Porphyromonas gingivalis in an edentulous proband. A case-report

The effect of a commercial probiotic drink on oral microbiota in healthy complete denture wearers

Background

It is acknowledged that oral and general health status declines with age. The global population of denture wearers is increasing, so is the incidence of denture biofilm-related problems, such as denture-associated stomatitis, aspiration pneumonia and malodour. It has been suggested that consumption of probiotic bacteria may improve oral health. However, the effects of probiotics on the oral microbiota of denture wearers have received little attention.

Methods

The aim of this study was to investigate the effect of consumption of a commercial probiotic product (Yakult) on microbiota of saliva, tongue and denture biofilm in healthy complete denture wearers. Eight healthy complete denture-wearing National Health Service (NHS) patients undertook a 7-week trial comprising three phases: baseline; 4-week consumption of one bottle of Yakult per day, each containing a minimum 6.5×10⁹ viable cells of Lactobacillus casei strain Shirota (LcS); 4-week washout period. The microbial viability and composition of saliva, tongue dorsum coating and denture biofilm were assessed using a range of solid selective and indicator media. Questionnaires were used to explore participants’ denture cleaning habits and impact of wearing dentures on their life quality and well-being [modified oral health impact profile (OHIP-14)] prior to and after the study.

Results

Seven volunteers (1 male, 6 females) completed the trial. LcS temporarily colonised oral cavity and denture surface. There was no significant change in the viability of Streptococcus mutans, acidogenic microorganisms, total anaerobic species and Gram-negative obligate anaerobes between study phases. There was no obvious effect of LcS on occurrence and viability of Candida. Participants presented a good general knowledge of denture hygiene and their responses to OHIP-14 questionnaires improved after completing the study (p=0.16).

Conclusion

It appeared that 4-week consumption of probiotic drink had no overall effect on selected oral parameters in healthy denture wearers despite temporary presence of LcS.

Feasibility and Influence of the Microgap of Two Implants Placed in a Non-Submerged Procedure: A Five-Year Follow-Up Clinical Trial

BACKGROUND

The aim of this study was to evaluate the feasibility of using a two-piece implant system in a non-submerged procedure and to study the impact of the microgap between the implant and abutment.

METHODS

Sixty edentulous patients (Cawood Class V-VI) participated in this study. After randomization, 20 patients received two two-piece implants placed in a non-submerged procedure, 20 patients received two two-piece implants placed in the traditional submerged procedure, and 20 patients were treated with two one-piece dental implants placed in the traditional non-submerged procedure. The implants were placed in the mandible for overdenture treatment. A standardized clinical evaluation was performed and radiographs were taken immediately after denture insertion and yearly up to 5 years. Peri-implant samples were collected 12, 36, and 60 months after loading with sterile paper points and analyzed for the presence of putative periodontal pathogens using culture techniques.

RESULTS

One two-piece implant of the non-submerged group and one two-piece implant of the submerged group were lost after 6 and 12 months, respectively. After 5 years of functioning, no significant clinical, radiological, or microbiological differences were found between the three groups. No association was found between the level of the microgap and the amount of bone loss.

CONCLUSIONS

The results of this study indicate that dental implants designed for a submerged implantation procedure can also be used in a non-submerged procedure and may be as predictable as when used in a submerged procedure or as one-piece implants. The microgap at the crestal level in two-piece implants does not appear to have an adverse effect on the amount of peri-implant bone loss.

