Socio-demographic and area-related factors associated with the prevalence of caries among preschool children in Greece.

OBJECTIVE: To assess dental caries experience in 4-6 year old children of the Athens Metropolitan Area attending public kindergartens and investigate the association of area deprivation and immigration status on dmft. BASIC RESEARCH DESIGN: A cross-sectional study of a large area-stratified sample of 683 kindergarten children was conducted during the academic years 2009-2011. Dental caries experience and oral hygiene level were assessed using dmft and the Simplified Debris index (DI-s). Area deprivation was defined using a pre-established Geo-demographic System for Attica. Zero-inflated Poisson regression models were used to test associations between the dmft index and related factors; gender, age, immigrant background and area deprivation. Differences were reported in terms of predicted probabilities. RESULTS: Caries prevalence was 20.8% (95% CI17.8,24.0%). The mean dmft and DI-s scores were 0.67 (95% CI0.61,0.74) and 0.16 (95% CI0.14,0.18) respectively. The mean predicted probability of having no detectable caries experience was 79% (95% CI75, 83%), while the probability of having dmft=1 or 2 was 6% (95% CI5,8%) and 2% (95% CI1,3%) respectively. The predicted probability of having no caries experience was substantially lower for males, those from the least affluent areas and non-Greeks by 5%, 18% and 31% respectively. Regarding dmft scores, deprived children were more likely to have 1 or 2 teeth with caries experience by 9% (95% CI4,13%) and 6% (95% CI2,10%) respectively, while the corresponding differences for non-Greeks were 10% (95% CI7,14%) and 12% (95% CI7,15%). CONCLUSIONS: Socio-demographic and area-related variations in oral health exist among kindergarten children in Athens.

The autoimmunity-oral microbiome connection.

To date, there is a major effort in deciphering the role of complex microbial communities, especially the oral and gut microbiomes, in the pathogenesis of various diseases. Increasing evidence indicates a key role for the oral microbiome in autoimmune diseases. In this review article, we discuss links of the oral microbiota to a group of autoimmune diseases, that is, Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), Crohn's disease (CD), and rheumatoid arthritis (RA). We particularly focus on factors that affect the balance between the immune system and the composition of microbiota leading to dysbiosis, loss of tolerance and subsequent autoimmune disease progression and maintenance.

A comparison of a new alcohol-free 0.2% chlorhexidine oral rinse to an established 0.2% chlorhexidine rinse with alcohol for the control of dental plaque accumulation.

OBJECTIVES: To compare the clinical efficacy of two formulations (alcohol and alcohol free) of 0.2% chlorhexidine (CHX) rinses on plaque, gingivitis and discoloration of teeth. METHODS: This double-blind crossover study consisted of one group of 10 volunteer dental students that followed two 21-day experimental gingivitis test periods. During these periods, the subjects abstained from oral hygiene except for the oral rinse provided. The study started after an initial two-week preparation programme that included a professional prophylaxis and repeated oral hygiene instructions. This was repeated for the 14-day washout period between the two rinses, including prophylaxis as per the first stage of the study. A calibrated examiner performed the clinical measurements at the beginning (baseline) and end of each study stage. The presence and amount of plaque were recorded using the Silness and Löe plaque index (PI) and gingival inflammation by the gingival index (GI) while the discoloration index (DI) was recorded on the buccal and lingual surfaces of the six anterior teeth of both the mandible and maxilla. RESULTS: Mean PI increased similarly for both solutions; however, the differences between initial and final values were statistically significant only for CHLOREL® . Similarly, the mean values for the GI showed small increases over the course of the study periods, but not statistically significant for either solution. The mean DI increased significantly for both solutions. Regarding the comparison of the initial and final values ​​between the solutions, per index, no statistically significant differences were observed. CONCLUSION: The non-alcoholic chlorhexidine rinse had comparable levels of action as the generally recognized gold standard alcoholic rinse.

Oral health related quality of life of Greek adolescents: a cross-sectional study.

