Stress evaluation of different implant lengths on atrophic edentulous mandibles with fixed full-arch implant-supported prosthesis: a finite element analysis.

Finite element analysis was used to compare the effect of different implant lengths on atrophic mandible with full-arch fixed prostheses. Four models were constructed with different implant lengths: 4, 6, 8 and 10 mm. A 100-N occlusal load was applied. The stress at the bone level, implant, and prosthetic components were obtained. Similar behavior was observed for all groups, except for 4 mm, which showed more discrepant values ​​for all prosthetic components. Although longer implants presented better biomechanical behavior, the 4 mm implant seems to be a viable alternative for severely atrophic mandibles, however, further studies need to be carried out.

Description of the periodontal pocket in preclinical models: limitations and considerations.

Establishment of periodontal health and regeneration of the lost periodontal tissues are always the ultimate goal of periodontal treatment. The development of new therapeutic approaches raises the necessity for appropriate experimental models that present periodontal structures and healing capability comparable to humans. Preclinical research and extrapolation of the data to human conditions remains a stage of great importance before the clinical application of the new biomaterials and techniques. Periodontal pockets/defects in preclinical models can be induced experimentally through acute or chronic or a combination of both (induced) modalities. The features of the created defects and those of humans vary greatly mostly due to the nature of the periodontal disease. This is an important point to take into account, since it is well recognized that the potential of periodontal therapy may be dependent on both the biological background and the defect morphology. This review provides insight into the commonly used preclinical models for the reproduction of the periodontal pocket and discusses the advantages and disadvantages of each model in terms of similarity to human conditions, standardization and reproducibility.

Polymorphisms of Il-10 (-1082) and RANKL (-438) Genes and the Failure of Dental Implants.

Background. Genetic polymorphisms in certain cytokines and chemokines have been investigated to understand why some individuals display implant flaws despite having few risk factors at the time of implant. Purpose. To investigate the association of genetic polymorphisms in interleukin- (IL-) 10 [-1082 region (A/G)] and RANKL [-438 region (A/G)] with the failure of dental implants. Materials and Methods. This study included 90 partially edentulous male and female patients who were rehabilitated with a total of 245 Straumann dental implants. An implant was considered a failure if any of the following occurred: mobility, persistent subjective complaint, recurrent peri-implant infection with suppuration, continuous radiolucency around the implant, probing depth ≥ 5 mm, and bleeding on probing. Buccal mucosal cells were collected for analysis of RANKL438 and IL-10. Results. The implant success rate in this population was 34.4%. The mutant allele (G) in RANKL had an incidence of 52.3% and mutant allele (A) in IL-10 was observed in 37.8%. No statistically significant difference was detected between the failure of the implant and the genotypes and allelic frequencies. Conclusion. No association was detected between the genetic polymorphisms of RANKL (-438) and IL-10 (-1082) and the failure of dental implants in the population studied.

Nevoid Basal Cell Carcinoma Syndrome: A Long-Term Study in a Family.

We present a family case series with 10 individuals having nevoid basal cell carcinoma syndrome (NBCCS) with a 10-year follow-up. All articles published in the literature between 1967 and 2011 on familial Gorlin-Goltz syndrome in any language were surveyed to determine the mapping of cases per country of occurrence of this disease. All patients in the present series were presented with calcification of the falx cerebri, mild hypertelorism, and frontal bossing. Odontogenic keratocystic tumors, palmar and plantar pits, and multiple basal cell carcinomas occurred in 90, 40, and 20%, respectively, of the patients. One of the patients died of skin cancer. Diagnosis of odontogenic keratocyst tumors was confirmed by histopathological examination. NBCCS is a rare autosomal dominant cancer predisposition syndrome; it is important to recognize it when a patient has multiple odontogenic keratocyst tumors because life-long monitoring is essential for patient management.

Treatment of condylar fractures with an intraoral approach using an angulated screwdriver: results of a multicentre study.

