Pedro Antonio González Hernández

Time interval after radiotherapy and dental implant failure: systematic review of observational studies and meta-analysis.

BACKGROUND Typically, dental implants are placed in irradiated bone after a delay that exceeds 6 months, but it is not known whether longer delays are beneficial. PURPOSE The purpose of the study is to review the literature comparing the failure rate of dental implants placed in irradiated bone between 6 and 12 months and after 12 months from the cessation of radiotherapy. MATERIALS AND METHODS Four electronic databases were searched for articles published until February 2013 without language restriction: Lilacs, Medline, Scopus, and the Cochrane Central Register of Controlled Trials. Two reviewers independently assessed the eligibility criteria and extracted data. Fixed effect meta-analysis was performed. RESULTS Overall, 3,749 observational studies were identified. After the screening of titles and abstracts, 236 publications were selected, and 10 were included in the final analysis. The pooled relative risk (RR) of failure was RRpooled  = 1.34 (95% confidence interval [CI]: 1.01-1.79), higher in individuals who had dental implants installed between 6 and 12 months after receiving radiotherapy. I(2) indicated nearly 21% heterogeneity (p = .25). Eggers test indicated no evidence of publication bias (p = .62); however, the removal of one study significantly affected the overall RR (RRpooled  = 1.08, 95% CI: 0.77-1.52). CONCLUSIONS Placing implants in bone within a period shorter than 12 months after radiotherapy may result in a higher risk of failure; however, additional evidence from clinical trials is needed to verify this risk.

Calcium phosphate cement in orbital reconstructions.

Abstract Treatment of facial trauma sequelae is a complex and challenging process. There is still controversy over suitable materials for orbital wall reconstruction. This study evaluated calcium phosphate cement (CPC) implants manufactured by rapid prototyping in the repair of orbital wall defects secondary to trauma. Computed tomographic scans of 5 patients were used for surgery planning and production of CPC implants. Implants were used to restore orbital wall anatomy, ocular alignment, and facial contour. Benefits resulting from the use of implants, such as a reduced operating time, patient response to biomaterial implantation, biomaterial integrity and stability, and patient satisfaction with treatment, were analyzed qualitatively. Our results suggest that CPC is an effective and safe material for orbital reconstruction because of its biocompatibility and easy production and placement.

Alpha-tricalcium phosphate cement in the reconstruction of bone defects in rats

PURPOSE To evaluate the ability of a mixture of α-TCP and autogenous bone (AB) vs. α-TCP alone and AB alone to promote new bone formation and tissue repair in bone defects. METHODS Bone defects surgically created in 15 male Wistar rats were divided into four groups: Group I (AB), Group II (α-TCP), Group III (α-TCP+AB assessed by light microscopy), and Group IV (α-TCP+AB assessed by scanning electron microscopy). Bone repair findings were assessed at 30, 60, and 120 days postoperatively. RESULTS The histological findings obtained in Groups I (p=0.459), II (p=0.368), and III (p=0.459) and at 30 days (p=0.717), 60 days (p=0.717), and 120 days (p=0.779) did not show statistically significant differences. Scanning electron microscopy revealed direct contact between the α-TCP+AB implant and the bone tissue at 120 days. CONCLUSION The α-TCP implant is effective alternative bone substitutes for the treatment of critical size bone defects.

Effect of Surface Roughness and Low-Level Laser Therapy on Removal Torque of Implants Placed in Rat Femurs

The present study measured removal torque and bone-implant interface resistance of machined implants, acid-etched implants, or machined implants irradiated around the implant area with infrared low-level laser therapy (LLLT; 830 nm) immediately after surgery. There were statistically significant differences between Groups A (control) and B (rough surface) (P = .03). Implants with a rough surface seem to add resistance to the bone-implant interface compared with smooth titanium implants or implants treated with LLLT.

