The effects of antibiotic-supplemented bone allografts on contaminated,partially avulsive fractures of the canine ulna

The use of antibiotic-supplemented bone allograft as a material for placement in contaminated fractures of the dog ulna was investigated. Demineralized, freeze-dried bone allografts mixed with antibiotics and gelatin were placed in five fractures contaminated with Staphylococcus aureus (Washington Hospital strain) and Pseudomonas aeruginosa (PA 220). The results of treatment with antibiotic-supplemented bone allografts were compared with the results of conventional treatment in five additional experimental animals in which fractures contaminated with S. aureus and P. aeruginosa were created. The five fractures treated by conventional methods developed acute osteomyelitis and nonunion, whereas the ASBA-treated fractures resulted in bone union without infection. ASBA-treated fractures were stable and had 89% of the shearing strength of the non-fractured, contralateral ulnae five months after treatment.     

Osteogenic activity of antibiotic-supplemented bone allografts in the guinea pig

This study evaluated the osteogenic potential of bone allografts supplemented with up to 1000 times the minimum inhibitory concentration of cephalothin and tobramycin effective against Staphylococcus aureus and Pseudomonas aureus. Mineralized and demineralized bone allografts with and without antibiotics were compared in calvarial defects of guinea pigs. Strontium-85 uptake and histologic evaluation indicated there was no significant difference in osteogeneic activity between nonantibiotic-supplemented allografts and antibiotic-supplemented allografts.     

Experimental mandibular osteomyelitis: Therapeutic trials with hyperbaric oxygen

Hyperbaric oxygen (HBO) has been reported to be beneficial in the treatment of mandibular osteomyelitis; however, controlled laboratory studies have been limited to the long bones. In this study, osteomyelitis was created in surgically fractured rabbit mandibles by inoculation of Bacteroides melaninogenicus. Two months after inoculation, osteomyelitis was verified by bacterial cultures and inspection of the fracture sites. The animals were then randomly divided into treatment and control groups. The treatment group received HBO (2 atmospheres) for two hours daily for 40 treatment days, whereas the control group was maintained on ambient air. Although HBO therapy did not eliminate the chronic osteomyelitis, it did result in a significant improvement in sinus tract healing, osseous repair, and diminished mobility at the fracture site.     

Psychological considerations in maxillofacial prosthetics

An attempt has been made to integrate information from psychological principles and clinical research which is relevant to maxillofacial prosthetics. Attention was given to the role of body parts in the human experience, with particular consideration of facial aspects. The importance of the maxillofacial region in early development, personality dynamics, and day-to-day interpersonal relationships was reviewed together with several specific problems which often accompany maxillofacial changes in structure or function.The dentist must be concerned with the patient's expectations, personality characteristics, and ability to accept and integrate the prosthesis. Several implications for clinical practice were presented. The dentist's understanding and utilization of psychological considerations should result in increased effectiveness in treatment and rehabilitation of maxillofacial patients.     

A comparison of freeze-dried allogeneic and fresh autologous vascularized rib grafts in dog radial discontinuity defects

The limitations of autologous vascularized grafts include morbidity at the donor site and the increased surgical time associated with graft retrieval. To overcome these limitations, freeze-dried allogeneic and fresh autologous vascularized rib grafts were compared in 6-cm mid-radial defects of dogs. There was no statistically significant difference between the two graft systems when postoperative radiographs, in vivo intraarterial angiograms, and histologic evaluation of vessel patency were compared. However, clinical assessment of graft stability favored the autologous grafts, and force deflection tests revealed that the freeze-dried grafts had only 64% of the graft strength of the fresh autologous grafts at the end of the experiment at 26 weeks.     

