Bone healing with an in situ-formed bioresorbable polyethylene glycol hydrogel membrane in rabbit calvarial defects.

OBJECTIVES: The aims of this study were to test whether or not the application of an in situ-formed synthetic polyethylene glycol hydrogel (PEG) used as a biodegradable membrane for guided bone regeneration with a variety of graft materials and ambient oxygen or hyperbaric oxygen (HBO) environments would result in enhanced bone regeneration, and to observe the histologic and histomorphometric aspects of bone healing of the calvarial defects with and without a PEG membrane. STUDY DESIGN: Thirty adult, skeletally mature, male New Zealand white rabbits were randomly divided into 3 groups of 10 animals each. Bilateral 15-mm-diameter critical-size defects were created in the parietal bones of each animal. Group 1 served as a control with unfilled bilateral calvarial defects, group 2 had bilateral calvarial defects filled with morcelized autogenous calvarial bone, and group 3 had bilateral calvarial defects filled with a biphasic calcium phosphate ceramic. One of the calvarial defects was randomly protected with a PEG resorbable liquid membrane in each animal. Five animals from each group underwent a course of HBO treatment (2.4 ATA 100% oxygen for 90 minutes 5 days a week for 4 weeks) and the other 5 served as control and did not receive any supplemental oxygen (normobaric). The animals were killed 6 weeks after their surgery, and their parietal bones were harvested. The specimens were analyzed with microscopic computerized tomography (microCT) scans and histomorphometrics. RESULTS: The unfilled normobaric control bony defects did not heal, proving the critical-size nature of these defects. The presence of autogenous bone or bone ceramic in the defects increased the bone volume fraction and bone mineral density of the defects (P < .001). The presence of a membrane in the ungrafted and autogenous bone grafted defects resulted in a decrease in the corrected bone volume fraction (P = .002) but not in the bone ceramic grafted defects (P = .580). Bony healing of defects where the membrane was unsupported was compromised; the membrane did not maintain the desired bone regeneration volume with the unfilled and autogenous bone grafted groups. The PEG resorbable liquid membrane worked best with the bone ceramic material. HBO did not ameliorate the healing of the autogenous bone graft or ceramic filled defects in the 6-week time period of this study. CONCLUSIONS: Although the PEG resorbable liquid membrane is easy to use and forms an occlusive layer, caution is recommended when using the membrane over an unsupported defect. HBO did not ameliorate bony healing with the membrane at the early 6-week time point. The authors recommend future assessment with HBO at the 12-week time point.

Clindamicina para el tratamiento de infecciones dentales / Clindamycin for the treatment of dental infections

La clindamicina es un antibiótico de amplio espectro con actividad contra los aerobios grampositivos y una extensa gama de bacterias anaerobias, entre ellas los patógenos productores de betalactamasa. Los estudios in vitro e in vivo han demostrado que este fármaco alcanza una concentración elevada en el punto de infección, reduce la virulencia de las bacterias y refuerza las actividades fagocíticas de los linfocitos inmunitarios del huésped. La clindamicina por vía oral se absorbe con rapidez y eficacia, y su concentración permanece por encima de la concentración inhibidora mínima de la mayoría de los organismos por lo menos durante 6 horas. En este análisis, presentaremos pruebas de la eficacia e inocuidad de la clindamicina en el tratamiento de las infecciones odontogénicas con datos de estudios preclínicos y clínicos, los cuales avalan la aplicación general de este antibiótico como antiinfeccioso en el campo de la odontología.

Clindamycin is an antibiotic of wide range of action with a great activity against aerobic gram-positive germs and a broad spectrum of anaerobic bacteria, among which we can find the pathogenic agents that produce Beta-lactamase. The in vitro and in vivo have shown that this medicine reaches a high concentration at the infection point, reduces the bacteria virulence, and strengthens the phagocytic activity of the immunizing lymphocyte of the host. Clindamycin through oral ingestion is absorbed very quickly and effectively, and its concentration remains the same above the minimum inhibitory concentration of most of the organisms at least for six hours. In this analysis, we will introduce some proofs about the effectiveness and innocuousness of clindamycin in the treatment of odontogenic infections. This data is based upon clinical and pre-clinical studies that support the general use of this mentioned antibiotic as an anti-infectious agent in the field of odontology.

Patient evaluation of outcomes of external rhinoplasty for unilateral cleft lip and palate.

Thirty-five patients (range 16-59 years) with cleft-lip nasal deformity treated by external rhinoplasty were evaluated for satisfaction and perception of outcomes. Treatment involved alar base relocation and augmentation of the asymmetric nasal tip with auricular cartilage grafts. The patients completed a satisfaction survey and interview at the 2-year follow-up visit. A visual analogue scale (VAS) numbered 0-10 was also used by the patients to grade outcome compared to preoperative appearance at 4 anatomic sites. Prior to surgery, the nasal tip was perceived as being most deformed (15/35), followed by alar position (12/35) and nasal apertures (8/35). The site on the nose most improved by surgery was the tip (15), followed by alar position (10), symmetry of nostrils (6) and dorsum (4). The highest VAS score was for the tip (8.32), followed by alar position (7.59), dorsum (7.41) and symmetry of nostrils (6.73). No patients suffered long-term pain for more than 2 months following surgery. All patients were prepared to undergo such procedure for a second time, if necessary. The unilateral cleft-lip nasal deformity can be improved in the eyes of the patient, using the combination of external rhinoplasty with alar base relocation, where necessary, and auricular cartilage augmentation of the nasal tip.