AIM: To investigate the impact of oral health status on the quality of life of a cross-section of adolescents belonging to different population groups in different regions of Greece, using the oral health impact profile-short form (OHIP-14), one of the most widely known instruments used for the measurement of disability and discomfort due to oral conditions. METHODS: A random sample consisting of a total of 515 Greek adolescents between the ages of 15-18 years (mean 16.1±0.9) were selected from different urban and rural areas according to the last census. A self-administrated questionnaire was designed including the OHIP-14 validated for the Greek language, and face to- face interviews were conducted by one dentist trained in oral health related quality of life (OHRQoL) terms. Associations of the total OHIP-14 score and its seven subscales along with the self-perceived quality of life were evaluated with Spearman correlations. RESULTS: Internal reliability returned a very good internal consistency with a Cronbach alpha of 0.86. The subjects had an overall weighted OHIP-14 score of 1.24 (SD 2.04) meaning that there was an impact of oral health on the overall quality of life. Five of the seven subscales of the OHIP-14 tool were found to have significant correlations for the inhabitants of the different areas. Specifically, important and significant correlations were discovered for functional limitation (p<0.01), handicap (p<0.05) and social disability (p<0.01) both for the metropolitan/non-metropolitan as well as the urban rural distinction. No correlations were found between the OHIP-14 scores, or of any of its sub-scales, with the parental education level and occupation. When self-assessed oral and general health statuses were considered to be 'bad' the OHIP-14 returned increased scores. CONCLUSIONS: Dental and oral health conditions are factors that do impact on the quality of life of adolescents.

The microbiota on different oral surfaces in healthy children.

INTRODUCTION: Knowledge of the early oral colonization patterns could provide a better understanding of oral biofilm development and disease initiation that in turn could be the basis for early preventive programmes. METHODS: Microbial samples were collected from five different oral habitats from a total of 93 children (age 3-12 years), attending the Dental School of the University of Athens, who were split into three age groups. A total of 38 microbial species were sought out by the checkerboard DNA-DNA hybridization technique. RESULTS: All of the test species, except Parvimonas micra and Porphyromonas gingivalis, differed significantly among sample locations providing quite distinct microbial profiles for the different oral surfaces. Supragingival and subgingival plaque had similar profiles and exhibited higher proportions of Actinomyces species and Green complex while soft tissue samples were dominated by streptococci of the Yellow complex. The profiles of the tongue dorsum and saliva were also similar. Many of the species were in similar proportions in all three age groups for a given location. Periodontal pathogens showed increases in proportions with increasing age. Specifically, the Red complex species (Tannerella forsythia, P. gingivalis, Treponema denticola) showed a significant increase in proportion with age (P < 0.05) in all sample locations. CONCLUSIONS: The results showed a pattern of colonization in children similar to that previously found in adults. Differences in the profile between age groups suggest a gradual maturation of the oral microbiota, with it being made up of an increasing number of Orange and Red complex species.

Contamination of a toothbrush with antibacterial properties by oral microorganisms.

OBJECTIVES: The aim of this study was to examine the contamination and the survival rate of periodontopathic and cariogenic species on new toothbrushes with antibacterial properties (coated bristles with triclosan), after a single use in periodontitis patients. The decontamination effect of the use of toothpaste was also evaluated. METHODS: Ten patients, who consulted the Department of Periodontology, for treatment of chronic periodontitis, were selected. In each patient four different toothbrushes were used. Two quadrants, randomly selected, were each brushed using a different antibacterial toothbrush. In one of these two quadrants toothpaste was used. The same happened with the remaining quadrants, only with regular toothbrushes. After brushing, the toothbrushes were rinsed and stored in room temperature and a dry environment. After 0, 4 and 24h, four tufts, from each toothbrush, were cut and processed for selective and non-selective culturing techniques, followed by identification and quantification of all species found. RESULTS: Immediately after brushing the toothbrushes harbored a significant number of microorganisms, with no statistically significant difference between the two types of brushes (regular and antibacterial). The reduction of microorganisms from 0 to 4h after brushing was statistically significant (p<0.05). The difference was less obvious from 4 to 24h. When toothpaste was used, brushes harbored significantly (p<0.05) lower numbers of colony-forming units (CFU) compared to those without the use of toothpaste. CONCLUSIONS: The antibacterial toothbrush with triclosan coated tufts failed to limit the bacterial contamination. The toothpaste, on the other hand, significantly reduced the contamination of toothbrushes.

Adhesion of Porphyromonas gingivalis to cultured pocket epithelium: mono- and multi-layered.

Adhesion of bacteria to epithelial cells might be influenced by the degree of cell differentiation, as observed in the multi-layering process of epithelial cells. In the present study, the adhesion of a large group of clinical Porphyromonas gingivalis strains (n=11) to in vitro cultured mono- and multi-layers of epithelial cells was examined and compared. The tissue samples originated from 6 patients with chronic adult periodontitis. Porphyromonas gingivalis bacteria adhered more to mono-layers as opposed to the more differentiated multi-layers. Differences between the clinical P. gingivalis strains, however, became obvious only on multi-layers. These partially differentiated cells may also better represent the individual subject variations. Mono-layer cultures, which are simpler to obtain, seem to be less precise. The importance of cell differentiation on bacterial adhesion needs more attention.

Contamination of interdental brushes by periodontopathogens.

