identify such small canal orifices. The objective of the present study was to determine (1) the prevalence of a middle mesial canal before and after troughing by using a standardized troughing technique, (2) the pathway of the middle mesial canal in relation to the mesiobuccal (MB) and mesiolingual (ML) canals, and (3) its correlation with the patient's age. METHODS: Ninety-one mandibular molars from 87 patients were included in this study. The patient's age and tooth number were recorded. After access cavity preparation, a standardized troughing technique was performed between MB and ML canals to search for a middle mesial canal by using a dental operating microscope. If a middle mesial canal was located, it was recorded as separate or as joining the MB or the ML canals. Results were statistically analyzed by using Z test and logistic regression. RESULTS: A middle mesial canal was found in 42 of 91 mandibular molars (46.2%). Six middle mesial canals were located after conventional access preparation (6.6%). The other 36 were located after standardized troughing (39.6%). The results were statistically significant (P < .001). There was a higher tendency to locate the middle mesial canal in second molars (60%) versus first molars (37.5%). Younger patients had a significantly higher incidence of a middle mesial canal (P = .004). CONCLUSIONS: The middle mesial canal was present in 46.2% of mandibular molars. High magnification, troughing, and patient's age appeared to be determining factors in accessing the middle mesial canal.

Factors predisposing to maxillary anchorage loss: a retrospective study of 1403 cases.

Anchorage loss is very disturbing for orthodontists and patients during orthodontic treatment, which usually results in bad treatment effects. Despite the same treatment strategy, different patients show different tendencies toward anchorage loss, which influences the treatment results and should preferably be predicted before the treatment is begun. However, relatively little research has been conducted on which patients are more likely to lose anchorage. The mesial tipping of the first molar marks the onset of anchorage loss, and changes in the angulation of the first molar are closely related to anchorage loss. This cross-sectional study aimed to determine how the mesiodistal angulation of the upper first molars changes during general orthodontic treatment and to identify the individual physiologic factors leading to these changes in a large sample of 1403 patients with malocclusion. The data indicate that the upper first molars tend to be tipped mesially during orthodontic treatment, and this constitutes a type of anchorage loss that orthodontists should consider carefully. Compared to treatment-related factors, patients' physiologic characteristics have a greater influence on changes in the angulation of the upper first molars during orthodontic treatment. The more distally tipped the upper first molars are before treatment, the more they will tip mesially during treatment. Mesial tipping of the upper first molars, and therefore, anchorage loss, is more likely to occur in adolescents, males, patients with class II malocclusion and patients who have undergone maxillary premolar extraction. This finding is of clinical significance to orthodontists who wish to prevent iatrogenic anchorage loss by tipping originally distally tipped upper molars forward, and provides a new perspective on anchorage during orthodontic treatment planning.

Anterior guidance--movement and stability.

Instability of our orthodontic treatment is not uncommon, in particular in the anterior teeth. Given that the mandible is constantly in movement and that the lower and upper teeth regularly meet head-on during normal functioning, one might ask: are the static and normative end of treatment objectives we generally target sufficient to ensure treatment stability?

Método para mesializar segundos molares inferiores em casos de primeiros molares extraídos / Method for lower second molar mesialize in cases extracted first molars

É comum a extração precoce de primeiros molares inferiores, o que leva a uma má oclusão característica, em que o segundo molar inferior se inclina mesialmente e o primeiro pré-molar superior extrui no espaço do primeiro molar inferior ausente. A pergunta mais frequente dos pacientes é se é possível fechar esse espaço. Assim, devemos analisar cada caso, levando em conta fatores de fechamento desse espaço e outros fatores, como a possibilidade de perda de ancoragem anterior, condição óssea na região do primeiro molar extraído e tipo de má oclusão. Descreveremos um dos métodos para a mesialização dos segundos molares inferiores com um arco com alças de Bull ativadas por dobras cadeado e um APM IV, do Dr. Carlos Martins Coelho Filho, para reforçar a ancoragem anteroinferior. Esse método é mais rápido e apresenta menos efeitos colaterais...

Os vários aspectos do tratamento ortodôntico em adultos: relato de um caso clínico de mesialização de molar / Several aspects of orthodontic treatment in adults: report of a case with molar mesialization

A procura por tratamento ortodôntico de pacientes adultos é cada vez maior, porém, o diagnóstico e tratamento desses pacientes devem ser diferenciados. Muitas vezes nos deparamos com espaços edêntulos que podem ser reparados com várias abordagens. Quando se trata da perda de um único dente, as opções de reabilitação do espaço protético são a reposição por implante unitário ou o fechamento de espaço com mesialização ortodôntica de outro dente.

Patient with oligodontia treated with a miniscrew for unilateral mesial movement of the maxillary molars and alignment of an impacted third molar.

This report describes the treatment of a 20-year-old woman with a dental midline deviation and 7 congenitally missing premolars. She had retained a maxillary right deciduous canine and 4 deciduous second molars, and she had an impacted maxillary right third molar. The maxillary right deciduous second molar was extracted, and the space was nearly closed by mesial movement of the maxillary right molars using an edgewise appliance and a miniscrew for absolute anchorage. The miniscrew was removed, and the extraction space of the maxillary right deciduous canine was closed, correcting the dental midline deviation. After the mesial movement of the maxillary right molars, the impacted right third molar was aligned. To prevent root resorption, the retained left deciduous second molars were not aligned by the edgewise appliance. The occlusal contact area and the maximum occlusal force increased over the 2 years of retention. The miniscrew was useful for absolute anchorage for unilateral mesial movement of the maxillary molars and for the creation of eruption space and alignment of the impacted third molar in a patient with oligodontia.

Comparison of arch width, alveolar width and buccolingual inclination of teeth between Class II division 1 malocclusion and Class I occlusion.

OBJECTIVE: To compare the arch width, alveolar width, and buccolingual inclination of maxillary and mandibular posterior teeth between Class II division 1 malocclusion and Class I occlusion. MATERIALS AND METHODS: Forty-five subjects with Class I occlusion and 45 subjects with Class II division 1 malocclusion were selected to measure the maxillary and mandibular arch width and alveolar width of premolars and first molars with digital caliper. Buccolingual inclination of maxillary and mandibular premolars and first molars were measured with a modified universal bevel protractor. RESULTS: All of the posterior teeth in both groups were lingually tilted. The maxillary premolars and first molars were significantly more lingually tilted (P < .05) in Class II division 1 malocclusion than in Class I occlusion. Mandibular first premolars were significantly less lingually tilted in Class II division 1 malocclusion than in Class I occlusion. No significant difference of buccolingual inclination was found in mandibular second premolars and first molars between the two groups. No significant difference in maxillary and mandibular arch width and alveolar width was found between the two groups. CONCLUSIONS: Buccolingual inclination rather than arch width and alveolar width plays an important role in transverse discrepancy of Class II division 1 malocclusion.