HLA DR4 antigens have been considered as a risk factor in periodontal disease. The aim of this "case control" study was to verify and to provide fuller clarification of such data. "Cases" or patients had to be aged between 20 and 48 years. They presented at least 5 sites spread over several teeth with an attachment loss equal or greater than 6 mm, and 10 sites spread over several teeth with periodontal pockets equal to or greater than 5 mm. Verification with a WHO probe showed an individual CPITN score of 4. Moreover, subjects whose average CPITN score for the 6 sextants was less than 3 were excluded from the study. Among these "severe periodontitis" patients, a subgroup was distinguished composed of subjects aged 20-35 years who presented, in accordance with the cases by Katz and co-workers, 5 or more teeth showing pocket depths of 6 mm or more. The dental chartings of these subjects showed an attachment loss of more than 3 mm on certain teeth over an inter-exam period of 1-3 years. They all displayed obvious loss of bony support in the affected sites. This constituted the "rapidly progressive periodontitis" subgroup. The "controls" were all over 20 years of age, and it was clinically verified that they were free of periodontal disease. There were 48 "cases" and 55 "controls". HLA typing of patients and controls was performed using "sequence oligoprobe hybridization after polymerase chain reaction" in accordance with the 11th International Workshop. This method allowed the detection of DR4 alleles as well as DR4 subtypes. The ethno-geographic origin of the subjects, considered as a confounding variable, was neutralized by stratified analysis. Subtypes 0401, 0404, 0405 and 0408 tended to be more frequent (p=0.08) in the cases (Severe Periodontitis). Focusing on analysis of "rapidly progressive periodontitis" in subjects aged 20-35 years, a very significant Mantel-Haenszel chi2 was obtained (p=0.0058) which led to a Mantel-Haenszel standardized odds ratio (OR) equal to 17. The 95% confidence interval was 1.03<0.R.<180.10. In conclusion, this supports previous reports and gives further clarification: in particular subtypes 0401, 0404, 0405 and 0408 can be considered as a risk factor for "rapidly progressive periodontitis". It should be noted that these determinants have been implicated in rheumatoid arthritis.

One of the main problems for aged people is that of having a balanced diet, improved by correct conditioning of the alimentary bolus. Does the masticatory status influence the appearance of gastrointestinal disorders? Such a question justifies the present study. The present work concerned all the patients (211) of eight geriatric institutions, and was completed by a retrospective approach (case-control study). The main result brought by the case-control study, showed that poor oral functional characteristics represent a risk for gastrointestinal pathology (age being neutralized; odds ratio (OR): 2.62). This result indicates that the loss of teeth must be compensated by functionally effective dentures. Not only will the patients' physical and psychic health improve but also medical and public health problems will be solved.

In oral implantology, successful results in osseointegration are obtained in the medium term (6-12 months) with commercially pure titanium implants. However, current superstructures can be of a different nature (precious metal or titanium) and of different manufacture (cast or machine-produced). Polymetallism between the implant and the superstructure may lead to conditions of galvanic corrosion, and influence osseointegration. The study described establishes, on the one hand, the procedures of animal experimentation in primates and on the other, the techniques of analysis of histological sections. The first technique of analysis is based on histomorphometry and leads to the definition of an osseointegration index. The second technique of analysis consists of X spectrometry by dispersion of energy which enables a spectral analysis of selected points below the crestal neck of the implant (vulnerable area in the case of corrosive attack) to be obtained. It is noted that after 6months, two of which were of activation, osseointegration did not vary according to the nature of the superstructure (precious alloy or titanium). After 2 months, the presence of a precious alloy superstructure lead to titanium migration towards the area around the cervical region of the implant (10-50 microm). This phenomenon did not occur with a titanium implant. It can therefore be presumed that polymetallism leads to detectable corrosion after 2 months but without apparent modification of osseointegration.

The principal purpose of this study was to investigate the speech of two edentulous subjects fitted with a complete maxillary prosthesis made of three different palatal materials: aluminium, resin, stellite. The study was performed using two speakers fitted with a prosthesis (a man and a woman). They took part in the acoustic recording of logatoms read by themselves while wearing various prostheses. These recordings were tested from the auditory point of view by a series of six listeners (four men and two women) in an anechoic room. After 144 different tests, a speech reception threshold (SRT) was defined for each speaker and each different prosthesis. This SRT shows a level of speech intelligibility defined so that the lower the SRT, the more intelligible for the listener. The results show that: (i) both the material and the listener influence SRT: (P < 0.05); (ii) an interaction between the material factor and the speaker factor appears. (P < 0.05); (iii) The hierarchy factors influencing SRT are most important in the order: Listener --> material --> speaker; and (d) The group fitted with a metal prosthesis (aluminium, stellite) was more intelligible regarding the way they were perceived by others.

The present study concerns an investigation carried out to determine the effects of gingival stimulation on the resolution of a human experimental gingivitis. 10 young male dental students participated in the experiment. Following the baseline examination (day 0), the participants were instructed to abstain from all oral hygiene procedures during a 21-day period. Heavy plaque accumulation and gingivitis developed during the 21-day induction period. On the evening of the 21st day, active oral hygiene measures were reinstitued, for an 8-day period, using 2 different methods. For the left side of the maxillary arch, a hygiene procedure including gingival stimulation was prescribed. On the other hand, for the right side, a hygiene method without gingival stimulation was instituted. On both sides of the upper arch, the gingival condition was assessed by means of the gingival index, and soft deposits were assessed by the plaque index (selected teeth: 13, 14, 15, 23, 24, 25). Measurements were performed on days 0, 21, 22, 23, 24, 25, 26, 27, 28, 29. On day 29, ideal oral hygiene conditions and gingival health were re-established on both sides. However, a statistical analysis of the data collected during the recovery period revealed that gingival index scores were temporarily, but significantly, higher on the side where mechanical stimulation was performed, although plaque deposits there decreased more rapidly. Thus the present work supports the idea that gingival stimulation does not in any way improve recovery from experimental gingivitis.

The role played by gingival stimulation has not yet been clearly explained. This experiment shows (1) that even with regular stimulation of the gingiva with a toothbrush, gingival inflammation indices (GI and SBI) increase when plaque (determined by PII) accumulates on tooth surfaces; and (2) that if one proceeds to routine plaque elimination from the tooth surfaces, gingival inflammation indices (GI and SBI) increase in the absence of regular mechanical stimulation of the gingiva with a toothbrush. In the latter case, inflammation may be related to plaque accumulation on the gingiva.