Histomorphometric analysis of rat alveolar wound healing with hydroxyapatite alone or associated to BMPs

Several materials and techniques have been proposed to improve alveolar wound healing and decrease loss of bone height and thickness that normally follow dental extraction. The objective of this research was the histologic analysis of bone morphogenetic proteins implanted into dental alveoli of rats after extraction. A total of 45 adult male Wistar rats were divided into three groups of 15 animals each: control (no treatment), implanted with pure hydroxyapatite (HA, 3 mg) and implanted with hydroxyapatite plus bone morphogenetic proteins (HA/BMPs, 3 mg). Five animals from each group were sacrificed at 7, 21 and 42 days after extraction for the histometric analyses of the osteoconductive potential of hydroxyapatite associated or not with BMPs. After dissection, fixation, decalcification and serial microtomy of 6-micron thick sections, the samples were stained with hematoxylin-eosin for histologic and histometric analyses. Both HA and HA/BMPs caused a delay in wound healing compared to control animals, evaluated by the percentage of bone tissue in the alveoli. The treatment with HA/BMPs had the greatest delay at 21 days, even though it produced values similar to the control group at 42 days. The materials did not improve alveolar repair in the normal period of wound healing and the association of HA/BMPs did not have osteoconductive properties with granulated hydroxyapatite as the vehicle.     

Acute onset of facial nerve palsy associated with Lyme disease in a 6 year-old child

Pediatric facial nerve palsy (FNP) can result from a variety of etiologies including Lyme disease, varicella, primary gingivostomatitis, herpes zoster oticus (Ramsay Hunt syndrome), coxsackievirus, trauma, otitis media, HIV, diseases causing tumors or demyelinations, compressions, and possibly Epstein Barr virus. Lyme disease has been implicated as the cause of over 50% of the FNPs in children. The paralysis of the facial nerve disturbs motor function to the muscles of facial expression and results in a flaccid appearance of the face (unilateral or bilateral). This case report derails undiagnosed Lyme disease presenting as a facial palsy in a 6 year, 5 month-old white female. The palsy was recognized and consultation with the child's physician prompted definitive diagnosis and treatment. A review of the literature and the implications of facial nerve palsy are discussed.     

The osteoinductive potential of demineralized freeze-dried bone allograft in human non-orthotopic sites: a pilot study

BACKGROUND: The use of demineralized freeze-dried bone allograft (DFDBA) in periodontal therapy is widely accepted. In addition to histologic studies demonstrating its role in regenerating the attachment apparatus, its recognized ability to exhibit osteoinduction in small laboratory mammals has prompted many clinicians to regard it as osteoinductive when utilized in periodontal therapy. Despite such a theoretical deduction, evaluating and establishing the osteoinductive potential of DFDBA in humans has been problematic. The purpose of this study was to investigate, through the use of a novel implantation/recovery model, the potential of DFDBA to induce new bone formation at sites not normally considered capable of de novo osteogenic activity. METHODS: Seven patients scheduled to undergo periodontal therapy utilizing non-absorbable membranes agreed to have sterile polypropylene mesh capsules placed adjacent to the primary surgical site for the purpose of this investigation. One capsule was left empty while the second capsule contained DFDBA. At the appropriate time interval for removal of the therapeutic membrane, the capsules were removed and submitted for histologic analysis. Five of the subjects had procedures directed at regenerating bone within molar furcations (guided tissue regeneration) and had the membranes and associated capsules removed between 6 and 8 weeks. The 2 remaining patients had procedures directed toward ridge augmentation (guided bone regeneration) and had the membranes removed either at 8 or 9 months, respectively. In addition, one of the 2 long-term membrane patients had liberal cortical penetration performed directly beneath the implanted capsule. RESULTS: Histologic analysis of all recovered capsules by 2 independent oral and maxillofacial pathologists could not confirm the presence of either osteoblastic or osteoclastic activity associated with the DFDBA particles, although the 2 longer-term specimens clearly exhibited trace amounts of vital bone non-contiguous with the implanted material. CONCLUSIONS: The results of this pilot study do not support the osteoinductive potential of DFDBA when utilized in quantities normally associated with periodontal bone grafting, although they do support the use of this implantation/recovery model to study other preparations and mechanisms of bone formation.     

