Efeito da ciclofosfamida sobre o desenvolvimento de germe dental do incisivo do camundongo.

Thirty six female mice were injected on the 12th day of the gestational period with 0.2 ml of distilled water (control group) or of an acqueous solution containing either 30 mg/Kg or 50 mg/Kg of body weight of cyclophosphamide (treated group). The animal were killed at 24, 48, 72, 96 and 120 hours after the injection and 3 days after birth. It was verified that cyclophosphamide interferes on the tooth germ development and that this effect is in directly ratio of the doses used.

Estudo da penetração de agentes ácidos para o condicionamento do esmalte dental em cimentos à base de hidróxido de cálcio.

It was verified the penetration of phosphoric acid into 3 commercial calcium hydroxide-based cements (Life, Renew and Prisma VLC Dycal). The colorimetric method employed permitted the identidication of phosphorus amount in representative samples of 6 successive layers 0.1 mm thick of each material. The acid etching used were the commercial products Scotchbond Etching Gel--3M at 36.114% by weight and Solução Condicionadora--Johnson & Johnson at 36.054% by weight. The contact time was 60 seconds. The result showed that layers 0.1 mm tick for Life and Prisma VLC Dycal and 0.2 mm thick for Renew were able to block the penetration of phosphoric acid solution whereas layers 0.1 mm thick for the 3 cements were able to block the penetration of phosphoric acid gel.

Efeitos da estimulação ultra-sônica sobre o processo de reparo em ferida de extração dental: estudo histológico em ratos.

The effects of ultrasound on the wound healing process after teeth extractions were studied histologically. The right upper incisor was extracted in 56 rats. They were divided into 2 groups, one control (I) and one experimental (II). Group II received ultrasound stimulation that was applied with the frequency of repetition of 1,000 Hz and pulse length of 2,000 us continuously, during five minutes daily since the extraction day until 24 hours before the death. The rats were sacrificed at 3, 6, 9, 12, 15, 18, and 21 postoperative days. The results showed a precocious granulation tissue formation, faster remodeling of osseous ridges, and consequently acceleration of the alveolar wound healing process.

Metallurgical evaluation of a copper-based alloy for dental castings.

The present study was designed to evaluate the metallurgical properties of an experimental, low-cost copper-zinc-aluminum-nickel alloy for dental castings. Some specimens were subjected to heat treatment after induction casting. The extent of corrosion was determined by measuring weight loss of specimens stored in a sodium sulfite solution. In the as-cast specimens, tests demonstrated the presence of three phases: the first consisted of copper-zinc-aluminum, the second was similar but lower in copper and aluminum, and the third consisted of an intermetallic compound of manganese-nickel-phosphorus. After heat treatment, the first phase remained relatively constant, the second was converted to Cu3Al, and the third increased in volume. The weight loss from the as-cast specimens was eight times that of the heat-treated specimens. It was concluded that the heat treatment substantially changed the microstructure and improved the corrosion resistance of the experimental alloy.

CPITN: time and cost estimates for periodontal prevention and treatment procedures.

The aim of this study was to estimate the necessary time and cost for periodontal prevention and treatment in a working population from sugar and alcohol refineries in Araraquara, SP, Brazil. A stratified sample of 528 employees aged 18-64 from administrative, industrial and agricultural staffs was examined by one examiner, previously trained, according to the community periodontal index of treatment needs (CPITN). The time required for procedures and the cost was extrapolated to the total worker population. The results showed that the estimated time required for periodontal prevention/treatment was 4527 hours. Of this time, 1783 hours were required for oral hygiene instruction, 2531 for scaling, 151 for surgery and 62 for maintenance. The cost would be US $17,655 for hiring a dentist for 8 hours/day to provide oral hygiene instruction, scaling, surgery and maintenance. However, the cost would be US $9,028 for hiring a dentist for 4 hours/day to provide surgery and maintenance and a dental hygienist for 8 hours/day to provide scaling and oral hygiene instruction. Taking into account epidemiologic, technical and economic aspects, the decision relating to manpower should be this second option.

A study of different calcification areas in newly formed bone 8 weeks after insertion of dental implants in rabbit tibias

In orofacial implantology there are many types of implants for the different systems. Among these is the implant surface type, e.g., a screw type, cylindrical and laminar. Furthermore, the implants are different in their dimensions, their metal composition, their surface condition, such as smooth, grit or layered surfaces and in their methods of application. Two different self-tapping implants, one smooth and the other grit-blasted, are screwed into the bone, and another one with a plasma of titanium coating, which is also in a screw form but with greater spaces between the screw threads are compared. The greatest amount of bone deposition in the bone/implant interface was encountered in the latter one, the smooth surfaced implant being in second place. All of these systems can alter the implant healing process and to demonstrate this, we injected bone markers in the rabbits over different periods of time so as to observe the different areas of bone deposition in the tibias where the implants had been inserted. The bone tracers used were Alizarin, Calcein and Xylenol-orange. The amount of deposition was calculated by using the method of surface morphometry.

Loss of space and dental arch length after the loss of the lower first primary molar: A longitudinal study

The premature loss of primary teeth may harm the normal occlusal development, although there are debates relating to the necessity of using space maintainer appliances. The aim of the study is to evaluate the changes in the dental arch perimeter and the space reduction after the premature loss of the lower first primary molar in the mixed dentition stage. The sample consists of 4 lower arch plaster models of 31 patients, within the period of pre-extraction, 6, 12 and 18 months after the lower first primary molar extraction. A reduction of space was noted with the cuspid dislocation and the permanent incisors moving toward the space of the extraction site. It was concluded that the lower first molar primary premature loss, during the mixed dentition, implicates an immediate placement of a space maintainer.