[Bioabsorbable osteofixation devices]. / Les matériels d'ostéosynthèse résorbables.

There is continued interest in the development of new biomaterials. The application of new implantable biomaterials requires intense research and thorough evaluation. Much time and effort has been required to overcome the risks and problems associated with the bioabsorbable devices. For surgical bone fixation, these materials were investigated since the 1960's. Different polymer properties were explored to ensure adequate strength and biocompatibility. High-molecular-weight bioabsorbable polymers were initially used, followed by addition of reinforcement materials. The most recent materials are self-reinforced, small yet strong devices. The newer generations contain bioactive substances such as antibiotics and growth factors. Bioabsorbable materials are constantly changing as we try to adopt the principles of tissue engineering. Surgeons are using new techniques to exploit these polymers and their bioabsorbable properties. It is hoped that this multidisciplinary approach of surgery and research will continue to help the further evolution of biomaterial science.

The zygomatic bone as a potential donor site for alveolar reconstruction--a quantitative anatomic cadaver study.

The aim of this cadaver study was to evaluate the possibility of using the zygomatic bone as an intraoral bone harvesting donor site and to determine the safety of this harvesting procedure. In addition, the volume of bone material harvested from the zygomatic bone was measured. Twenty fixed adult cadavers were used to yield a total of 40 zygomatic bone harvest sites, from which bone was collected. The volume of bone obtained from the zygomatic harvests was measured with a water displacement method and by compressing the graft into a syringe. The safety of the technique was evaluated by assessing possible encroachment upon the neighbouring structures. After bone harvesting, the zygomatic sites were exposed and evaluated for visible perforations or fractures. Possible damage to the neighbouring tissues was also examined with computed tomography scans at 18 sites in nine cadavers. The average bone graft volume obtained from the zygomatic bone was measured to be 0.53 ml (SD 0.25) with water displacement and 0.59 ml (SD 0.26) with the syringe. The complications in the zygoma included 15 small perforations into the maxillary sinus and 7 perforations into the infratemporal fossa. CT scans showed that bone could be harvested safely without encroaching upon the orbital floor or the surrounding nerves and vessels in the zygoma. The zygomatic bone is a safe intraoral donor site for the reconstruction of small- to medium-sized alveolar defects.

Tuberous sclerosis: clinicopathologic features and review of the literature.

INTRODUCTION: Tuberous sclerosis is a hamartoneoplastic syndrome, which may involve multiple organ systems. Oral hard tissue manifestations of the syndrome have been described in the literature only as recently as 1955. Patients who presented with clinical manifestations of tuberous sclerosis did not routinely undergo oral surveys to rule out 'lesions', and consequently data on 'lesions' in the maxillofacial complex is scant. Ten cases have been found in the English language literature, which describe maxillofacial 'lesions', which may be tumours, new growths, neoplasms or overgrowths occurring in patients diagnosed with tuberous sclerosis. PURPOSE: To review the literature for all maxillofacial lesions associated with tuberous sclerosis and to present an eleventh case of a patient with a maxillofacial lesion diagnosed as having tuberous sclerosis. RESULTS: Eleven cases were found with maxillofacial fibroblastic lesions associated with tuberous sclerosis. These lesions were all fibrous benign neoplasms found in the maxillofacial bony complex. CONCLUSIONS: Maxillofacial fibroblastic lesions in tuberous sclerosis have various histopathological presentations, some of which may be difficult to differentiate. Consequently, close microscopic examination of these lesions is necessary so that adequate surgical treatment is provided.

Impacted third molars and risk of angle fracture.

The purpose of this study was to assess the influence of the presence, position, and severity of impaction of the mandibular third molars, on the incidence of mandibular angle fractures. A retrospective cohort study was designed for patients presenting to the Division of Oral and Maxillofacial Surgery, Toronto General Hospital (Toronto, Canada), for treatment of mandibular fractures from January 1995 to June 2000. The independent variables in this study were the presence, position and severity of impaction of third molars. The outcome variable was the incidence of mandibular angle fractures. Hospital charts and panoramic radiographs were used to determine and classify these variables. The demographic data included age, sex, mechanism of injury and number of mandibular fractures. The study sample comprised 413 mandibular fractures in 214 patients. The incidence of angle fractures was found to be significantly higher in the male population and was most commonly seen in the third decade of life. Assault remained the most significant aetiological factor. Patients with third molars had thrice the increased risk of angle fractures when compared to patients without (P<0.001). Impaction of third molars significantly increased the incidence of angle fractures (P<0.001). The severity and angulation of third molar impactions were not significantly associated with angle fractures. This study provides evidence that patients with retained impacted third molars are significantly more susceptible to angle fracture than those without. The risk for angle fracture, however, does not seem to be influenced by the severity of impaction.