Influence of ridge type on mandibular distal extension removable partial denture.

The aim of this study was to use photoelastic models to analyze the distribution of stress caused by the incidence of loads on a mandibular distal extension removable partial denture, both on the abutment teeth and on differently shaped residual ridges: distal ascending, descending-ascending, horizontal and distal descending. The best type of retainer and location of the rest on the last abutment tooth were determined for the different types of ridge. Four models were made from photoelastic resin (PL-1 for the teeth and PL-2 for the alveolar ridge), one for each kind of ridge. For each model, 4 removable partial dentures (RPD) were made (16 RPD altogether): T-bar retainer and distal rest, T-bar retainer and mesial rest, circumferential retainer and distal rest, and circumferential retainer and mesial rest. The models were placed on a circular polariscope and a 100 N axial load (point load) was applied to premolars and molars of the RPD. The formation of photoelastic bands was photographed for qualitative analysis. Results showed that the horizontal ridge had better distribution of stress, while the distal descending ridge had greater concentration of stress. The circumferential retainer had greater areas of stress for all types of ridges except the horizontal ridge, where there was no influence related to retainer type. The distribution of stress was similar among the different types of ridges when the rest was mesial or distal to the last abutment tooth, except for the distal descending ridge, where there was greater concentration of stress when the rest was located distally to the last abutment tooth. Thus, it may be concluded that (1) the situation was least favorable for the distal descending ridge and most favorable for the horizontal ridge, (2) the T-bar retainer had more favorable stress distribution, except when the ridge was horizontal, in which case there was no influence in relation to the type of retainer, (3) the location of the rest showed similar behavior in all except the distal descending ridge.

Scanning electron microscopic evaluation of the root apex of mandibular premolars.

This aim of this study was to evaluate the root apex of mandibular premolars regarding the presence of main and accessory foramina. The root apexes from fifty extracted mandibular single-rooted premolars were examined by scanning electron microscopy (SEM). The apical openings had their diameter measured and were identified as main or accessory foramina. Double blinded and calibrated examiners analyzed the SEM photographs and classified the premolar roots into three types, based on the presence and size of the apical openings. Type I: roots with a single main apical foramen and no accessory foramina; type II: roots with a main foramen and one or more accessory foramina; type III: roots with accessory foramina only. For the first premolar, 16 roots were classified as type I (48.48%), 4 as type II (12.12%) and 13 as type III (39.40%). For the second premolars, 10 roots were classified as type I (58.83%), 3 as type II (17.65%) and 4 as type III (23.52%). The high incidence of roots with accessory foramina only (type III), mainly in the first premolar, warns of the need for caution during working length determination and apical debridement.

Cherubism: Clinical case and genetic standpoints

Cherubism is a rare non-neoplastic hereditary disease, characterized by bilateral bone enlargement of the jaws and is accompanied by inflammation and fibrosis in childhood. An increase in jaw size is noted, with maximum enlargement occurring within 2 years of onset in most cases. By age 7, the lesions become static or progress relatively slowly until puberty. During the late teens, the disease may undergo spontaneous involution. The present case show a patient with history of bilateral enlargement of the jaw with the triad of clinical, histological and radiological findings that helps in the final diagnosis of cherubism.

Calcium hydroxide intracanal dressing removal with different rotary instruments and irrigating solutions: A scanning electron microscopy study

This study evaluated the efficacy of 2 types of rotary instruments employed in association with sodium hypochlorite (NaOCl) or EDTA in removing calcium hydroxide (CH) residues from root canals dentin walls. Forty-two mandibular human incisors were instrumented with the ProTaper System up to F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA and filled with a CH intracanal dressing. After 7 days, the CH dressing was removed using 4 techniques: NiTi rotary instrument size 25, 0.06 taper (K3 Endo) and irrigation with 17% EDTA (Group 1), NiTi rotary F1 instrument (ProTaper) and irrigation with 17% EDTA (Group 2), NiTi rotary instrument size 25, 0.06 taper and irrigation with 2.5% NaOCl (Group 3) and NiTi rotary F1 instrument and irrigation with 2.5% NaOCl (Group 4). Two roots without intracanal dressing were used as negative controls. Teeth were evaluated by scanning electron microscopy, in the cervical and apical canal thirds. None of the techniques removed the CH dressing completely. In the apical and cervical thirds, F1 instrument was better than instrument size 25, 0.06 taper in removing CH residues (p<0.05), regardless of the final irrigating solution. No difference was found between the irrigating solutions in the groups of F1 instrument and of instrument size 25, 0.06 taper (p>0.05). The negative controls had no CH residues on the dentin walls. In conclusion, the ProTaper F1 instrument was better than K3 Endo instrument size 25, 0.06 taper in the removal of CH intracanal medication, regardless of irrigating solution used.

Expression of p53, Ki-67, and CD31 proteins in endometrial polyps of postmenopausal women treated with tamoxifen.

