Perception of the esthetic impact of mandibular incisor extraction treatment on laypersons, dental professionals, and dental students

Objective: To evaluate the degree of perception of laypersons, dental professionals, and dental students regarding dental esthetics in cases with mandibular central incisor extraction. Materials and Methods: Using a smile photograph of a person with normal occlusion and all teeth, modifications were made to reflect the extraction of a mandibular incisor of various compositions and sizes. For this purpose a program specifically for image manipulation (Adobe Photoshop CS3, Adobe Systems Inc) was used. After manipulation the images were printed on photographic paper, attached to a questionnaire and distributed to laypersons, dental professionals, and dental students (n = 90) to evaluate the degree of perception and esthetic using a scale of attractiveness, where 0 = hardly attractive, 5 = attractive, and 10 = very attractive. The differences between examiners were checked by the Mann-Whitney test. All the statistics were performed with a confidence level of 95%. Results: The results demonstrated the skill of the dental professionals and dental students in perceiving the difference between cases of normal occlusion and cases where an incisor was lacking (P < .05). The photograph in which the lateral incisors were shown to be larger than the central incisor was the one that obtained the highest value among the cases of extraction in all groups of evaluators. Conclusions: It can be concluded that dental professionals and dental students are more skillful at identifying deviation from normality. In addition, central incisor extraction should always be discarded when there are other treatment options available. (Angle Orthod. 2012;82:732-738.)

Assessment of a Neurophysiological Model of the Mandibular Branch of the Facial Nerve in Rats by Electromyography

Objectives: Our objective was to develop an experimental model for the noninvasive and objective evaluation of facial nerve regeneration in rats using a motor nerve conduction test (electromyography). Methods: Twenty-two rats were submitted to neurophysiological evaluation using motor nerve conduction of the mandibular branch of the facial nerve to obtain the compound muscle action potentials (CMAPs). To record the CM APs, we used two needle electrodes that were inserted into the lower lip muscle of the rat. A supramaximal electrical stimulus was applied, and the values of CMAP latency, amplitude, length, area, and stimulus intensity obtained from each side were compared by use of the Wilcoxon test. Results: There was no significant difference (all p > 0.05) in latency, amplitude, duration, area, or intensity of stimuli between the two sides. The amplitudes ranged between 1.61 and 8.30 mV, the latencies between 1.03 and 1.97 ms, and the stimulus intensities between 1.50 and 2.90 mA. Conclusions: This is a noninvasive, easy, and highly reproducible method that contributes to an improvement of the techniques previously described and may contribute to future studies of the degeneration and regeneration of the facial nerve.

Mandibular Bisphosphonate-Related Osteonecrosis After Dental Implant Rehabilitation: A Case Report

It has been a matter of debate as to whether dental implant therapies are suitable for patients subjected to long-term use of bisphosphonates (BPs). This report presents a case of a 76-year-old woman who developed BPs-related osteonecrosis of the jaw (BRONJ) in the left hemimandible after dental implant exposure. The implants and the necrotic crestal bone were removed, and postoperatively, a delay in tissue healing with bone exposure was noticed. The histologic analysis of the block biopsies revealed a lamellar bone tissue exhibiting necrotic areas and bacterial colonies associated with the bone outer surface. The bone-implant interface showed viable lamellar bone with enlarged vascular spaces in the areas between the implant threads. The possible mechanisms for the loss of implants in BRONJ patients are discussed, and the potential protocols for dental implant rehabilitation for patients under BP therapies are presented. (Implant Dent 2012;21:449-453)

Morphologic micro–computed tomography analysis of mandibular premolars with three root canals

Introduction: This study aimed to describe the anatomy of mandibular premolars with type IX canal configuration by using micro–computed tomography. Methods: Mandibular premolars with radicular grooves (n = 105) were scanned, and 16 teeth with type IX configuration were selected. Number and location of canals, distances between anatomic landmarks, occurrence of apical delta, root canal fusion, and furcation canals, as well as 2-dimensional (area, perimeter, roundness, major and minor diameters) and 3-dimensional (volume, surface area, and structuremodel index) analysis were performed. Data were statistically compared by using analysis of variance and Kruskal-Wallis tests (a = 0.05). Results: Overall, specimens had 1 root with a main canal that divided into mesiobuccal, distobuccal, and lingual canals at the furcation level. Mean length of the teeth was 22.9 2.06 mm, and the configuration of the pulp chamber was mostly triangle-shaped. Mean distances from the furcation to the apex and cementoenamel junction were 9.14 2.07 and 5.59 2.19 mm, respectively. Apical delta, root canal fusion, and furcation canals were present in 4, 5, and 10 specimens, respectively. No statistical differences were found in the 2-dimensional and 3-dimensional analyses between root canals (P > .05). Conclusions: Type IX configuration of the root canal system was found in 16 of 105 mandibular premolars with radicular grooves. Most of the specimens had a triangle-shaped pulp chamber. Within this anatomic configuration, complexities of the root canal systems such as the presence of furcation canals, fusion of canals, oval-shaped canals in the apical third, small orifices at the pulp chamber level, and apical delta were also observed

