Bond strength of disinfected metal and ceramic brackets: an in vitro study.

The aim of this in vitro investigation was to test whether disinfecting with Chlorhexamed fluid had an influence on the shear bond strength of metal and ceramic orthodontic brackets. Metal and ceramic brackets were fixed by the composite adhesives Transbond XT (light curing) and Concise (chemical curing) to 224 bovine permanent mandibular incisors. Bovine teeth were divided into eight groups of 28 each as group 1: metal bracket/Transbond XT, group 2: disinfected metal bracket/Transbond XT, group 3: metal bracket/Concise, group 4: disinfected metal bracket/Concise, group 5: ceramic bracket/Transbond XT, group 6: disinfected ceramic bracket/Transbond XT, group 7: ceramic bracket/Concise, and group 8: disinfected ceramic bracket/Concise.

Investigations on the influencing of the subgingival microflora in chronic periodontitis. A study in adult patients during fixed appliance therapy.

Aim: The aim of the present study was to investigate changes in the subgingival flora in adults with chronic periodontitis undergoing orthodontic fixed appliance therapy.

Patients And Methods: In seven adult patients who had undergone nonantibiotic periodontal pretreatment, the subgingival bacteria were subjected to microbiological examination and the number of periodontopathogenic organisms was determined before (T1: prior to treatment being started), during (T2: 6 weeks after orthodontic treatment was started) and after the end of orthodontic treatment (T3: 6 weeks after removal of the fixed appliances).

Results And Conclusion: During the fixed appliance therapy (metal brackets, NiTi archwires, stainless steel archwires), a marked reduction was observed in the total bacteria count from the subgingival pocket despite the clinical periodontal parameters remaining almost unchanged.

Abnormal pulp calcification in primary molars after fluoride supplementation.

Forty-five caries-free primary molars from children with continuous fluoride supplementation (n = 28) after birth and from children without fluoride prophylaxis (n = 17) were investigated by light microscopy. The following results were obtained: The prophylaxis group evidenced a special form of calcification consisting of fibrodentin-like hard tissue developing intramurally in the dentin wall especially at the pulp floor and spreading irregularily into the pulp cavity by displacing the degenerating pulp tissue (n = 24). These teeth were ankylosed in the bi- and trifurcation area as well as inside the roots.

Apoptotic epithelial cell death: a prerequisite for palatal fusion. An in vivo study in rabbits.

Unlabelled: The aim of the present study was to investigate stage-specific changes in medial edge epithelium during in vivo fusion of embryonic palatal shelves in 25 Russian rabbits.

Material And Methods: The embryos were dissected following Caesarian section at day 18. Palatal shelves of specific developmental steps (approximation, contact, fusion) were examined by light microscopy, immunohistochemistry and transmission electron microscopy.