The effect of chronic red cell mass depletion on the healing of bone grafts

The purpose of this study was to determine whether a marked decrease in red cell mass with a normal blood volume (normovolemic anemia) would compromise osseous repair in experimental mandibular bone grafts. In adult male dogs, osseous defects in the mandibular body were restored with combined allogeneic and autologous bone grafts. In the experimental group, the red cell mass was depleted by a mean 55% of the baseline value and the resulting anemia maintained for eight weeks by serial phlebotomies. In the control group phlebotomy was not performed. Osseous repair was evaluated by quantitative sequential radionuclide imaging, subjective and quantitative determinations of graft stability, and histologic examination. Results demonstrated no significant difference in bone graft repairs between the anemic and control animals by any of the evaluation methods over the eight-week period of study (P greater than 0.05).     

Factors associated with faculty participation in research activities in dental schools

BackgroundTo quantify participation in dental research activities in Malaysia, and investigate its association with socio-demographic and professional characteristics, and perceptions of research and development (R&D) culture.Materials and methodsDental academics in Malaysian dental schools were invited to complete a questionnaire by email and post. The survey comprised questions on research activities in the past 12 months, socio-demographic and professional characteristics, and the R&D Culture Index. Principal components factor analysis was carried out to confirm the factor structure of the R&D Culture Index. Chi-square test was used to identify association of research activities with R&D culture, and socio-demographic and professional characteristics. Binary logistic regression was carried to identify predicators of research activities.ResultsOf 256 potential participants contacted, 128 (50%) useable responses were returned. Three R&D Culture factors accounting for 57.4% of variance were extracted. More positive perception of R&D Support was associated with Malaysians (0.025) and those employed in Government schools (0.017). R&D Skills and Aptitude were associated with older respondents (0.050), PhD qualification (0.014) and more years in academia (0.014). R&D Intention was associated with any of the socio-demographic characteristics. Thirty (23.4%) respondents reported a peer-review research publication in the past 12 months, which was associated with having a PhD (OR 12.79, CI 1.28–127.96), after adjustment in regression analyses.DiscussionPostgraduate research training should be encouraged to promote participation in research activities. R&D culture did not appear to impact on research productivity. Other factors such as individual attitudinal interests should be studied.     

Effect of ultrasonic instrumentation on the retention of simulated cast crowns

The effect of ultrasonic instrumentation on the retention of cemented cast restorations was studied. Forces required to dislodge castings from specimen assemblies subjected to ultrasonic vibrations did not differ significantly from those required to cause failure of noninstrumented specimens. The results indicate that clinical application of the ultrasonic device would not affect adversely the retention of properly cemented and well fitting cast restorations.     

Antibiotic practices in non-condylar mandibular fractures: a Maxillofacial Trainee Research Collaborative (MTReC) UK-wide survey

Non-condylar mandibular fractures are consdered ‘open’ fractures and as such are thought to require prophylactic antibiotics. There is no overall consensus on the optimal regimen or choice of antibiotic in the preoperative and postoperative periods due to a lack of high-quality evidence. We therefore set out to ascertain the current UK-wide practice of antibiotic prescribing for non-condylar mandibular fractures. We used a web-based online survey (Google Forms) that was disseminated via email and social media platforms to oral and maxillofacial surgery (OMFS) consultants and trainees of all grades. The questions focused on usual antibiotic practices and typical clinical management of non-condylar mandibular fractures. We gathered information on preoperative antibiotics, and on perioperative and postoperative periods. We collected data from 50 different UK OMFS units representing a broad snapshot of national practice. The majority of responders were speciality trainees (36%) followed by dental core trainees (34%). A total of 45/50 centres routinely admitted patients, and preoperative intravenous antibiotics were commenced on admission by 77/89 respondents, intravenous being the chosen route in all cases. In the preoperative period 81% prescribe co-amoxiclav. In 91% of cases, open reduction and internal fixation (ORIF) was on general emergency (CEPOD) operating lists, whilst dedicated OMFS trauma lists accounted for 9%. With respect to timing, 49% aimed to carry out ORIF within 24 hours from the time of admission, 44% aimed for surgery within 24 - 48 hours, and 6% aimed for surgery on a semielective basis (48 hours or more). Postoperative antibiotics were prescribed routinely by 88% of responders. Preoperative intravenous prophylactic antibiotics are commonplace in non-condylar mandibular fractures. This UK-wide survey demonstrated significant variability in antibiotic prescribing practices, especially in the postoperative period. Most units still rely on CEPOD emergency theatres to provide the capacity for ORIF in this patient group.     

