Intercommissural width in 4 racial groups as a guide for the selection of maxillary anterior teeth in complete dentures

Purpose: To determine whether intercommissural width is a reliable guide for the selection of maxillary denture teeth width. Materials and Methods: Casts were made of 160 subjects from 4 different racial groups. Locations of intercommissural width landmarks (the corners of the mouth) were made on the subjects and transferred to the casts. The distances between the corners of the mouth and the distal of the canines were measured on the casts and compared. Results: A weak correlation was found between the distal of the canines and the distance between the corners of the mouth in the 4 racial groups. Conclusion: The use of the corners of the mouth for the selection of artificial teeth is generally inaccurate.

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.

Bone reformation and implant integration following maxillary sinus membrane elevation: An experimental study in primates

Background: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell™, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone-implant contact, bone area in threads, and bone area in rectangle). Results: The results showed no differences between membrane-elevated and grafted sites regarding implant stability, bone-implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone-implant contact and bone area within threads were observed. Conclusions: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum-alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures. © 2006 Blackwell Publishing, Inc.

Nasal width as a guide for the selection of maxillary complete denture anterior teeth in four racial groups

Purpose: Selecting artificial teeth for edentulous patients is difficult when pre-extraction records are not available. Various guidelines have been suggested for determining the width of the maxillary anterior denture teeth. This study was undertaken to evaluate the use of the nasal width as a guide for the selection of proper width maxillary anterior denture teeth in four racial groups of the Brazilian population. Materials and Methods: One hundred and sixty subjects (40 Whites, 40 Mulattos, 40 Blacks, and 40 Asians) were selected. Using a sliding caliper, the nasal width and the intercanine distance were measured. The Pearson product-moment correlation coefficient was used to determine the relationship between the above measurements. A prediction was made of the percentage of subjects of the White, Mulatto, Black, and Asian populations in which the selection error due to the clinical application of the method of the nasal width would be within 0 to 2 mm, within 2 to 4 mm, and greater than 4 mm. Results: The four racial groups showed a weak correlation between the intercanine distance and the nasal width. In 39.7% of the White, 55.7% of the Mulatto, 81.9% of the Black, and 48.2% of the Asian populations, errors greater than 4 mm would be present with the use of the nasal width. Conclusions: The correlation found between the intercanine distance and the nasal width was not high enough to be used as a predictive factor. The relationship between natural tooth width and artificial tooth width as predicted by the nasal width showed that the nasal width method is not accurate for all the studied groups. Copyright © 2006 by The American College of Prosthodontists.

Insertion of the superior head of the lateral pterigoid muscle in the human fetuses

The lateral pterygoid muscle, more specifically its superior head, as we know, is closely related to the temporomandibular joint (TMJ). Particularly in children, in contrast with what was observed in adults, these joints have been rarely studied, by the anatomic functional aspect, little knowing about its functions in the embryonic and fetal periods. We used, in this work, 12 fetuses ranging in age from 16 to 39 weeks of intrauterine life, where we observed that the superior head of the lateral pterygoid muscle is inserted in the disc and in the articular capsule, in all age groups studied, and also, that the fibers and the thickness of the articular disc is, as well as the articular capsule suffer modifications in accordance with the period of development. © 2007 Sociedad Chilena de Anatom•br>.

Maxillary canine - First premolar transposition: Restoring normal tooth order with segmented mechanics

Tooth transpositions present at a relatively low incidence in the world population and primarily affect maxillary canines and premolars. Treatment of this disturbance should take into account aspects such as facial pattern, age, malocclusion, tooth-size discrepancy, stage of eruption, and magnitude of the transposition. Mechanics for correction should be entirely individualized, reducing the risks and adverse effects. Practitioners often select simpler options, indicating extraction of permanent teeth, which is an irreversible procedure that may bring about damages to the patient. This study presents a case report and treatment of unilateral transposition of maxillary canine and premolar with repositioning of affected teeth to their respective normal positions. © 2006 by The EH Angle Education and Research Foundation, Inc.