Experimental studies have shown that intraoral transmission of bacteria can occur. Of course, the question arises as to how this transmission may happen. In this study, the contamination of interdental brushes by periodontopathogens is examined and compared to the microbial load of the periodontal pockets. In ten untreated chronic periodontitis patients, four interdental sites were professionally brushed with one interdental brush per patient. Subsequently, samples from the depths of the pockets (of the specific interdental sites) were obtained with paper-points. The interdental brush samples and the samples of the subgingival plaque, obtained by the pooled paper-points, were processed for dark-field microscopy examination as well as anaerobic culturing. The results showed that, although significant differences could be found between the brushes and paper-points with direct microscopy, the culturing did not uncover many differences. On the contrary, the detection frequencies of specific bacterial species were almost the same between the two. The total anaerobic colony-forming units (CFU), P. gingivalis, F. nucleatum, and E. corrodens found on the brushes showed a significant correlation with the subgingival plaque samples (P<0.005). These results suggest that, in untreated situations, interdental brushes are contaminated relatively easily by putative periodontopathogens in numbers comparable to their presence in periodontal pockets. This contamination could be a factor in the intraoral spread of bacteria.

Adhesion of Porphyromonas gingivalis strains to cultured epithelial cells from patients with a history of chronic adult periodontitis or from patients less susceptible to periodontitis.

BACKGROUND: The present study aimed to explain the interindividual variation in periodontitis susceptibility by differences in the initial adhesion rate of Porphyromonas gingivalis to the pocket epithelium of these individuals, and/or by inter-P. gingivalis strain differences in association capacity (adhesion and internalization). METHODS: Adhesion assays were performed on epithelial monolayers (cultured in vitro from pocket epithelium belonging to patients who were less or more susceptible to chronic adult periodontitis) using 11 genetically different clinical strains of P. gingivalis. RESULTS: Both the disease category (less susceptible versus susceptible) and the interstrain variation were found to have a significant effect (both P <0.05) on the initial bacterial association. The chronic adult periodontitis group showed significantly more association of P. gingivalis when compared to less susceptible patients (4.2 x 10(6) versus 3.5 x 10(6)). Also, the interstrain variation was significant, with strains Pg 4 and 5 representing the least and best associating bacteria (1.8 x 10(6) colony forming units for Pg 4, 9 x 10(6) for Pg 5). CONCLUSIONS: These results indicate that periodontitis susceptibility is influenced by both the interindividual differences in pocket epithelium (allowing more adhesion of P. gingivalis) or by the strain type by which the patient is infected (intra-species differences in adhesion capacity).

Comparison of fluorescence microscopy and culture assays to quantitate adhesion of Porphyromonas gingivalis to mono- and multi-layered pocket epithelium cultures.

BACKGROUND: The present study compared 2 different methods (direct versus indirect evaluation) for the quantification of the adhesion of Porphyromonas gingivalis strains to in vitro cultured mono-layers of pocket epithelium. METHODS: The indirect culture viability assay (calculation of colony forming units) was compared to a direct microscopic evaluation using a novel fluorescent stain. The fluorescent kit was found to stain both bacteria and epithelial cells and enabled a differentiation between dead and living cells. RESULTS: Comparing the visual to the culture data, a high and significant correlation was found (Pearson's correlation = 0.75; P <0.001). The adhesion capacity was in general higher for dead epithelial cells than for living cells (P <0.01). Although comparable numbers of bacteria of 2 P. gingivalis strains (Pg 4 and Pg 5) were applied, Pg 4 showed a significantly lower adhesion capacity. This intra-strain variability was observed by the culture assay (2.3 x 10(6) versus 7.8 x 10(6)+/-2.7 x 10(6); P <0.01) and by the direct microscopy (P <0.01) for both live and dead epithelial cells. A second goal was to see whether there was a difference in the amount of bacterial adherence to mono- and multi-layers of in vitro cultured epithelium. No significant differences were found for the 5 examined P. gingivalis strains. However, interstrain differences in adhesion capacity were evident for both tissues. CONCLUSIONS: This study highlights the reproducibility of a direct microscopic evaluation of bacterial adhesion to in vitro cultured epithelial cells, and suggests both intrastrain (P. gingivalis) and inter-cell (live versus dead) variation in adhesion capacity. Studies are needed to determine the extent to which P. gingivalis strain variation is reflected in variation of other strains in humans.

Multi-layered periodontal pocket epithelium reconstituted in vitro: histology and cytokeratin profiles.