Recovery of periodontopathogenic bacteria from embalmed human cadavers

There is recent interest in recovery of periodontopathogenic bacteria from arterial and bronchial tissues to identify a link between periodontal and cardiovascular or pulmonary diseases. This interest could provide a useful clinical correlation exercise for gross anatomy. Our objective was to perform a feasibility study to determine whether these bacteria could be recovered from two sites within eight (4 dentate, 4 edentulous) human embalmed cadavers from an anatomical dissection laboratory. Bacterial samples were collected from the right coronary artery and the right superior secondary bronchus and assayed for the presence and concentrations of the DNA of A. actinomycetemcomitans, E. corrodens, C. rectus, P. intermedia, P. gingivalis, B. forsythus, T. denticola, and F. nucleatum. Frequencies were compared using a Kruskal-Wallis H-test. Correlations between the presence of teeth, bacterial species, and site were determined by a Spearman's rho correlation test. A. actinomycetemcomitans and B. forsythus frequencies were different between the sites in edentulous subjects (P <0.05); the frequency of B. forsythus was different in dentate and edentulous subjects at the bronchus site (P <0.05). Numerous significant correlations were identified between strains of bacteria, site, and presence of teeth. Thus, it is possible for the DNA of periodontopathogenic bacteria to be recovered from human embalmed cadavers. Collection and identification of these bacteria from these cadavers could be a useful clinical correlation exercise for dental students in a gross anatomy class.

Two-part implants inserted in a one-stage or a two-stage procedure. A prospective comparative study

OBJECTIVE

The aim of this study was to evaluate the feasibility of using a two-part implant system in a one-stage procedure and to monitor the microflora in the peri-implant area in relation to clinical and radiographic outcome.

MATERIAL AND METHODS

After randomisation, 40 edentulous patients (Cawood & Howell class V-VI) received two IMZ implants in the anterior mandible inserted by either a one-stage (n = 20) or a two-stage (n = 20) surgical procedure for overdenture treatment. A standardised clinical and radiographic evaluation was performed after denture insertion as well as 6 and 12 months thereafter. Twelve months after loading, peri-implant samples were collected and analysed for the presence of putative periodontal pathogens using culture technique.

RESULTS

No striking differences were found between the two groups with regard to the clinical parameters during the evaluation period. The mean bone loss in the first year of functioning was 0.6 mm in both groups. With regard to the gingiva score, plaque score, bleeding score or bone loss between T0 and T12, no associations were found with the presence of the cultured microorganisms. An association was present between pockets >or= 4 mm and the presence of Peptostreptococcus micros in the two-stage group.

CONCLUSIONS

The short-term results indicate that two-part implants inserted in a one-stage procedure may be as predictable as inserted in the common two-stage procedure. The peri-implant sulcus can and does harbour potential periodontal pathogens without significant signs of tissue breakdown.

Two-stage IMZ implants and ITI implants inserted in a single-stage procedure. A prospective comparative study

The aim of this study was to evaluate the feasibility of using a two-stage implant system in a single-stage procedure and to study the impact of the microgap at crestal level and to monitor the microflora in the peri-implant area. Forty edentulous patients (Cawood & Howell class V-VI) participated in this study. After randomisation, 20 patients received two IMZ implants inserted in a single-stage procedure and 20 patients received two ITI implants. After 3 months, overdentures were fabricated, supported by a bar and clip attachment. A standardised clinical and radiographic evaluation was performed immediately after denture insertion and 6 and 12 months later. Twelve months after loading, peri-implant samples were collected with sterile paper points and analysed for the presence of putative periodontal pathogens using culture techniques. One IMZ implant was lost due to insufficient osseointegration. With regard to the clinical parameters at the 12 months evaluation, significant differences for plaque score and probing pocket depth (IMZ: mean 3.3 mm, ITI: mean 2.9 mm) were found between the two groups. The mean bone loss in the first year of functioning was 0.6 mm for both groups. Prevotella intermedia was detected more often in the ITI group (12 implants) than in the IMZ group (three implants). Porphyromonas gingivalis was found in three patients. In one of these patients an implant showed bone loss of 1.6 mm between T0 and T12. Some associations were found between clinical parameters and the target microorganisms in the ITI group. These associations were not present in the IMZ group. The short-term results indicate that two-stage implants inserted in a single-stage procedure may be as predictable as one-stage implants. The microgap at crestal level in nonsubmerged IMZ implants seems to have no adverse influence on the peri-implant microbiological colonisation and of crestal bone loss in the first year of functioning. The peri-implant sulcus can and does harbour potential periodontal pathogens without signs of peri-implantitis during the evaluation period of 1 year.