Tissue inhibitor of metalloproteinase-2 (TIMP-2) location in the ventral, lateral, dorsal and anterior lobes of rat prostate by immunohistochemistry

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a major role in extracellular matrix component degradation in several normal and abnormal tissue situations; they are also found in human seminal plasma. MMPs have been found in rat prostate secretions and are nearly lobe specific in expression pattern. The aim of this study was to evaluate whether TIMP-2, like other semen components, is expressed differently from different rat prostatic lobes. Immunohistochemical staining was performed in both young and adult rat ventral (VP), lateral (LP), dorsal (DP), and anterior (AP) prostatic lobes and confirmed by western blotting. TIMP-2 expression was found in the epithelial cells in the following sequence: LP > AP > DP > VP, in both young and adult rats. In this study, 100% of adult LP presented histological signs of prostatitis, where TIMP-2 immunostaining was positive in normal epithelium even with intraluminal neutrophils, but was reduced or absent in the epithelium with intraepithelial leukocytes or with periductal stroma disorganization associated with mononuclear cell infiltration. However, TIMP-2 expression in LP was not induced by prostatitis, since younger rat LPs were also strongly TIMP-2 positive. The distal and intermediate VP regions were TIMP-2 negative, but the proximal regions were strongly stained. Western blotting results confirmed the high TIMP-2 expression in the LP lobe. Thus, TIMP-2 is expressed differently between the prostatic lobes and is another nearly lobe-specific protein, which plays a role in the regulation of MMP activity in seminal plasma and glandular homeostasis. TIMP-2 is also another regional ductal variation of VP. Further studies should address whether TIMP-2 expression is related to the highest incidence of rat LP prostatitis and adenocarcinoma. © 2006 International Federation for Cell Biology.

Root trunk height as a risk factor for periodontal furcation involvement in maxillary first molars: an in vitro study.

The aim of this study was to correlate the root trunk height from the furcation openings on the buccal, mesial and distal surfaces to the cemento-enamel junction in upper first permanent molars in human beings with risk for periodontal disease progression. One hundred extracted maxillary first molars were used. Reference points and demarcations were determined from the entrance of the buccal (F1), mesial (F2) and distal (F3) furcations to the cemento-enamel junction in millimeters. The mean distances found were 3.50 mm, 4.44 mm and 4.26 mm for the buccal, mesial and distal furcations, respectively, in relation to the cemento-enamel junction. The statistical analyses were Student's t-test and Chi-square (X2). With periodontal disease progression, the buccal furcation presents a greater compromising risk due to its proximity to the cemento-enamel junction, while the mesial furcation is the most distant, comprising a lesser risk.

Regional odontodysplasia: Case report

Regional odontodysplasia (RO) is a rare developmental anomaly involving both mesodermal and ectodermal dental components in a group of contiguous teeth. It affects the primary and permanent dentitions in the maxilla and mandible or both jaws. Generally it is localized in only one arch. The etiology of this dental anomaly is uncertain. Clinically, affected teeth have an abnormal morphology, are soft on probing and typically discolored, yellow or yellowish-brown. Radiographically, the affected teeth show a ghostlike appearance. This paper reports the case of a 5-year-old girl presenting this rare anomaly on the left side of the maxillary arch, which crossed the midline. The primary maxillary left teeth (except for the canine) and the primary maxillary right central incisor were missing due to previous extractions. The permanent teeth had a ghostlike appearance radiographically. The treatment performed was rehabilitation with temporary partial acrylic denture and periodic controls. In the future, the extraction of affected permanent teeth and rehabilitation with dental implants will be evaluated. The presentation of this case adds valuable information to pediatric dentists to review special clinical and radiographic features of RO, which will facilitate the diagnosis and treatment of patients with this condition.

Enhancement of meal-associated hypertonic NaCl intake by moxonidine into the lateral parabrachial nucleus

α2-Adrenoceptor activation with moxonidine (α2-adrenergic/imidazoline receptor agonist) into the lateral parabrachial nucleus (LPBN) enhances angiotensin II/hypovolaemia-induced sodium intake and drives cell dehydrated rats to ingest hypertonic sodium solution besides water. Angiotensin II and osmotic signals are suggested to stimulate meal-induced water intake. Therefore, in the present study we investigated the effects of bilateral injections of moxonidine into the LPBN on food deprivation-induced food intake and on meal-associated water and 0.3 M NaCl intake. Male Holtzman rats with cannulas implanted bilaterally into the LPBN were submitted to 14 or 24 h of food deprivation with water and 0.3 M NaCl available (n = 6-14). Bilateral injections of moxonidine (0.5 nmol/0.2 μl) into the LPBN increased meal-associated 0.3 M NaCl intake (11.4 ± 3.0 ml/120 min versus vehicle: 2.2 ± 0.9 ml/120 min), without changing food intake (11.1 ± 1.2 g/120 min versus vehicle: 11.2 ± 0.9 g/120 min) or water intake (10.2 ± 1.5 ml/120 min versus vehicle: 10.4 ± 1.2 ml/120 min) by 24 h food deprived rats. When no food was available during the test, moxonidine (0.5 nmol) into the LPBN of 24 h food-deprived rats produced no change in 0.3 M NaCl intake (1.0 ± 0.6 ml/120 min versus vehicle: 1.8 ± 1.1 ml/120 min), nor in water intake (0.2 ± 0.1 ml/120 min versus vehicle: 0.6 ± 0.3 ml/120 min). The results suggest that signals generated during a meal, like dehydration, for example, not hunger, induce hypertonic NaCl intake when moxonidine is acting in the LPBN. Thus, activation of LPBN inhibitory mechanisms seems necessary to restrain sodium intake during a meal. © 2007 Elsevier B.V. All rights reserved.