Delayed iliac abscess as an unusual complication of an iliac bone graft in an orthognathic case

The reconstruction of large maxillofacial defects generally requires harvesting bone from extra-oral sites. The main source of autogenous bone is the iliac crest. This donor site is used to obtain bone for augmentation in orthopaedic surgery, neurosurgery, and oral and maxillofacial surgery, where the main indications are secondary and tertiary osteoplasty in patients with cleft-lip and palate, reconstruction of bony defects after operations for tumours, and augmentation of severe atrophy of the alveolar crest in preprosthetic surgery. A review of the literature on complications following bone harvesting from the anterior iliac crest reveals persistent pain, nerve injury, haemorrhage, limping, persistent gait abnormalities, conspicuous scarring, bone contour alteration, infection, fracture, meralgia paraesthetica, peritonitis, and herniation. The authors report an unusual complication: a huge iliac abscess that appeared 4 years after bimaxillary surgery involving iliac bone grafts.     

Clinical crown length of the maxillary anterior teeth preorthodontics and postorthodontics

BACKGROUND: Prevalence information on excessive gingival display in postorthodontic patients is limited. By studying the size relationship of the clinical crowns of teeth, in an orthodontic population, we can begin to quantify their need for periodontal plastic surgery. METHODS: Preorthodontic and postorthodontic crown dimensions were measured on 200 plaster models, and after 5 years, 31 of the subjects were recalled to repeat the measurements in a clinical examination. The measurements included clinical crown lengths and widths of the six anterior teeth, and these values were compared to known ideals. RESULTS: This study revealed a significant increase in the length of the maxillary anterior crowns over the three examinations, yet these values were still approximately 1.5 mm shorter than ideal. The mean crown width-to-length ratio was 87% to 88% for maxillary central incisors, clearly above the accepted "ideal." In addition, 61% to 71% of maxillary central incisors exceeded allowable crown width-to-length ratios, and 61% of subjects displayed asymmetry in gingival architecture. CONCLUSIONS: Although this study only examined one aspect of excessive gingival display, to our knowledge it is the first study to show that in a predominantly young, postorthodontic population, the prevalence of non-ideal width-to-length ratios is >65% and the presence of asymmetry is >60%. Therefore, close interaction between the periodontist and the orthodontist is necessary to diagnose these conditions to provide patients with all options for improving their smile.     

Long-term evaluation of bilateral cleft lip and palate patients after early secondary closure and premaxilla repositioning

The aim of this retrospective, mixed longitudinal study was to assess the long-term outcome of early secondary closure and premaxilla osteotomy in 40 bilateral cleft lip and palate patients who underwent early secondary osteotomy of the premaxilla and bone grafting at the age of 8-12 years. Clinical and cephalometric evaluations of profile, lip relation, nasolabial angle and position of the maxilla preoperatively, postoperatively and at adolescence were compared to normal values of non-cleft individuals and the reported data of 90 bilateral cleft lip and palate patients treated in Oslo. In 68% of patients the profile was considered acceptable, but in 26 maxillary growth appeared to be impaired by cephalometric standards. In four patients a Le Fort I osteotomy was carried out and nine patients would have benefited from such a procedure. This study reveals a trend towards maxillary growth retardation partially compensated by orthodontic and dental treatment. Since the results are comparable to those reported for the Oslo group with regard to maxillary growth, the surgical protocol followed does not require revision. Considering the benefits, i.e. closure of alveolo-palatal cleft, continuity of dental arch, eruption of canine in the graft and closure of oro-nasal communications, this mode of treatment should be continued.     

Thermal analysis of commercial Gutta-percha using differential scanning calorimeter and dynamic mechanical thermal analysis.

Gutta-percha is the most widespread root canal filling material and knowledge of its chemical and thermomechanical properties is of a great interest to its use in clinical dentistry. In the present investigation, the results from differential scanning calorimeter were compared with those obtained by dynamic mechanical thermal analysis. A significant correlation was established between these results and the chemical composition of six different commercial samples of gutta-percha.