BACKGROUND: This multicentre study aimed to investigate long-term radiographic and functional results following the treatment of condylar fractures using an angulated screwdriver system and open rigid internal fixation with an intraoral surgical approach. METHODS: Twenty-nine patients with a total of 32 condylar fractures were evaluated. The patients were investigated prospectively based on the following variables: age, sex, aetiology, side, location and classification of the fracture, degree of displacement, associated fractures, surgical approach, oral health status, type of osteosynthesis plate, duration of surgery, mouth-opening, complications, and duration of follow-up. RESULTS: The fractures were classified as subcondylar (n = 25) or condylar neck (n = 7). Mean patient age was 36.38 ± 16.60 years. The median duration of postoperative follow-up was 24.39 ± 13.94 months. No joint noise, weakness of the facial nerve, joint pain, or muscle pain was observed. An additional retromandibular approach was necessary to enable the treatment of one subcondylar fracture with medial displacement. CONCLUSION: Subcondylar or condylar neck fractures with medial or lateral displacement can be treated using an intraoral approach with satisfactory results with the advantages of the absence of visible scarring, the avoidance of facial nerve injury, and the ability to obtain rapid access to the fracture.

Ameloblastoma in the Northeast region of Brazil: A review of 112 cases.

CONTEXT: Ameloblastomas are benign tumors of the jaws with locally invasive capacity. AIM: The aim of this study was to review 112 cases of ameloblastoma seen over an 18-year period (1992-2009) at the Pernambuco Dental School, University of Pernambuco and at Federal University of Sergipe, in the northeast region of Brazil. MATERIALS AND METHODS: THE FOLLOWING DATA WERE SELECTED FOR ANALYSIS: age, gender, race, site distribution, radiographic appearance, association with an impacted tooth, size, presence of symptoms, clinicopathologic subtypes and recurrence. SETTINGS AND DESIGN: In this retrospective study, Pearson's χ(2) test and t-test were employed. The critical level of significance was set at P < 0.05. RESULTS: The mean age of the patients at presentation was 35.1 ± 16.8 years with a slight female preference. The peak prevalence was in the 11- to 20-year age group and declined with increasing age. Total 75 patients were black and 37 were white, for a 2:1 black: white ratio. The location of the ameloblastomas showed a marked predominance in the mandible (84.8%) and 69% of the cases presented with a multilocular radiographic appearance. The tumor was associated with an embedded tooth in 14 cases (12.7%): nine unilocular and five multilocular ameloblastomas. The maximum radiological extension of the lesions on panoramic radiographs was 0.5-20 cm (mean ± SD: 5.2 ± 3.3 cm) and most cases were symptom-free (75.9%). Solid/multicystic ameloblastoma was the most common clinicopathologic subtype. There was an association between the clinicopathologic subtypes and radiographic appearance (P < 0.001). Recurrence was observed in 13.3% of cases. CONCLUSION: We propose that racial factors may have strong influence on the incidence of ameloblastomas in the northeast region of Brazil, since most people have African descent. Data related to gender, location, radiographic appearance, size, symptoms, clinicopathologic subtypes and recurrence were similar to previous studies conducted in various parts of the world.

A systematic review on the critical size defect model.

OBJECTIVES: To systematically review the literature data regarding the critical size defect (CSD) in adult rat calvaria and to determine which defect dimensions could be considered as being critical size. MATERIAL AND METHODS: A literature search was conducted at Ovid Medline and Embase up to July 2012. Studies presenting with at least one of the primary outcomes of interest (number of defects with complete closure and the percentage of new bone formation (%NBF) in rat calvaria) were included. Screening, data extraction and quality assessment were conducted independently and in duplicate. RESULTS: From 1461 citations, 257 full-text papers were screened and 61 papers were included in the analysis. Fourteen of 937 evaluated defects presented complete closure. Only 7 and 6 untreated sites in 5.0- and 6.0-mm-diameter defects, respectively, showed complete closure. A great variability among the preclinical models was seen, and the meta-analysis result showed a high heterogeneity regarding the mean %NBF. The mean %NBF according to the defect dimension was as follows: 18.29% and 21.44% for 5.0 mm central single defects at 1 and 3 months, respectively; 17.55%, 20.24% and 22.65% for 5.0 mm bilateral defects; 9.81%, 12.56% and 7.96% for 8.0 mm single defect; 11.18%, 9.48% and 26.24% for 9.0 mm single defects at 1, 2 and 3 months, respectively. CONCLUSION: Calvarial defects with a diameter of 5.0 mm could be considered as a CSD. However, there is a necessity for further standardization of the rat calvaria model to enable more accurate comparison among future studies.