Prevalence of dental trauma in patients with cerebral palsy

This study presents the findings of a record review that evaluated the prevalence of dental trauma in patients with cerebral palsy and evaluated its possible relationship with age, type of palsy, and epilepsy. The dental records of 2,200 patients with special needs admitted to the special care clinic of the School of Dentistry of Araçatuba/UNESP, Brazil, between 1998 and 2003 were reviewed. Of the records that were analyzed, 500 patients who had cerebral palsy were selected for this study. Information regarding age, gender, type of palsy and dental trauma was collected and statistically analyzed. It was observed that 10.6% of the subjects (n = 53) had sustained dental trauma. The number of traumatized teeth was 84. Enamel or enamel/dentin fractures were the most frequent types of traumatic injury (84.9%). The permanent maxillary central incisors were the most commonly affected teeth (50%). The frequency of traumatic injuries showed no significant correlation (p>.05) with the type of cerebral palsy or gender and they were more frequent in subjects between the ages of 0 and 12 years. Having epilepsy was not a statistically significant risk factor (p>.05) for dental trauma. © 2008 Special Care Dentistry.

Alterações dentoesqueléticas e do perfil facial em pacientes tratados ortodonticamente com extração de quatro primeiros pré-molares

Objective: the purpose of this prospective study was to cephalometrically analyze the dentoalveolar and soft tissue changes after the orthodontic treatment followed by the extraction of four premolars. Material and methods: the sample was comprised by 30 Class II division 1 patients with mean initial age of 12 years and 4 months. Two lateral cephalograms were obtained from each patient at the beginning and at the end of the treatment. The variables analyzed were the nasalabial changes and upper and lower incisors changes in relation to a vertical and horizontal x and y reference lines. Results: upper and lower incisors retraction was 3.4 and 1.8mm, respectively. The SNA angle was decresead by 1.7 degrees followed by a retraction of point A mainly due to the upper incisor retraction. There was a significant decrease of the Wits and ANB variables. There was an increase in the lower anterior facial height. Upper incisor retraction was followed by an increase in the nasolabial angle (ratio 1:2.8 degrees). However, a wide range of individual variability was found. Conclusions: the present study did not support the simple expectation that treatment with extractions of four premolars will result in a dished in face. It appeared that facial changes were more related to a normal facial growth, the amount of incisor retraction and the anchorage control during the upper and lower incisor.

In vitro assessment of pulp chamber temperature of different teeth submitted to dental bleaching associated with LED/laser and halogen lamp appliances

This study sought to assess the pulp chamber temperature in different groups of human teeth that had been bleached using hydrogen peroxide gel activated with halogen lamps or hybrid LED/laser appliances. Four groups of ten teeth (maxillary central incisors, mandibular incisors, mandibular canines, and maxillary canines) were used. A digital thermometer with a K-type thermocouple was placed inside pulp chambers that had been filled with thermal paste. A 35% hydrogen peroxide-based red bleaching gel was applied to all teeth and photocured for a total of three minutes and 20 seconds (five activations of 40 seconds each), using light from an LED/laser device and a halogen lamp. The temperatures were gauged every 40 seconds and the data were analyzed by three-way ANOVA, followed by Tukey's test. Regardless of the light source, statistically significant differences were observed between the groups of teeth. The mean temperature values (±SD) were highest for maxillary central incisors and lowest for mandibular canines. The halogen lamp appliance produced more pulp chamber heating than the LED/laser appliance. The increase in irradiation time led to a significant increase in temperature.

Dual path: A concept to improve the esthetic replacement of missing anterior teeth with a removable partial denture

The dual path of insertion concept for removable partial denture (RPD) design may be used in esthetically demanding situations. When compared to conventional RPDs, the main advantage of this design is the minimal use of clasps. This clinical report describes the treatment of a patient with an anterior maxillary edentulous area using a dual path RPD. The diagnostic cast was surveyed to ensure the adequacy of the undercuts on the mesial surfaces of the anterior abutments, where rigid minor connectors were placed. Inverted V-shaped canine cingulum rest seats were prepared to provide resistance to tooth movement during function. The dual path RPD concept allows excellent esthetic results, minimizes tooth preparation, and reduces the tendency toward plaque accumulation in a Kennedy class IV partially edentulous arch. © 2008 by The American College of Prosthodontists.