This study was undertaken to investigate the expression of p53, Ki-67, and CD31 proteins in endometrial polyps of postmenopausal women treated with tamoxifen (TAM). Postmenopausal women with endometrial polyps treated with TAM (n = 20), postmenopausal women with endometrial polyps without hormone use (n = 20), postmenopausal women with atrophic endometrium (n = 20), and postmenopausal women with endometrial adenocarcinoma (n = 20) were prospectively investigated. Tissue samples were immunohistochemically evaluated by monoclonal antibodies for p53, Ki-67, and CD31. The data were analyzed using the Student t test, analysis of variance, and χ2 to evaluate significant differences between the groups. The level of significance was set at P < 0.05. There was no difference in the expression of p53 between the groups (P = 0.067). The expression of Ki-67 was higher in the polyp samples from TAM-treated women compared with those from the women using no hormone (P = 0.0047) and those from the women with atrophic endometrium (P = 0.008). Samples from the women with endometrial cancer was associated with higher Ki-67 expression compared with the polyp samples from TAM-treated women (P = 0.004). The expression of CD31 was higher in the polyp samples of TAM-treated women compared with that of the samples from the women with atrophic endometrium (P < 0.001) and similar to the polyp samples from the women using no hormone (P = 0.319) and to the samples from the women with endometrial cancer (P = 0.418). The use of TAM in postmenopausal women might be associated with increased cellular proliferation in endometrial polyps without interfering angiogenesis or inactivation of tumor suppressor proteins.

A CAD/CAM flapless surgical technique and immediate prosthesis: A clinical report

Background: This article describes a clinical report with a new system for guided surgical treatment and immediate load prosthesis in the flapless surgical technique. Case report: Based on a computed tomography (CT) of a 64 - year-old edentulous patient, the cross sections were reformatted and used to construct a virtual planning of the implants and a guide template in Dental Slice. Six dental implants were placed in the maxilla and mandible using a Slice Guide System. Following a 30-month in maxilla and 24-month in mandible healing period, the clinical and radiographic evaluation and computed tomography (CT) showed good clinical stability. The Slice Guide System proved satisfactory for the Flapless Surgical Technique in dental implants.

Avaliação histológica e morfométrica do retalho axial oris angularis e da terapia por ondas de choque aplicados a defeito palpebral experimental em cães

Considering that the cutaneous flap can be affected by isquemic complications the extra corporeal shock wave therapy (ESWT) was described as rescue techniques. The present study was developed to analyze histological and with morfometry, twenty one skin samples treated or not with the shock wave therapy, obtained from flap's distal border, used in this study to repair eyelids' experimental defects in dogs. The flap with or without ESWT did not show any histological sign of inflammatory or atrophic alterations. Both group treated showed similar morphometrical characteristics. The ESWT with the protocol used in this study (2500 impulses at 0,15 mJ/mm 2) did not demonstrate significant clinical outcomes as a rescue technique when applied over the oris angularis flap, however results showed no signals of collateral deleterious effects.

Changes in facial morphology after adenotonsillectomy in mouth-breathing children

Background. Morphological and dentofacial alterations have been attributed to impaired respiratory function. Objective. To examine the influence of mouth breathing (MB) on children facial morphology before and after adenoidectomy or adenotonsillectomy. Methods. Thirty-three MB children who restored nasal breathing (NB) after surgery and 22 NB children were evaluated. Both groups were submitted to lateral cephalometry, at time 1 (T1) before and at time 2 (T2) 28months on average postoperatively. Results. Comparison between the MB and NB groups at T1 showed that mouth breathers had higher inclination of the mandibular plane; more obtuse gonial angle; dolichofacial morphology; and a decrease in the total and inferior posterior facial heights. Twenty-eight months after the MB surgical intervention, they still presented a dolichofacial morphologic pattern. During this period, MB altered the face growth direction and decreased their mandible plane inclination, with reduction in the SN.GoGn, PP.MP, SNGn, and ArGo.GoMe parameters as well as an increase in BaN.PtGn. Conclusion. After the MB rehabilitation, children between 3 and 6years old presented significant normalization in the mandibular growth direction, a decrease in the mandible inclination, and an increase in the posterior facial height. Instead, they still persisted with a dolichofacial pattern when compared with nasal breathers. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

Tracheostomy-dependent child with temporomandibular ankylosis and severe micrognathia treated by piezosurgery and distraction osteogenesis: Case report

Ankylosis of the temporomandibular joint in children is one the most difficult and complex conditions managed by oral and maxillofacial surgeons, and often leads to some facial deformity. Distraction osteogenesis of the mandible provides an excellent treatment for mandibular airway obstruction in children who do not respond to conservative measures, and allows for early removal of the tracheostomy. We report the case of a 1-year-old boy with severe micrognathia and temporomandibular ankylosis who was dependent on a tracheostomy; he was treated with piezosurgery and mandibular advancement by distraction osteogenesis. © 2010 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Marginal resection for treatment of mandibular osteomyelitis associated with osteopetrosis: Case report

Osteopetrosis (OP) is a rare hereditary disorder characterized by a dysfunction of the osteoclasts that impairs bone resorption, which together with the normal osteoblastic activity forms intense bone sclerosis with reduction of marrow. A common complication that arises, most frequently, as a result of tooth extraction is mandibular osteomyelitis. There is no consensus on the literature about the treatment of this infection in an osteopetrotic patient, therefore, the purpose of this paper is to report a case of marginal resection for treatment of mandibular osteomyelitis in an osteopetrotic patient and discuss relevant features of this procedure. © 2010 European Association for Cranio-Maxillo-Facial Surgery.

