Annals of the Royal Australasian College of Dental Surgeons最新文献

The starting point for defining a therapy, whether in dentistry or the various areas of medicine, is to understand the aetiology and progression of the different illnesses. In this context, it is worth pointing out that periodontal diseases are a group of infections whose primary aetiological factor is the bacteria present in the oral cavity, especially those that colonize the supra- and subgingival tooth surfaces. Many advances, mainly those occurring over the last two decades, greatly facilitated understanding of the aetiopathogenesis of periodontitis, including the microbiota related to each type of disease and the host response. This knowledge has made it easier to indicate more specific therapy, including the use of systemic antibiotics. Systemically administered metronidazole, and especially the combination of metronidazole, amoxicillin and scaling and root planing (SRP) leads to a beneficial change in the composition of the subgingival microbiota by reducing pathogens and allowing the growth of host-compatible species. In addition, the combination of systemic antibiotics and a strict control of supragingival plaque during the active phase of therapy has been showing promising results in the treatment of chronic periodontitis.

The aim of the study was to compare the surgical complications and neurosensory disturbance of coronectomy and conventional excision of lower third molars with roots in close proximity to inferior dental nerve. We conducted a randomized clinical trial of patients with lower third molars showing specific radiographic signs was conducted. Patients were randomized to undergo either coronectomy or total excision (control) of the lower third molar. It was concluded that coronectomy can significantly reduce the incidence of inferior dental nerve deficit when compared with conventional excision when the roots show radiographic signs of close proximity, and the technique showed a similar rate of other surgical morbidities.

Nicotine is the main chemical component in tobacco products and its effect on bone healing remains controversial. This study aims to evaluate the influence of nicotine on blood perfusion and bone healing using a rabbit model of mandibular distraction osteogenesis. The dose dependent effect of nicotine on bone regeneration, and the effect of nicotine on blood perfusion and angiogenesis were assessed by radiography, micro-computed tomography, histological and immunohistochemical analysis, real time PCR and Laser Doppler monitoring. Results showed that bone healing was compromised by high dose nicotine treatment. Nicotine exposure increased microvessel density, whereas inhibited blood flow and bone formation. The expression of bone morphogenetic protein (BMP)-2 in osteoblasts was also decreased. The present study supported that nicotine has a dose dependant influence on bone healing in distraction osteogenesis. Nicotine compromises bone regeneration possibly by causing ischemia and inhibiting BMP expression in osteoblasts. Nicotine exposure enhances angiogenesis but can not compensate for the adverse effect of vasoconstriction.

Unlabelled: There has been a paradigm shift within orthodontics in the use of lingual fixed appliances compared with the use of labial fixed appliances on the basis of perceived benefits and acceptance by patients.

Methods: A matched case-control prospective longitudinal study of adult patients treated in the Orthodontic Department, Prince Philip Dental Hospital, Hong Kong. Group A consisted of 30 patients treated with lingual orthodontic appliances. Group B consisted of 30 patients treated with labial orthodontic appliances. Data were collected at five different time points using questionnaire: pre-treatment; one week after the placement of the fixed appliance, and then at 1-month, 3-months, and 6-months thereafter. The questionnaire consisted of 15 items, in which 11 items were rated on a visual analogue scale.

Results: Patients' experience of pain decreased over the study period (p < 0.001); Those treated with lingual appliances reported significantly greater pain experience than those treated with labial appliances with respect to tongue pain (p < 0.001). However, those treated with labial appliances reported experiencing significantly more lip pain (p < 0.01), cheek pain (p < 0.001), and gum pain (p < 0.05). Patients treated with lingual appliances reported experiencing pain earlier on than those treated with labial appliances (p < 0.05). Both groups reported the pain level to be the same throughout the day (p > 0.05). There was no significant difference in reported disturbance of sleep or analgesic consumption between the two groups (p > 0.05).

Conclusion: Patients treated with both labial and lingual orthodontic appliances experienced pain during treatment, but this decreased over the treatment period. Patients treated with lingual appliances experienced more tongue pain whereas those treated with labial appliances experienced more lip, cheek and gum pain. Patients treated with lingual appliance reported experiencing pain earlier on than those treated with labial appliances.

Distraction osteogenesis or callostasis is a technique of new bone formation by gradual separation of bony fragments. The method was first developed for limb lengthening but recently this process was widely applied to the cranio-maxillofacial bones. The application included unlimited bone lengthening and reconstruction of segmental defects. Several designs of extra-oral and intra-oral distraction devices were invented to suit different areas of craniofacial bone. Nevertheless intraoral distractors have several advantages including minimal scarring and being less cumbersome. Clinical cases using distraction osteogenesis as an alternative treatment to conventional surgical procedures for maxillo-mandibular lengthening and reconstruction of alveolar segmental defects after tumour resection before implant installation are presented and discussed.

Background: Spark discharge anodic oxidation forms a porous TiO2 film on the surface of titanium oral implants, increasing surface roughness and concentrations of calcium and phosphate ions. In this study, anodic-treated oral implants were placed in an animal model and analysed using clinical, micro-computerized tomographic (micro-CT) and histometric techniques.

Methods: Pairs of 3.5 mm x 8.5 mm long titanium implants (Osstem Implant Co., Ltd. Seoul, Korea), with blasted (control) or blasted and oxidized surfaces (test), were placed into the right femoral condyles of 10 sheep. Animals were sacrificed after 1 month unloaded healing. Resonant frequency analysis (RFA) was measured in implant stability quotient (ISQ) using the Mentor II device. Specimens were scanned using medium resolution micro-CT (Skyscan 1172). Mean percent bone-to-implant contact (%BIC) was calculated from two images per implant by three different operators, using Image J software. Inter- and intra-examiner differences were calculated. Specimens were then embedded in methacrylate and undemineralized ground sections were digitized. Mean %BIC was measured using Image J at x 20 magnification for the best-three consecutive threads from the most central section.

Results: Mean micro-CT %BIC was similar for control and test (57.2 +/- 0.05% versus 56.4 +/- 0.03%, p = 0.5). There was considerable inter-examiner variability (interclass correlation coefficient = 0.44). RFA showed no clinically-detectable difference between the two groups (control ISQ: 75.2 +/- 4.2; test ISQ: 76.3 +/- 1.7; p = 0.48). However, histometric analysis found a marked and highly statistically-significant difference (%BIC Test 72.5 +/- 8.6%, Control 46.2 +/- 12.1%, p = 0.01).

Conclusions: The novel anodic oxidation technique increased early ossointegration of rough-surfaced implants by 157%. Neither clinical testing with resonant frequency analysis nor radiographic analysis using micro-CT had sufficient resolution to detect this improvement. Whether this gain in early bone-implant contact is clinically significant in the context of early occlusal loading is the subject of subsequent experiments.