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.

Influence of age on combined effects of cyclosporin and nifedipine on rat alveolar bone

Background: There is some evidence showing that cyclosporin A (CsA) and nifedipine (NIF) affect bone metabolism. The purpose of this work was to study the effects of CsA and NIF, given alone or concurrently, on alveolar bone of rats of different ages. Methods: Rats 15, 30, 60, and 90 days old were treated daily with 10 mg/kg body weight of CsA subcutaneously injected and/or 50 mg/kg body weight of NIF/day given orally for 60 days. Alveolar bone of the first lower molars was morphologically and stereologically evaluated in serial 5 μm bucco-lingual paraffin sections, stained with hematoxylin and eosin. Serum calcium and alkaline phosphatase levels were measured in all animals at the end of the experimental period. Results: Rats treated with CsA or NIF alone or CsA and NIF concurrently showed decreased alveolar bone density. CsA was more effective than NIF. A significant decrease in serum calcium was found only in animals treated with CsA or CsA/NIF. The results were similar regardless of age. Conclusions: These results indicate that the decrease in the alveolar bone volume in rats caused by CsA and NIF alone or concurrently is not age dependent. Furthermore, NIF (50 mg/kg) did not further increase the loss of alveolar bone volume induced by CsA (10 mg/kg).

Natal maxillary primary molars: Case report

An unusual case of a newborn with two immature natal maxillary molars is presented. Clinical and histological examination showed that the teeth were rootless and incompletely mineralized. The patient was followed up during one year and we confirmed that the natal teeth were from normal primary series.

Temperature analysis during bonding of brackets using LED or halogen light base units

The purpose of our investigation is to compare the intrapulpal temperature changes following blue LED system and halogen lamp irradiation at the enamel surface of permanent teeth. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Several light sources can be used: halogens, arc plasma, lasers, and recently blue LED systems. An important aspect to be observed during such a procedures is the temperature change. In this study, we have used nine human extracted permanent teeth: three central incisors, three lateral incisors, and three canines. Teeth were exposed to two light sources: blue LED system (preliminary commercial model LEC 470-II) and halogen lamp (conventional photo-cure equipment). The surface of teeth was exposed for 20, 40, and 60 sec at the buccal and lingual enamel surface with an angle of 45 degrees. Temperature values measured by a thermistor placed at pulpar chamber were read in time intervals of 1 sec. We obtained plots showing the temperature evolution as a function of time for each experiment. There is a correlation between heating quantity and exposition time of light source: with increasing exposition time, heating increases into the pulpal chamber. The halogen lamp showed higher heating than the LED system, which showed a shorter time of cooling than halogen lamp. The blue LED system seems like the indicated light source for photo-cure of composite resin during the bonding of brackets. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Blue LED equipment did not heat during its use. This could permit a shorter clinical time of operation and better performance. © Mary Ann Liebert, Inc.

Effect of 0.4% stannous fluoride gel on Streptococci mutans in relation to elastomeric rings and steel ligatures in orthodontic patients

Background: Patients with fixed orthodontic appliances often experience an absolute increase in the number of Streptococci mutans colony-forming units (cfu). The aim of this investigation was to study the development of biofilm and S. mutans cfu in connection with stainless steel ligatures and elastomeric rings in orthodontic patients treated with and without 0.4% stannous fluoride gel (SFG). Material: Forty-seven patients were divided into 2 groups: those treated with 0.4% SFG for 4 minutes (experimental) and those without 0.4% SFG (control). In each patient, elastomeric rings were used for ligation on 1 side of the dental arch midline, and stainless steel ligatures were used on the opposite side. Saliva samples were collected before and after appliance placement. At 15 and 30 days after appliance placement, biofilm samples from the stainless steel ligatures and the elastomeric rings were collected and subjected to microbiologic procedures and scanning electron microscopy (SEM) analysis. Results: The numbers of S. mutans cfu in the saliva and biofilm were not statistically different between the teeth fitted with elastomeric rings and stainless steel ligatures, or between the experimental and control groups. SEM analysis showed biofilm formation on both ligature ties. Conclusions: Topical application of 0.4% SFG in orthodontic patients with elastomeric rings or stainless steel ligatures does not cause a significant decrease in S. mutans cfu in the saliva and biofilm. Copyright © 2005 by the American Association of Orthodontists.