Estabilidade em longo prazo do tratamento da má oclusão de classe II, divisão 1, com a utilização de um aparelho funcional propulsor mandibular fixo: relato de caso

O tratamento da má oclusão de Classe II sem extrações dentárias vem ganhando popularidade na comunidade ortodôntica já há três décadas. Aparelhos funcionais fixos vêm sendo utilizados por profissionais, de maneira crescente, para promover compensações dentoalveolares e corrigir a má oclusão de Classe II. Os efeitos mais significativos são observados em pacientes com padrão de crescimento horizontal. Um caso clínico será relatado com o uso do aparelho fixo Twin Force Bite Corrector em uma paciente do sexo feminino, para a correção da Classe II. Esse dispositivo de ancoragem fixa dispensa o uso de aparelhos funcionais removíveis e não necessita da cooperação do paciente.

Correlation between maxillary central incisor crown morphology and mandibular dental arch form in normal occlusion subjects

The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were obtained. These were printed and placed in an album below pre-set models of arches and dental crowns, and distributed to 12 dental surgeons, who were asked to choose which shape was most in accordance with the models and crown presented. The Kappa test was performed to evaluate the concordance among evaluators while the chi-square test was used to verify the association between the dental arch and central incisor morphology, at a 5% significance level. The Kappa test showed moderate agreement among evaluators for both variables of this study, and the chi-square test showed no significant association between tooth shape and mandibular dental arch morphology. It may be concluded that the use of arch morphology as a diagnostic method to determine the shape of the maxillary central incisor is not appropriate. Further research is necessary to assess tooth shape using a stricter scientific basis.

Coronoid process hyperplasia: an unusual cause of mandibular hypomobility

A large number of disorders affecting the masticatory system can cause restriction of mouth opening. The most common conditions related to this problem are those involving the temporomandibular joint (TMJ) and the masticatory muscles, when facial pain also is an usual finding. Congenital or developmental mandibular disorders are also possible causes for mouth opening limitation, although in a very small prevalence. Coronoid process hyperplasia (CPH) is an example of these cases, characterized by an excessive coronoid process growing, where mandibular movements become limited by the impaction of this structure on the posterior portion of the zygomatic bone. This condition is rare, painless, usually bilateral and progressive, affecting mainly men. Diagnosis of CPH is made based on clinical signs of mouth opening limitation together with imaging exams, especially panoramic radiography and computerized tomography (CT). Treatment is exclusively surgical. This paper presents a case of a male patient with bilateral coronoid process hyperplasia, initially diagnosed with bilateral disk displacement without reduction, and successfully treated with intraoral coronoidectomy. It is emphasized the importance of differential diagnosis for a correct diagnosis and, consequently, effective management strategy.

Effect of sodium hypochlorite and edta irrigation, individually and in alternation, on dentin microhardness at the furcation area of mandibular molars

The aim of this study was to evaluate the effect of irrigation regimens on dentin microhardness at the furcation area of mandibular molars, using sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA), individually and in alternation. The occlusal surface and the roots of 20 non-carious extracted human permanent mandibular molars were cut transversally and discarded. The tooth blocks were embedded in acrylic resin and randomly assigned to 4 groups (n=5) according to the irrigating regimens: 1% NaOCl solution, 17% EDTA solution, 1% NaOCl and 17% EDTA and distilled water (control). Knoop microhardness of dentin at the furcation area was evaluated. Data were analyzed using one-way ANOVA and Tukey's multiple comparison tests (α=0.05). The results of this study indicated that all irrigation solutions, except for distilled water (control), decreased dentin microhardness. EDTA did not show a significant difference with NaOCl/EDTA (p>0.05), but showed a significant difference with NaOCl (p<0.01). EDTA and NaOCl/EDTA showed a maximum decrease in microhardness. The 17% EDTA solution, either alone or in combination with 1% NaOCl reduced significantly dentin microhardness at the furcation area of mandibular molars.

