Assessment of divine proportion in the cranial structure of individuals with Angle Class II malocclusion on lateral cephalograms

INTRODUCTION: The study of the Divine Proportion (Φ = 1.618) began with the Greeks, having as main researchers the mathematician Pythagoras and the sculptor Phidias. In Dentistry, Ricketts (1981-82) was an early to study this issue. OBJECTIVE: This study proposed to evaluate how some cephalometric measures are presented in relation to the Divine Proportion, with the total of 52 proportions, formed by 28 cephalometric landmarks. METHODS: Lateral cephalograms of 40 Class II adults patients aging from 17 to 45 years (13 male and 27 female) were evaluated. The linear distances between the landmarks were measured using Radiocef Studio software. RESULTS: After statistical analysis, the data shown an average of 65,48% in the Divine Proportion, 17,5% in the relation Ans-Op/V1S-DM16 and 97,5% in the relations Na-Me/Na-PoNa e Na-PoNa/Na-Gn. CONCLUSION: Among all cephalometric measurements investigated, the lower facial third and the dental arches showed the smallest percentages of Divine Proportion.

Avaliação cefalométrica da posição do osso hióide em crianças respiradoras bucais

MATERIAL E MÉTODOS: em função das relações anatomofuncionais do osso hióide com o complexo craniofacial, realizou-se avaliação cefalométrica da posição do osso hióide em relação ao padrão respiratório. A amostra consistiu de 53 crianças, gênero feminino, com idades médias de 10 anos, sendo 28 respiradoras nasais e 25, bucais. As medidas cefalométricas horizontais, verticais e angulares foram utilizadas com a finalidade de determinar a posição do osso hióide. Estabeleceu-se uma comparação entre os grupos por meio do teste t de student, bem como correlação de Pearson entre as variáveis. RESULTADOS: Observou-se que não ocorreram diferenças estatísticas significativas para a posição mandibular e posição do osso hióide e o tipo do padrão respiratório. No Triângulo Hióideo, o coeficiente de correlação de 0,40 foi significativo entre AA-ENP (distância entre vértebra atlas e espinha nasal posterior) e C3-H (distância entre a terceira vértebra cervical e osso hióide) demonstrando uma relação positiva entre os limites ósseos do espaço aéreo superior e inferior. Para as medidas cranianas sugeriu-se uma relação entre a posição do osso hióide com a morfologia mandibular. CONCLUSÃO: Os resultados permitiram concluir que o osso hióide mantém uma posição estável, provavelmente, para garantir as proporções corretas das vias aéreas e não depende do padrão respiratório predominante.

Avaliação cefalométrica do espaço aéreo posterior em pacientes com oclusão Classe II submetidos à cirurgia ortognática

OBJETIVO: o avanço maxilomandibular é um método cirúrgico comumente usado no tratamento de pacientes acometidos pela Síndrome da Apnéia Obstrutiva do Sono (SAOS) e portadores de anormalidades anatômicas identificáveis neste complexo, que estreitam e/ou obstruem o espaço aéreo. O intuito deste estudo foi analisar variações cefalométricas do espaço aéreo faríngeo em indivíduos Classe II de Angle, após a cirurgia ortognática. METODOLOGIA: a amostra consistiu de telerradiografias laterais equivalentes aos períodos pré e pós-operatório de 30 indivíduos, divididos no grupo com avanço cirúrgico mandibular (n=15) e no grupo com avanço maxilomandibular (n=15). Os parâmetros cefalométricos usados permitiram avaliar o espaço aéreo posterior em 3 níveis: a hipofaringe (PFI-V), a orofaringe (PFM-PM, PFM-PO, PFM-U, PFM-Up) e a nasofaringe (PFM-PN, pm-PFS). A análise esquelética foi na base do crânio (N-S-Ba) e na mandíbula (Ar-Go-Me). A média das diferenças entre os valores pré e pós-operatórios das mensurações lineares (mm) e angulares (graus) foi avaliada pelo teste t pareado. RESULTADOS E CONCLUSÕES: estatisticamente, não houve redução do espaço aéreo faríngeo pós-avanço cirúrgico. O que se observou foi que apenas PFM-PO e PFS-pM se mantiveram constantes e na maioria restante os valores aumentaram.

Maxillary and mandibular width changes studied using metallic implants.