Management of subcondylar fracture by intraoral approach.

Condylar fracture osteosynthesis is nowadays commonly practiced, but only a few studies report the intraoral approach with angulated devices. Subcondylar fractures with little or lateral displacement can be treated using an intraoral approach with satisfactory results. The advantages of this approach are the absence of visible scars, the avoidance of facial nerve injury inherent to the extraoral approach, quick access to the fracture, and a reduced risk of infection. The authors report a case of subcondylar fracture treated through an intraoral approach. Despite the considerable lateral dislocation of the condyle, treatment consisted of the reduction of the fracture and osteosynthesis with a trapezoidal condylar plate using an intraoral surgical approach.

Comparative finite element analysis of the biomechanical stability of 2.0 fixation plates in atrophic mandibular fractures.

PURPOSE: The objective of the present study was to conduct a computational, laboratory-based comparison of the biomechanical stability of 2.0 fixation locking plates with different profiles in Class III atrophic mandibular fractures using 3-dimensional finite element analysis. MATERIALS AND METHODS: Three-dimensional finite element models simulating Class III atrophic mandibular fractures were constructed. The models were divided into 4 groups according to plate thickness (1.0, 1.5, 2.0, and 2.5 mm). Fractures were simulated in left mandibular bodies, and 3 locking screws were used on each side of each fracture for fixation. Bite forces of approximately 63 N were simulated in the incisor and molar regions of the mandibles in finite element models. RESULTS: The level of compressive strain on the bone around the screw was within the physiological limit. No significant difference was observed in the displacement of bone segments in the fracture region. Von Mises stress was higher during simulated bites in the molar region for plates with thicknesses of 1.0 mm. Plate tension values were below the level required for permanent deformation or fracture in all models. The 2.5-mm-thick plate presented better biomechanical performance than all other plates. The 2.0-mm-thick plate also showed satisfactory results and adequate safety limits. CONCLUSION: Large-profile (2.0-mm-thick) locking plates showed better biomechanical performance than did 1.0- and 1.5-mm-thick plates and can be considered an alternative reconstruction plate for the treatment of Class III atrophic mandibular fractures.

Hemodynamic changes comparing lidocaine HCl with epinephrine and articaine HCl with epinephrine.

BACKGROUND: The aim of the present study was to analyze hemodynamic changes after the administration of either 2% lidocaine with epinephrine 1:100,000 (L100) or 4% articaine with epinephrine 1:200,000 (A200) in the surgical removal of symmetrically positioned lower third molars. METHODS: A prospective, randomized, double-blind, clinical trial was carried out involving 43 patients. Each patient underwent 2 surgeries on different occasions-one under local anesthesia with L100 and the other with A200. The following parameters were assessed at 4 different times: systolic, diastolic, and mean blood pressure; heart rate; oxygen saturation; rate pressure product (RPP); and pressure rate quotient (PRQ). RESULTS: No hypertensive peak was observed in systolic, diastolic, and mean blood pressure at any evaluation time. Moreover, the type of anesthetic solution did not affect diastolic blood pressure, oxygen saturation or PRQ during the surgeries. Statistically significant differences between groups were detected with regard to heart rate and RPP (P < 0.05). CONCLUSIONS: The epinephrine concentration (1:100,000 or 1:200,000) and local anesthetic solutions used (2% lidocaine or 4% articaine) influenced hemodynamic parameters without perceptible clinical changes in healthy patients undergoing lower third molar removal.

Hemodynamic changes comparing 2% lidocaine and 4% articaine with epinephrine 1: 100,000 in lower third molar surgery.