Pathosis of the hard and soft palate.

In this article a few of the more recently emphasized and pertinent conditions that may affect the hard and soft palate have been discussed. The purpose of the article is not to present in all-inclusive classification of lesions occurring the palate. Disease of the palate may be local in nature or may reflect a systemic condition. Dentists must be conscious of the palate as the site of many possible pathoses. The prosthodontist in particular must observe and carefully evaluate the palate and insure its good health before he can prescribe a prosthesis to cover it. Dentistry provides a health service which affects the entire human organism and not just the oral cavity. Therefore an understanding of the varied nature of pathosis as it relates to the oral cavity, and especially the palate, is essential. Continuous surveillance of the palatal regions insures that the dentist's obligation to detect oral abnormalities in patients is in large measure fulfilled.     

Effect of methylprednisolone on swelling after orthognathic surgery

The effectiveness of methylprednisolone for the reduction of postoperative facial edema was evaluated by the computed tomographic examination of 39 patients who underwent either a Lefort I osteotomy or a transoral vertical osteotomy. Results of the CT scans, which were performed preoperatively and at 24 and 72 hours postoperatively, showed that in the LeFort I osteotomy patients methylprednisolone reduced the degree of facial edema by 61% at 24 hours postoperatively and by 10% at 72 hours. In the transoral vertical osteotomy patients methylprednisolone reduced the degree of facial edema by 38% at 24 hours postoperatively and by 45% at 72 hours. It was concluded that methylprednisolone is effective for the control and management of postoperative facial edema following orthognathic surgery.     

Use of hydroxylapatite for the augmentation of deficient alveolar ridges

Investigations were undertaken to evaluate nonresorbable, particulate ceramic hydroxylapatite (durapatite) for augmentation of deficient alveolar ridges. One hundred and fifteen augmentations in both jaws were reported for 110 patients over a 33-month postoperative period. Subjective and objective data show that the implant was successful for all classes of ridges augmented; height, bulk, contour, and ridge form generally improved, and soft tissue overlying the augmented ridges was firm and immobile. Impressions for dentures were usually obtained four to six weeks after surgery, and the dentures were more stable, retentive, and esthetically pleasing than the preoperative prostheses and required fewer relinings. Other than transiently altered sensations resulting from mental nerve manipulation during surgery, patients had few complications. No infection or bone resorption beneath the implant was observed throughout these studies. It was concluded that hydroxylapatite particles placed through a subperiosteal tunnel offer a highly successful method of ridge augmentation and eliminate the most serious problems associated with the use of autogenous or banked bone, namely, morbidity, risk, costliness, and poor results.     

Comparison of fresh autogenous and freeze-dried allogenic skin for mandibular vestibuloplasty

This study compared the ability of fresh autogenous and freeze-dried allogenic split-thickness skin grafts to maintain vestibular depth following vestibuloplasty. Both graft systems resulted in covering of the alveolar ridge by firmly attached tissue, which would be expected to enhance prosthetic stability. The appearance of the fresh autogenous grafts was consistent with that of mature skin grafts, whereas the freeze-dried grafts had the appearance of alveolar mucosa. Vestibular depth stabilized at six weeks with both graft systems, and at six months there was no significant difference (P less than 0.05) between the freeze-dried and fresh grafts with respect to their ability to maintain vestibular depth.     

Intradermal skin wound closure in guinea pigs

The study compares the use of polyglycolic acid suture and nylon suture for closure of skin incisions of the oral and maxillofacial region. Clinical appearances, wound breaking strengths, and inflammatory responses were compared. Using these criteria, polyglycolic acid appears to be superior to nylon.