The purpose of this implant study was to evaluate the transverse stability of the basal maxillary and mandibular structures. The sample included 25 subjects between 12 and 18 years of age who were followed for approximately 2.6 years. Metallic implants were placed bilaterally into the maxillary and mandibular corpora before treatment. Once implant stability had been confirmed, treatment (4 first premolar extractions followed by fixed appliance therapy) was initiated. Changes in the transverse maxillary and mandibular implants were evaluated cephalometrically and two groups (GROW+ and GROW++; selection based on growth changes in facial height and mandibular length) were compared. The GROW++ group showed significant width increases of the posterior maxillary implants (P <.001) and the mandibular implants (P =.009); there was no significant change for the anterior maxillary implants. The GROW+ group showed no significant width changes between the maxillary and mandibular implants. We conclude that (1) there are significant width increases during late adolescence of the basal mandibular and maxillary skeletal structures and (2) the width changes are related with growth potential.

Effects of cervical headgear and edgewise appliances on growing patients

Maxillary basal bone, dentoalveolar, and dental changes in Class II Division 1 patients treated to normal occlusion by using cervical headgear and edgewise appliances were retrospectively evaluated. A sample of 45 treated patients was compared with a group of 30 untreated patients. Subjects were drawn from the Department of Orthodontics, Araraquara School of Dentistry, Brazil, and ranged in age from 7.5 to 13.5 years. The groups were matched based on age, gender, and malocclusion. Roughly 87% of the treated group had a mesocephalic or brachicephalic pattern, and 13% had a dolicocephalic pattern. Cervical headgear was used until a Class I dental relationship was achieved. Our results demonstrated that the malocclusions were probably corrected by maintaining the maxillary first molars in position during maxillary growth. Maxillary basal bone changes (excluding dentoalveolar changes) did not differ significantly between the treated and the untreated groups. Molar extrusion after the use of cervical headgear was not supported by our data, and this must be considered in the treatment plan of patients who present similar facial types. (Am J Orthod Dentofacial Orthop 2001;119:531-9).

A comparison of nasopharyngeal endoscopy and lateral cephalometric radiography in the diagnosis of nasopharyngeal airway obstruction

Two auxiliary methods of diagnosing nasopharyngeal airway obstruction were compared. Cephalometric radiography and nasopharyngeal videoendoscopy were evaluated for efficacy in terms of reproducibility and validity. Thirty orthodontic patients (7 to 12 years of age) seeking otorhinolaryngologic treatment for mouth breathing, or mouth and nose breathing, had nasopharyngeal endoscopy and radiographic examinations performed on the same day. Two otorhinolaryngologists analyzed the results. Nasopharyngeal endoscopy was more reliable in identifying all the obstructive nasopharyngeal processes. Endoscopy obtained kappa index scores of almost perfect agreement for diagnosis of posterior nasal septum deviation, of substantial agreement for anterior nasal septum deviation and lower turbinate hypertrophy, and of moderate agreement for middle turbinate hypertrophy. Lateral cephalometric radiography obtained scores of perfect agreement for imaging hypertrophy of the middle turbinate, of almost perfect agreement for imaging hypertrophy of the posterior portion of the inferior turbinate, and of substantial agreement for imaging hypertrophy of the inferior turbinate. Radiographic diagnoses of hypertrophy of the middle and lower turbinates exhibited high sensitivity and low specificity when compared with diagnoses by nasopharyngeal endoscopy.

Treatment Effects Produced by Fränkel Appliance in Patients with Class II, Division 1 Malocclusion

The purpose of this investigation was to evaluate the dentoalveolar and skeletal cephalometric changes produced by the Fränkel appliance in individuals with a Class II, division 1 malocclusion. Lateral cephalograms of 44 patients of both sexes were divided in two groups of 22 each. The control group was comprised of untreated Class II children with an initial mean age of eight years and seven months who were followed without treatment for a period of 13 months. The Fränkel group had an initial mean age of nine years and was treated for a mean period of 17 months. Lateral cephalometric headfilms of each patient were obtained at the beginning and end of treatment. The Fränkel appliance produced no significant changes in maxillary growth during the evaluation period, while a statistically significant increase in mandibular length was observed. The maxillomandibular relationship improved mostly because of an increase in mandibular length. In addition, there were no statistically significant differences in the craniofacial growth direction between the Fränkel and the control group, both showing a slight downward rotation of the palatal plane. The Fränkel appliance produced a labial tipping of the lower incisors and a lingual inclination of the upper incisors as well as a significant increase in mandibular posterior dentoalveolar height. It was concluded that the main effects of the Fränkel appliance during this time period were mostly dentoalveolar with a smaller but significant skeletal mandibular effect.