Influence of lateral excursion on vestibular cervical dental abfraction.

A study was performed to evaluate the influence of mandibular lateral excursion, group function and canine guidance on vestibular cervical dental abfraction (VCDA). Thirty-six individuals of both sexes, aged 20 to 45 years, with full natural dentition with at least one tooth with VCDA were selected at the San Marcos University Clinic. We evaluated number of teeth with VCDA per side (left and right), tooth type and lateral excursive movement (canine guidance or group function) affecting it. The results showed no statistical difference (p > 0.05). The tooth type most often showing VCDA was the first lower premolar, with 30.8% on the right side and 36.4% on the left. Moderate positive correlation was found between age and VCDA (R = 0.40). It is concluded that group function during lateral excursion may contribute to presence of VCDA.

Osteossarcoma mandibular em gato: Relato de Caso

The primary malignant bone tumors are uncommon in cats. Osteosarcoma is the most frequently observed in old animals. This tumors affects the appendicular skeleton, however the axial skeleton is also affected, but the bones of the head and pelvis frequent sites of injury. This paper reports a case of a cat with a history of progressive swelling in the left mandible, with follow-up period of four months. The presumptive diagnosis of osteopathy, signed by clinical and radiographic observations were confirmed by histopathology and there it is moderately productive osteoblastic osteosarcoma.

Drug-induced gingival overgrowth: A clinical and histopathological report

Gingival overgrowth is a significant problem faced by periodontists and is particularly associated with the use of certain drugs such as nifedipine, a high-specificity calcium channel blocker used for the treatment and prophylaxis of certain cardiovascular diseases. Development of gingival overgrowth is characterized by increased collagen in gingival tissue. In general is asymptomatic, at times associated with spontaneous bleeding and ulceration and can promote aesthetic changes and compromise hygiene habits and mastication of the patient. The severity of the symptoms is associated with the presence of risk factors such association with other drugs. This paper aims to present a case report of a patient with generalized gingival overgrowth, with more severe characteristics in the anterior mandible induced by chronic use of nifedipine who underwent basic non-surgical periodontal treatment including supra and subgingival scaling and root planning in both jaws associated with rigorous oral hygiene instructions and surgical therapy in the anterior mandible, the most affected area, to remove the excess of gingival tissue. Nifedipine was replaced by the patient cardiologist to propanolol hydrochloride (40 mg/kg) in an attempt to minimize unwanted side effects. After 6 month follow-up, no recurrence was observed, oral hygiene had improved and the patient had clinical periodontal health and esthetic satisfaction.

Peripheral calcifying cystic odontogenic tumour of the maxillary gingiva

Background: Odontogenic tumors are lesions that are derived from remnants of the components of the developing tooth germ. The calcifying cystic odontogenic tumor or calcifying odontogenic cyst is a benign cystic neoplasm of odontogenic origin that is characterized by an ameloblastoma-like epithelium and ghost cells. Calcifying cystic odontogenic tumor may be centrally or peripherally located, and its ghost cells may exhibit calcification, as first described by Gorlin in 1962. Most peripheral calcifying cystic odontogenic tumors are located in the anterior gingiva of the mandible or maxilla. Case presentation. Authors report a rare case of a peripheral calcifying cystic odontogenic tumor of the maxillary gingiva. A 39-year-old male patient presented with a fibrous mass on the attached buccal gingiva of the upper left cuspid teeth. It was 0.7-cm-diameter, painless and it was clinically diagnosed as a peripheral ossifying fibroma. After an excisional biopsy, the diagnosis was peripheric calcifying cystic odontogenic tumor. The patient was monitored for five years following the excision, and no recurrence was detected. Conclusions: All biopsy material must be sent for histological examination. If the histological examination of gingival lesions with innocuous appearance is not performed, the frequency of peripheral calcifying cystic odontogenic tumor and other peripheral odontogenic tumors may be underestimated. © 2012 Lima et al.; licensee BioMed Central Ltd.

Compared morphology of the immatures of males of two urban ant species of camponotus

The immatures of males of two species of Camponotus ants (Hymenoptera: Formicidae) are described and compared by light and electron microscopy. The numbers of larval instars were determined: Camponotus rufipes Fabricius (Hymenoptera: Formicidae) have four instars; and Camponotus vittatus Forel have three. Male larvae of the two species are similar to previously described Camponotus larvae, sharing the following traits: basic shape of body and mandible, presence of 'chiloscleres', 'praesaepium' (some specimens), labial pseudopalps, and ten pairs of spiracles. However, larvae of the two species can be separated by bodily dimensions and based on their hair number and types. Worker larvae of C. vittatus previously described are extensively similar to male larvae, with only a few inconspicuous differences that may result from intraspecific variation or sexual differences.