Treatment of snoring and sleep apnea syndrome with a removable mandibular advancement device in patients without TMD

INTRODUCTION: Among the sleep disorders reported by the American Academy of Sleep, the most common is obstructive sleep apnea-hypopnea syndrome (OSAHS), which is caused by difficulties in air passage and complete interruption of air flow in the airway. This syndrome is associated with increased morbidity and mortality in apneic individuals. OBJECTIVE: It was the objective of this paper to evaluate a removable mandibular advancement device as it provides a noninvasive, straightforward treatment readily accepted by patients. METHODS: In this study, 15 patients without temporomandibular disorders (TMD) and with excessive daytime sleepiness or snoring were evaluated. Data were collected by means of: Polysomnography before and after placement of an intraoral appliance, analysis of TMD signs and symptoms using a patient history questionnaire, muscle and TMJ palpation. RESULTS: After treatment, the statistical analysis (t-test, and the "before and after" test) showed a mean reduction of 77.6% (p=0.001) in the apnea-hypopnea index, an increase in lowest oxyhemoglobin saturation (p=0.05), decrease in desaturation (p=0.05), decrease in micro-awakenings or EEG arousals (p=0.05) and highly significant improvement in daytime sleepiness (p=0.005), measured by the Epworth Sleepiness Scale. No TMD appeared during the monitoring period. CONCLUSION: The oral device developed in this study was considered effective for mild to moderate OSAHS.

Carcinoma de células escamosas em glândula mamária de gata doméstica

Background: In the feline species, 80% to 93% of neoplasias in the mammary gland are malignant, being the majority carcinomas. Among them, there is the mammary squamous cell carcinoma, which amounts to a very rare neoplasm in the domestic cat, with considerable potential for malignancy. This study aimed to report a case of squamous cell mammary carcinoma in the feline species. Case: A female cat, mixed breed, ten years old, presented history of skin lesion. The cat had been spayed two years before, but with previous administration of contraceptives. At the physical examination, it was observed ulcer between the caudal abdominal mammary glands. The occurrence of skin or mammary neoplasia was conceived. The following complementary tests were requested: complete blood count, serum biochemical profi le (renal and hepatic), chest radiographs, abdominal ultrasound, and incisional biopsy of the ulcerated region periphery, followed by classic histopathology. The lesion histopathology was compatible with squamous cell carcinoma of the mammary gland. Due to such a diagnosis, bilateral mastectomy was recommended. The material obtained during the surgical procedure was sent for anatomopathological analysis. Microscopically, surgical margins infi ltration and a regional lymph node were verifi ed. The owner was advised of the need for complementary therapies and medical monitoring of the cat. However, there was no return. It is noteworthy that the animal’s physical and laboratory examinations showed no neoplasia in other regions, being the squamous cell carcinoma of the mammary gland considered primary. Discussion: The malignant mammary neoplasia genesis in feline species, in general, seems to be related to steroid hormones. The ovariectomized females are less likely to develop the disease when compared to intact cats, but there is no protective effect of surgery on those spayed after two years of age regarding the appearance of the neoplasia. Thus, at the time the reported patient was ovariectomized, this effect no longer occurred. The synthetic progestins regularly used to prevent estrus increase by three times the risk of breast carcinomas onset. In humans, there is no clear defi nition of the etiology and pathogenesis of mammary squamous cell carcinoma. However, it has been suggested its association with extreme forms of squamous metaplasia present in pre-existing mammary adenocarcinoma, besides cysts, chronic infl ammations, abscesses and mammary gland adenofi bromas. In a hypothetical way, this etiology could also be related to the feline mammary carcinoma, although, for the case at issue, the exogenous and endogenous hormonal infl uence should not be excluded. It has been reported that mammary squamous cell carcinomas in cats are classifi ed in grades II and III (ie, moderately and poorly differentiated, respectively). Thus, they are considered tumors with more unfavorable prognosis. However, the monitoring of the clinical course, in order to evaluate possible recurrence of the neoplasia and metastases to distant sites, was not possible as the animal under discussion did not return. The squamous cell carcinoma is the most common skin tumor in feline species, despite the primary location in the mammary gland. It is, therefore, important to differentiate squamous cell carcinoma originated in the breast from histological types derived from skin. The description of this special and rare feline mammary carcinoma is important due to its particular characteristics and potential for malignancy.