Zygomatic bone: Anatomic bases for osseointegrated implant anchorage

Purpose: The aim of the present study was to evaluate zygomatic bone thickness considering a possible relationship between this parameter and cephalic index (Cl) for better use of Cl in the implant placement technique. Materials and Methods: Cl was calculated for 60 dry Brazilian skulls. The zygo matic bones of the skulls were divided into 13 standardized sections for measurement. Bilateral measurements of zygomatic bone thickness were made on dry skulls. Results: Sections 5, 6, 8, and 9 were appropriate for implant anchorage in terms of location. The mean thicknesses of these sections were 6.05 mm for section 5, 3.15 mm for section 6, 6.13 mm for section 8, and 4.75 mm for section 9. In only 1 section, section 8, did mean thickness on 1 side of of the skull differ significantly from mean thickness on the other side (P <.001). Discussion: For the relationship between quadrant thick ness and Cl, sections 6 and 8 varied independently of Cl. Section 5 associated with brachycephaly, and section 9 associated with subbrachycephaly, presented variations in the corresponding thickness. Conclusion: Based on the results, implants should be placed in sections 5 and 8, since they presented the greatest thickness, except in brachycephalic subjects, where thickness was greatest in section 5, and in subbrachycephalic subjects, where thickness was greatest in section 9. Cl did not prove to be an appropriate parameter for evaluating zygomatic bone thickness for this sampling.

A new way of analyzing occlusion 3 dimensionally

This article introduces a new method for 3-dimensional dental cast analysis, by using a mechanical 3-dimensional digitizer, MicroScribe 3DX (Immersion, San Jose, Calif), and TIGARO software (not yet released, but available from the author at hayasaki@dent.kyushu-u.ac.jp). By digitizing points on the model, multiple measurements can be made, including tooth dimensions; arch length, width, and perimeter; curve of Spee; overjet and overbite; and anteroposterior discrepancy. The bias of the system can be evaluated by comparing the distance between 2 points as determined by the new system and as measured with digital calipers. Fifteen pairs of models were measured digitally and manually, and the bias was evaluated by comparing the variances of both methods and checking for the type of error obtained by each method. No systematic errors were found. The results showed that the method is accurate, and it can be applied to both clinical practice and research. Copyright © 2005 by the American Association of Orthodontists.

Short-term treatment effects produced by the herbst appliance in the mixed dentition

This prospective clinical investigation evaluates the dentoalveolar and skeletal cephalometric changes produced by the Herbst appliance during treatment of mixed dentition patients with Class II division 1 malocclusion. Thirty individuals (15 male and 15 female individuals; initial mean age nine years 10 months) were treated with the Herbst appliance for a period of 12 months. For comparison, the records of 30 untreated Class II children (15 boys, 15 girls; initial mean age nine years eight months) were followed without treatment for a period of 12 months. The results indicated that the treatment effects produced in the mixed dentition patients were primarily dentoalveolar in nature. The mandibular incisors were tipped labially, and the maxillary incisors were retruded; a significant increase in mandibular posterior dentoalveolar height occurred, and there was a restriction in the vertical development of the maxillary molars. There was no difference in the forward growth of the maxilla between the two groups. In comparison with the controls, however, the Herbst treatment produced a modest but statistically significant increase in total mandibular length. This increase in total mandibular length, however, was less than that observed in adolescent Herbst patients in other studies. © 2005 by The EH Angle Education and Research Foundation, Inc.

The mandibular lingula's position in children as a reference to inferior alveolar nerve block

Purpose: The objective of this study was to evaluate the position of the mandibular lingula (ML) to provide data for inferior alveolar nerve block techniques in children. Methods: One hundred fifty-four panoramic radiographs of 7- to 10-year-old boys and girls were analyzed. Measurements were taken from the ML to the occlusal plane, and the percentile distances of the ML to ramal borders were determined. Results: The distance between the ML and the occlusal plane showed a gradual increase, but only in the male group was it statistically significant. MLs ratio position on the ramus remained constant in all analyzed groups. In the 7-year-old group, the ML was observed above the occlusal plane in 70% of girls and 55% of boys. That percentage reached 85% of all children by age 10. Conclusions: The mandibular lingula's ratio position remained constant. Inferior alveolar anesthesia should be administered at least 6 mm above the occlusal plane in 7- to 8-year-old children, while 10 mm could be indicated for 9- to 10-year-old children. The mandibular lingula should be considered a reliable reference for further studies of inferior alveolar nerve block techniques.