BACKGROUND: An increase in blood pressure during dental treatment has been investigated with regard to potential medical risks since previous studies suggest that dental procedures may cause stress to the patient and, consequently, the cardiovascular system. The aim of the present study was to analyze hemodynamic changes following the administration of either 2% lidocaine (L100) or 4% articaine (A100) (both with epinephrine 1:100,000) in the surgical removal of symmetrically positioned lower third molars. METHODS: A prospective, randomized, double-blind, clinical trial was carried out involving 47 patients. Each patient underwent 1 surgery at each of 2 appointments--one under local anesthesia with L100 and the other with A100. The following parameters were assessed at 4 different times: systolic, diastolic, and mean blood pressure; heart rate; oxygen saturation; rate pressure product; and pressure rate quotient. RESULTS: No hypertensive peak was observed in systolic, diastolic, and mean blood pressure at any evaluation time. Moreover, the type of anesthetic solution did not affect diastolic blood pressure, heart rate, or oxygen saturation during the surgeries. The pressure rate quotient was the only parameter to exhibit statistically significant differences between groups at different evaluation times (P < 0.05). CONCLUSIONS: The hemodynamic parameters evaluated in third molar surgery with 2% lidocaine and 4% articaine (both with epinephrine 1:100,000) did not show significant differences.

Avulsion of globe following maxillofacial trauma.

Avulsion of the eye globe is a rare condition that is unexpected in maxillofacial trauma and results from severe trauma to the orbit and face. A search of the literature reveals very few reported cases. The present article reports a case of this singular, challenging condition and comments on several other related causes, pathophysiology mechanisms, risks, complications, and management.

Foreign body ingestion during dental implant procedures.

Two cases of swallowing of foreign material related to dental implants during dental practice are described. A conservative approach by clinical-radiographic follow-up was performed in both cases; however, one of the patients required colonoscopy under general anesthesia for the removal of the impacted foreign body from the intestinal region. These complications not only have associated economic cost but also carry the risk of malpractice litigation against the professional; thus, the surgeon was responsible for all the costs of hospital and surgery management of this case. Details of the clinical signs, radiographic examinations, type of treatment, and follow-up are presented.

Fracture of the coronoid process, sphenoid bone, zygoma, and zygomatic arch after a firearm injury.

A rare case of fracture of the coronoid process, sphenoid bone, zygoma, and zygomatic arch caused by a firearm is described. A 25-year-old man was hit in the face with a bullet, resulting in restricted mouth opening, difficulty chewing, and pain when opening the mouth. The clinical examination revealed a perforating wound in the right parotid region. A computed tomographic scan revealed a comminuted fracture of the left coronoid process with the bullet stopping in the intact left coronoid process. Treatment was bilateral coronoidectomy associated with speech therapy and was successful. Details of the clinical signs, computed tomography, treatment, and follow-up are presented.

Tratamento cirúrgico das fraturas subcondilianas por via intrabucal: relato da técnica / Surgical treatment of subcondylar fracture through intra-oral approach: techinical note

As fraturas subcondilianas ainda são um tópico bastante controverso na literatura devido à falta de evidência científica quanto ao melhor método de tratamento. Em relação aos acessos cirúrgicos, o retromandibular e o pré-auricular são os mais utilizados. Com o desenvolvimento de instrumentos, como afastadores específicos e perfuradores em 900 (contra-ângulo), a fixação de placas na região posterior de mandíbula tornou-se viável por via intrabucal através de visão direta. Essa abordagem apresenta vantagens, como a ausência de cicatrizes visíveis e da possibilidade de lesão do nervo facial, inerentes à abordagem extrabucal, além do acesso rápido à fratura e do menor risco de infecção. A limitação do campo cirúrgico e a dificuldade da redução de fraturas com deslocamento medial são as principais desvantagens do acesso intrabucal, sendo estas, geralmente, tratadas pelos acessos extrabucais, o qual propicia um campo cirúrgico mais direto. O objetivo deste trabalho é descrever o tratamento cirúrgico das fraturas subcondilianas por via intrabucal.