SEM analysis of internal adaptation of adhesive restorations after contamination with saliva

Purpose: This study tested the null hypothesis that different treatments of saliva-contaminated substrate would not affect microgap formation at the dentin walls of bonded restorations. Materials and Methods: Forty freshly extracted human molars received standardized Class V preparations on buccal and lingual surfaces. The specimens were assigned to four experimental groups (n = 20): [G1] no contamination (control group), [G2] saliva contamination (10 s) after etching followed by 5 s air stream; [G3] saliva contamination after etching and rinsed for 10 s; and [G4] re-etching for 10 s after saliva contamination. All specimens were restored with a one-bottle adhesive (Single Bond, 3M ESPE) and microhybrid composite resin (Filtek Z250, 3M ESPE) according to the manufacturer's instructions. The specimens were thermocycled, sectioned through the center of the restoration, and then processed for SEM. Microgaps were measured at the axial wall at 1500X magnification. The data were submitted to Kruskal-Wallis nonparametric statistical analysis at p < 0.05. Results: The data revealed that different groups resulted in a statistically significant difference (p < 0.01) in gap formation. Air drying [G2] and rinsing [G3] the saliva-contaminated dentin resulted in similar microgap values (p > 0.05). However, re-etching the dentin after saliva contamination [G4] increased microgap formation (p < 0.05) when compared with the groups G1 and G2. Although air drying and rinsing produced results comparable to noncontaminated dentin, the presence of microgaps was not completely eliminated. Conclusion: Contaminated saliva did not prevent hybrid layer formation; however, it did reduce the adaptation of the restorative material to bonded surfaces.

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.

Scanning electron microscope analysis of internal adaptation of materials used for pulp protection under composite resin restorations

Purpose: The aim of this study was to evaluate the interfacial microgap with different materials used for pulp protection. The null hypothesis tested was that the combination of calcium hydroxide, resin-modified glass ionomer, and dentin adhesive used as pulp protection in composite restorations would not result in a greater axial gap than that obtained with hybridization only. Materials and Methods: Standardized Class V preparations were performed in buccal and lingual surfaces of 60 caries-free, extracted human third molars. The prepared teeth were randomly assessed in six groups: (1) Single Bond (SB) (3M ESPE, St. Paul, MN, USA); (2) Life (LF) (Kerr Co., Romulus, MI, USA) + SB; (3) LF + Vitrebond (VT) (3M ESPE) + SB; (4) VT + SB; (5) SB + VT; (6) SB + VT + SB. They were restored with microhybrid composite resin Filtek Z250 (3M ESPE), according to the manufacturer's instructions. However, to groups 5 and 6, the dentin bonding adhesive was applied prior to the resin-modified glass ionomer. The specimens were then thermocycled, cross-sectioned through the center of the restoration, fixed, and processed for scanning electron microscopy. The specimens were mounted on stubs and sputter coated. The internal adaptation of the materials to the axial wall was analyzed under SEM with × 1,000 magnification. Results: The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p ≤ .05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction with each other (p < .001) resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration. ©2005 BC Decker Inc.

Methods and tools for encoding the WordNet.Br sentences, concept glosses, and conceptual-semantic relations

This paper presents the overall methodology that has been used to encode both the Brazilian Portuguese WordNet (WordNet.Br) standard language-independent conceptual-semantic relations (hyponymy, co-hyponymy, meronymy, cause, and entailment) and the so-called cross-lingual conceptual-semantic relations between different wordnets. Accordingly, after contextualizing the project and outlining the current lexical database structure and statistics, it describes the WordNet.Br editing GUI that was designed to aid the linguist in carrying out the tasks of building synsets, selecting sample sentences from corpora, writing synset concept glosses, and encoding both language-independent conceptual-semantic relations and cross-lingual conceptual-semantic relations between WordNet.Br and Princeton WordNet © Springer-Verlag Berlin Heidelberg 2006.

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.