Skeletal maturation analysis by morphological evaluation of the cervical vertebrae

The determination of skeletal maturation by morphological evaluation of the cervical vertebrae was evaluated in a 100 cephalograms. The analysis showed that this method was reproducible for assessing the individual's growth curve.

Esthetic influence of negative space in the buccal corridor during smiling

The purpose of this study was to measure and verify the esthetic influence of the bilateral spaces between maxillary teeth and lip corners, called negative space (NS), during smile. The sample was comprised of 60 smile photographs obtained from 60 individuals (30 men and 30 women) aged 18 to 25 years old. Two orthodontists and two lay people evaluated these pictures regarding esthetics by a visual analogue scale. In each picture, the right and left NS were measured in millimeters and in proportion to the smile width (SW). Data were analyzed for statistical significance (P = .05). The mean NS of the sample was 6.68 ± 1.99 mm, and the NS proportion in relation to the SW was 9.6 ± 2.56%, for both sides of the arch. No significant asymmetries were observed between the right and left sides. The NS was significantly larger in men than in women when measured in millimeters (P = .028) (7.08 ± 2.24 mm in men vs 6.28 ± 1.62 mm in women), but the NS proportion to the SW was similar (9.94 ± 2.24% in men vs 9.26 ± 1.61% in women). When the 12 individuals with the smallest NS in proportion to SW were compared with the 12 individuals with the largest NS in proportion to SW, there was no statistical difference regarding the esthetic evaluation (P = .11). It was concluded that the NS did not influence the esthetic evaluation of smile photographs in the sample in this study, for both orthodontists and lay people. © 2006 by The EH Angle Education and Research Foundation, Inc.

Periodontal effects of rapid maxillary expansion with tooth-tissue-borne and tooth-borne expanders: A computed tomography evaluation

Introduction: The force delivered during rapid maxillary expansion (RME) produces areas of compression on the periodontal ligament of the supporting teeth. The resulting alveolar bone resorption can lead to unwanted tooth movement in the same direction. The purpose of this study was to evaluate periodontal changes by means of computed tomography after RME with tooth-tissue-borne and tooth-borne expanders. Methods: The sample comprised 8 girls, 11 to 14 years old, with Class I or II malocclusions with unilateral or bilateral posterior crossbites Four girls were treated with tooth-tissue-borne Haas-type expanders, and 4 were treated with tooth-borne Hyrax expanders. The appliances were activated up to the full 7-mm capacity of the expansion screw. Spiral CT scans were taken before expansion and after the 3-month retention period when the expander was removed. One-millimeter thick axial sections were exposed parallel to the palatal plane, comprising the dentoalveolar area and the base of the maxilla up to the inferior third of the nasal cavity. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal alveolar bone crest level by means of the computerized method. Results and Conclusions: RME reduced the buccal bone plate thickness of supporting teeth 0.6 to 0.9 mm and increased the lingual bone plate thickness 0.8 to 1.3 mm. The increase in lingual bone plate thickness of the maxillary posterior teeth was greater in the tooth-borne expansion group than in the tooth-tissue-borne group. RME induced bone dehiscences on the anchorage teeth's buccal aspect (7.1 ± 4.6 mm at the first premolars and 3.8 ± 4.4 mm at the mesiobuccal area of the first molars), especially in subjects with thinner buccal bone plates. The tooth-borne expander produced greater reduction of first premolar buccal alveolar bone crest level than did the tooth-tissue-borne expander. © 2006 American Association of Orthodontists.

Analysis of the smile photograph.

Optimal facial esthetics is one of the objectives in orthodontic treatment and an important issue in modern society. In this context, orthodontic treatment permits individuals with dental malpositions to achieve improved dentofacial esthetics. To reach this result, the orthodontist needs to recognize the characteristics considered normal and pleasant in dental arches and smiles. The objective of this article is to review and discuss criterion adopted by dental literature to technically analyze the smile, such as dental midline, smile line, dental exposure, negative space, dental proportion, and symmetry. This article proposes a way to visualize an ideal smile for each patient.