[Preferred zones of accumulation of prosthetic microbial plaque on removable complete dentures]

INTRODUCTION

Denture plaque (DP) is not visible with naked eye when it is not mineralized or not fully fixed. Describing and studying its qualitative and quantitative aspects in Complete Dentures (CD) require precisely-located sampling but selection criteria have not yet been well defined. In order to improve our treatment and preventive strategies for patients with CD, it is necessary to explore the various DP accumulation zones on CD fitting surfaces.

PURPOSE

The aim of this study is to assess the DP accumulation on fitting surfaces of CD.

MATERIAL AND METHODS

Distribution of DP accumulation zones was assessed by naked eye observation of the fitting surfaces on 31 maxillary and 31 mandibular CD. The prostheses were to be carried regularly since at least one year. The data were collected at the Prosthodontics department of the Annaba University Medical Center in Algeria. Prostheses were immersed for 24 hours in a plaque disclosing solution containing erythrosin 2% (Dento-Plaque Inava). The maxillary fitting surface was divided into five sectors: the post damming zone (1MaxFS), the top of the palate zone (2MaxFS), the incisor zone (3MaxFS), the maxillary tuberosity zone (4MaxFS), and the end of the canine and 1st premolar zone (5MaxFS). For mandibular fitting surfaces: trigonal and retromolar zone (1ManFS), canine and 1st premolar zone (2ManFS), and incisor zone (3ManFS).

RESULTS

DP distribution was found to be homogeneous on the fitting surface of mandibular CD, however it was distributed in unequal way on the maxillary fitting surfaces. We noted a highly significant difference (p < 0.001) in the staining frequencies of the targeted zones. The most colored zone was the post damming one (1MaxFS), with a rate of 96.7%, whereas the least colored zone was the top of palate one (2MaxFS), with 35.5%. On the mandibular fitting surfaces, the rate of staining was 93.5% for the trigonal and retromolar zone (1ManFS) versus 83.8% on canine, 1st premolar (2ManFS) and incisor (3ManFS) zones. There was no significant difference (p = 0.422).

CONCLUSION

The accumulation of DP was found to be homogeneous on mandibular fitting surfaces and no homogeneous on maxillary fitting surfaces. These results require further investigations in order to understand the causes of this difference. This will allow us to improve our treatment and preventive strategies for edentulous patients.

Temporal changes of denture plaque microbiologic composition evaluated in situ

This study assessed how biofilm composition is affected by both time and denture material in complete denture wearers. Biofilm was formed during two phases of 14 days on acrylic resin and denture liner specimens mounted on the buccal surface of the mandibular dentures of 21 patients. Specimens were removed randomly on days 2, 7, and 14. Higher counts of Candida glabrata, total streptococci, Actinomyces, total microorganisms, and percentage of Actinomyces were observed after 7 and 14 days (P < .05). C glabrata was the only species to show progressively rising counts from day 2 to 14, while no difference was found in biofilm composition among the materials tested.

Microbiological and clinical outcomes and patient satisfaction for two treatment options in the edentulous lower jaw after 10 years of function

BACKGROUND

Long-term data on microbiological and clinical outcome as well as on patient satisfaction after implant therapy in the edentulous mandible are limited. Especially comparisons between fixed full prostheses (FFPs) and overdentures (ODs), or between anchoring systems for the latter are scarce.

AIM

This study aimed to evaluate both of these parameters at the 10-year follow-up in a group of fully edentulous patients rehabilitated via an OD or a FFP (the latter to allow inter-group comparison).

MATERIAL AND METHODS

A total of 37 fully edentulous patients (25 ODs, 12 FFPs, age at implant installation ranged from 36 to 85 years) participated in this study. All subjects received their implants (Branemark System, Nobel Biocare AB, Gothenburg, Sweden) 10 years previously. For the ODs different attachment systems (bar, magnets, ball) had been applied that allowed a further intra-group comparison. At the follow-up visit, 10 years after the abutment insertion, a series of periodontal parameters were recorded, long-cone radiographs were taken and subgingival plaque samples were collected for analysis using checkerboard DNA-DNA hybridization. The clinical and radiographic data were recorded at abutment connection and after 1 and 10 years.

RESULTS

After 10 years of loading, mean plaque and bleeding indices and changes in attachment or marginal bone level were not significantly different, neither between the OD and FFP group, nor within the OD group. The marginal bone loss between abutment connection and year 10 was 0.86 and 0.73 mm for OD and FFP groups, respectively. The subgingival microbiota at implant sites from all (sub)-groups was comparable, with low numbers of DNA counts (+/-10 x 10(5)) but high detection frequencies of Actinobacillus actinomycetemcomitans (>90%), Porphyromonas gingivalis (>85%) and Tannerella forsythensis (30%). The composition of the subgingival microbiota was influenced by probing depth and bleeding tendency. Patient satisfaction was very high for both types of prosthetic rehabilitation. The FFP group scored only slightly better for chewing comfort and general satisfaction.

CONCLUSION

These data indicate that from the clinical and microbiological standpoint, as well as patient satisfaction, both an OD and a FFP offer a favourable long-term outcome.