In vitro study of a modified sagittal split osteotomy fixation technique of the mandible: a mechanical test

This study was performed to evaluate the compressive mechanical strength of rigid internal fixation (RIF) using 1.5-mm L-shaped plates fixed with monocortical screws in sagittal split osteotomy (SSO). Thirty synthetic hemimandibles, which had all undergone a 5-mm advancement, were divided into three groups: three 12-mm bicortical titanium screws were placed in an inverted L pattern in group A; one straight 2.0-mm system spaced titanium plate fixed with four 5-mm monocortical screws was used in group B; two 1.5-mm system L-shaped titanium plates, each fixed with four 5-mm monocortical screws, were used in group C. The models were subjected to compressive and progressive mechanical tests with forces applied in the area between the second premolar and first molar to verify resistance in Newtons (N). A displacement speed of 1mm/min was applied, with a maximum 10mm displacement of the distal segment or until disruption of the fixation. The deformity and/or eventual rupture of the plates were evaluated, and consequently their technical stability was determined. The results showed that the modified fixation technique tested in this study on synthetic mandibles resulted in adequate stability and superior mechanical behaviour compared to simulated osteosynthesis with the use of a straight 2.0-mm titanium plate.

Evaluation of 1211 Third Molars Positions According to the Classification of Winter, Pell & Gregory

Panoramic radiographs are important for the evaluation and classification of the third molars position, allowing the diagnosis and planning of extraction. The objective of this study is to evaluate upper and lower third molars positions in panoramic radiographs with the classification methods proposed by Pell and Gregory (1933) and Winter (1926) and the subsequent comparison of results with other authors. Panoramic radiographs of 310 patients were analyzed, 197 female and 113 male, totaling 1,211 third molars. In relation to the upper third molars, the most prevalent positions were: angle compared to the long axis of the second molar of Distoangular form (53.23 %) and the depth of impaction as Class C (48.25 %). In the lower third molars, the most prevalent positions were: angle to the long axis of the second molar in Mesioangular classification (52.96 %), the depth of impaction was B (46.54 %) and the tooth relationship with the mandibular ramus was identified as class I (55.26 %). These results provide information that can be utilized in predicting third molar development in terms of impaction or eruption, assisting dental surgeons in making decisions regarding surgical planning and treatment.

Surgical Treatment of Condylar Hyperplasia Associated with Dentofacial Deformity: Low Condylectomy, Articular Disc Repositioning, and Orthognathic Surgery

Debido a la complejidad del tratamiento de la hiperplasia condilar asociada con deformidades dentofaciales y sus complicaciones, si no se trata, el cirujano debe estar alerta ante estos factores en el momento de la planificacion quirurgica para adaptar la terapia optima para cada paciente. Este caso describe un paciente con hiperplasia condilar derecha asociada con la deformidad dentofacial que fue tratado quirurgicamente con condilectomia baja, reposicionamiento y anclaje del disco articular, y la cirugia ortognatica, concomitantemente, con resultados estables, oclusion satisfactoria y armonia facial.

Profilaxia antibiótica de infecção pós-operatória nos períodos pré e pós-operatórios em cirurgia de terceiros molares

O uso rotineiro de profilaxia antibiotica em cirurgia para exodontia de terceiros molares e controverso. O objetivo deste trabalho foi analisar a conduta farmacologica de cirurgioes-dentistas que realizam este tipo de extracao dentaria em relacao a profilaxia de infeccoes pos-operatorias, comparando os dados a conduta dos professores das disciplinas de Cirurgia Bucomaxilofacial do curso de Odontologia da Universidade Luterana do Brasil, Canoas/RS. Para tanto, foi aplicado um questionario a 60 profissionais com o intuito de verificar os criterios de indicacao de profilaxia antibiotica para infeccoes pos-operatorias, posologia farmacologica e associacao com controle quimico do biofilme bacteriano, relacionando essas variaveis ao curso de origem e tempo de formado do profissional. Conclui-se que a maioria dos entrevistados indica profilaxia para infeccoes pos-operatorias, entretanto nao segue um protocolo definido sustentado em evidencias cientificas.