BACKGROUND: In order to study inter-individual differences in bacterial adhesion/invasion of periodontal tissues, an in vitro model for culturing multi-layered pocket epithelium without feeder layers or stromal equivalents (including the evaluation of their cytokeratin profiles) was developed. METHODS: Pocket epithelium was collected and grown until confluent in Falcon flasks using keratinocyte-serum free medium (KSFM), without a feeder layer. In the second passage, oral keratinocytes were re-grown in a 2 compartment system using either a clear polyester (transwell-clear [TCL]) or a collagen (transwell-col [TCO]) membrane as culture surface. After the first week, the calcium concentration was raised to 1.2 mM and in half the wells, the KSFM was supplemented with 10% fetal calf serum (FCS). Histology and immunohistochemistry were performed after 1, 2, and 3 weeks of additional growth. RESULTS: In general, all conditions resulted in a structured epithelium consisting of 3 to 5 layers, but important differences were observed between the membrane types and between the media. CK4 was rarely and only lightly expressed while CK18 and 19 (characteristic of junctional epithelium) were very strongly expressed in the older (2 and 3 weeks) cultures. CK13 and 14 (characteristic of any stratifiable epithelial cell) also tended to increase over time; CK13 seemed to be stronger in KSFM with FCS while the contrary was true for CK14. The multi-layer created by the combination TCL/KSFM + 10% FCS resembled a junctional epithelium most, while that grown on TCO without FCS mimicked the sulcular epithelium. CONCLUSIONS: It seems possible to create a histiotypic culture resembling either periodontal pocket or junctional epithelium without the use of stromal equivalents or feeder layers which make this approach more cumbersome. This multi-layered culture offers a model to investigate the permeability of pocket epithelium and the adhesion and penetration of bacteria under well-defined environmental conditions.

Adherence of Peptostreptococcus micros morphotypes to epithelial cells in vitro.

Peptostreptococcus micros, which is associated with oral and non-oral mixed anaerobic infections, occurs in three colony morphotypes, the smooth type, the rough type and the smooth variant of the rough type. These types differ in surface structures; the rough type expresses large fibrillar surface appendages, which are absent on the surface of both the smooth and the smooth variant of the rough type. To determine the role of these surface structures in adherence we characterized the adherence of the three morphotypes of P. micros to epithelial cells in vitro. Although all three types adhered well to epithelial cells, adhering numbers of the rough type were significantly lower than those of the smooth and the smooth variant of the rough type. Protease treatment increased the adherence of the rough type of the level of the two other types. The adherence of all three types was reduced more than 85% by treatment with 10 mM sodium periodate. Furthermore, the adherence was pH independent and could not be blocked by incubation with antisera to the bacteria. In addition, we determined the capacity to invade epithelial cells by P. micros. In an acridine orange assay such invasion could not be detected. Our results suggest that the adherence of P. micros to epithelial cells is mediated by periodate-sensitive extracellular polysaccharides and that the protruding fibril-like protein surface structures of the rough type have an obstructive effect on the adherence.

The effect of a one-stage full-mouth disinfection on different intra-oral niches. Clinical and microbiological observations.

A treatment for periodontal infections often consists of consecutive rootplanings (per quadrant, at a 1- to 2-week interval), without a proper disinfection of the remaining intra-oral niches (untreated pockets, tongue, saliva, mucosa and tonsils). Such an approach, could theoretically lead to a reinfection of previously-treated pockets. The present study aims to examine the effect of a full-mouth disinfection on the microbiota in the above-mentioned niches. Moreover, the clinical benefit of such an approach was investigated. 16 patients with severe periodontitis were randomly allocated to a test and a control group. The patients from the control group were scaled and rootplaned, per quadrant, at 2-week intervals and obtained oral hygiene instructions. The patients from the test group received a full-mouth disinfection consisting of: scaling and rootplaning of all pockets in 2 visits within 24 h, in combination with tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with a 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. Besides oral hygiene, the test group rinsed 2x daily with 0.2% chlorhexidine and sprayed the tonsils with a 0.2% chlorhexidine for 2 months. Plaque samples (pockets, tongue, mucosa and saliva) were taken at baseline and after 2 and 4 months, and changes in probing depth, attachment level and bleeding on probing were reported. The full-mouth disinfection resulted in a statistically significant additional reduction/elimination of periodontopathogens, especially in the subgingival pockets, but also in the other niches. These microbiological improvements were reflected in a statistically-significant higher probing depth reduction and attachment gain in the test patients. These findings suggest that a disinfection of all intra-oral niches within a short time span leads to significant clinical and microbiological improvements for up to 4 months.

One-stage full-mouth disinfection to overcome intra-oral transmission of periodontopathogens.