Subcondylar fractures is still a very controversial topic in the literature for the lack of scientific evidence concerning the best method of treatment. Regarding the surgical approaches, the pre-auricular and retromandibular are the most used. With the development of instruments such as specific retractors and 900screwdriver, fixation of the plate at the posterior mandibular region became possible by means of intra-oral direct vision. This approach has advantages as the absence of visible scars and the possibility of facial nerve injury inherent in the extra-oral approach, as well as quick access to fracture and reduced risk of infection. The limitation of the surgical field and the difficulty of reducing fractures with medial displacement are the main disadvantages of intra-oral access, which are often treated by extra-oral access, which provides a more direct surgical field. The aim of this study is to report the treatment ok subcondylarfracturesthrough intra-oral approach.

Alterações do processo de reparo do tecido conjuntivo na região peri-implantar / Cicatrization alterations of connective tissue in peri-implant region

Devido a sua excelente biocompatibilidade, baixa condutividade térmica e alta resistência, o titânio passou a ser empregado na Odontologia sob a forma de implantes, com a capacidade de osseointegração, viabilizando, assim, a substituição de elementos dentários perdidos. O desafio atual no tratamento com implantes reside na habilidade de se detectarem indivíduos de risco tanto para a perda precoce (falha em se obter a osseointegração) quanto para a tardia (falha ocorrida após a osseointegração). A interação de fatores intrínsecos e extrínsecos no sítio ósseo lesado determina o caminho da diferenciação de fonte de células mesenquimais, controlando os monócitos, células-gigantes do tipo corpo estranho e células inflamatórias do tecido conjuntivo, estimulados por produtos de degradação da matriz, inviáveis para crescer e repovoar a área do implante do osso descalcificado. O objetivo do presente trabalho foi o de realizar uma revisão da literatura acerca das principais alterações do reparo do tecido conjuntivo peri-implantar durante o processo de osseointegração dos implantes dentais.

Due to its excellent biocompatibility, low thermal conductivity and high strength, titanium is now employed in the form of dental implants, with the ability to osseointegration thus allowing the replacement of lost dental elements. The current challenge in the treatment with implants is the ability to detect individuals at risk for losing both early (failure to get the osseointegration) and later (failure occurred after osseointegration). The interaction of intrinsic and extrinsic factors in the injured bone site determines the path of the source of mesenchymal cells' differentiation, controlling the monocytes, giant cells of foreign body, and inflammatory cells, connective tissue stimulated by degradation products of the matrix, not viable for grow and repopulate the area of the bone decalcification implantation. The objective of this study was to review the literature about the major changes in the repair of connective tissue periimplantar during osseointegration of dental implants.

A new approach for reconstruction of a severely atrophic mandible.

PURPOSE: The purpose of this study is to report a case of a patient with a severely atrophic mandible (less than 5 mm) who was treated without bone graft using short implants and internal rigid fixation. PATIENT AND METHODS: A 61-year-old woman was referred to a private clinic in the city of Recife (Brazil) with a severely resorbed mandible (less than 5 mm). The patient reported a history of nearly 15 years of complete edentulism and consecutive treatment failures. Cone beam tomography was performed and severe atrophy was confirmed, revealing total bilateral exposed inferior alveolar nerves. There was a high risk of pathologic mandible fracture, since bone density in critical areas was very low. Treatment of choice was the placement of 4 Shorty (3.75 x 5.5 mm) implants (Nobel Biocare, Göteborg, Sweden) at the symphysis for immediate functional reasons and a 2.0-mm large profile Unilock bone plate (Synthes Maxillofacial, Paoli, PA) to reinforce the mandible. A rapid prototype model was made to help precontour the plate, enabling the insertion of the plate through the transoral approach. RESULTS: A week after surgery, a Brånemark prosthesis protocol was performed and the patient was satisfied with the result. At 29 months after surgery, the patient was still satisfied and had excellent function without complications. CONCLUSIONS: Because of the reported advances in implantology and internal rigid fixation, more patients would be able to improve their severe dental condition without the use of more invasive techniques.