The oral cavity offers a range of different niches where periodontopathogens can adhere and survive (e.g. the mucosa, the tongue, the tonsils, the saliva and all intra-oral hard surfaces such as teeth, dentures, oral implants). Transmission of bacteria from one niche to another is likely to occur. Recent studies, for example, illustrated that initially sterile abutments of oral implants were rapidly colonized by bacteria from the subgingival environment around teeth. This transmission of bacteria can occur spontaneously via the saliva, or by means of oral hygiene aids and/or dental instruments. Such an intra-oral transmission, if it occurs at a high speed, could jeopardize the outcome of periodontal therapy. To overcome a bacterial transmission, a 'one-stage full-mouth disinfection' was recently introduced for the treatment of periodontal infections. This new treatment strategy resulted in significant clinical and microbiological improvements when compared with the standard sequential treatment.

Complete nose coverage to prevent airborne contamination via nostrils is unnecessary.

Besides an atraumatic procedure, aseptic techniques during surgery have been suggested to have a positive impact on the predictability of osseointegration. To avoid an infection of the surgical field, coverage of the face of the patient (drapes) and nose (surgical mask, drape and plastic film) were advocated in order to reduce airborne infections and to prevent a contact contamination of instruments and gloves. Such a coverage, however, increases the feeling of claustrophobia when local anaesthesia is used and can lead to hypoxemia. The aim of the present study was to investigate whether the expired air via the nostrils could contribute to the contamination of the oral surgical field. Test blood agar plates were installed for 30 min under the nose of volunteers lying on a surgical table; once with full coverage of their nostrils, as indicated above, and once without. Simultaneously, control plates were installed on a table besides the patient to measure the basic contamination from the environment. All plates were incubated both aerobically and anaerobically. The number of colony forming units (c.f.u.) recorded on test plates after aerobic and anaerobic incubation were surprisingly low, with a mean score of 2.7 and 5.0 c.f.u. for the uncovered situation, and 2.5 and 3.3 c.f.u. for the covered situation, respectively. The control plates were infected by a nearly comparable number of bacteria (means ranging from 2.2 to 3.2). These findings indicate that covering nostrils by a mask and sterile adhesive plastic film is not essential in avoiding airborne microbial contamination. However, the use of a meshed nose guard to prevent contact with the highly contaminated nasal skin is highly recommended.

The influence of periodontitis on the subgingival flora around implants in partially edentulous patients.

The hypothesis that teeth act as reservoirs of micro-organisms for the colonization of oral implants has recently been stated several times. The present study aimed at examining, in partially edentulous patients with severe periodontitis, whether pockets around teeth and implants harbored a comparable micro-flora. In 6 patients (3 with refractory periodontitis and 3 with advanced chronic adult periodontitis), plaque samples were taken from a deep and shallow pocket around both teeth and implants for differential phase contrast microscopy and DNA probe analysis. The results showed important differences in the sub-gingival flora between the 2 disease groups, as well as between deep and shallow pockets, around both implants and teeth. On the other hand, when pockets around teeth and implants with equal depths were compared a striking similarity was observed in the microbial composition. These observations confirm the hypothesis that pockets around teeth act as a reservoir and highlight the importance of periodontal health when oral implants are planned.

The adherence of periodontopathogens to periodontal probes. A possible factor in intra-oral transmission?

Periodontal probes have previously been shown to harbor several bacterial types or species after probing periodontally diseased pockets. This study aims to identify and quantify periodontopathogens that may adhere to a periodontal probe by culturing techniques. It also examines the probe's roughness on its capability to collect bacteria, comparing Merrit-B probes (with deep indentations) with TPS probes (with smooth surfaces). From the differential phase contrast microscopy findings it was seen that, while paper-points harbored nearly 50% motile rods or spirochetes, the periodontal probes were just at, or below, the 20% threshold level for pathogenicity (23.6% for the Merrit-B probe and 11.3% for the TPS probe). The cultural data showed that paper-points had significantly higher (P < 0.05) numbers of anaerobic bacteria than the 2 probe types, which still harbored up to 10(7) CFU. No significant differences could be detected between the probes. When specific periodontopathic species were considered, it was seen that for all species, even for Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis, the detection frequency was comparable for the 3 sampling devices. However, the levels of Prevotella intermedia and Campylobacter rectus was significantly higher in samples from paper-points (P < 0.05), but still their numbers reached even 10(5) on the probes. Differences among the 2 probe types were again negligible. Periodontal probes harbor relatively high numbers of bacteria found in periodontal pockets and may be able to carry them over to other sites. Further studies are needed to determine if, and to what extent, transmission occurs during periodontal probing.

Intraoral transmission and the colonization of oral hard surfaces.

The sterile abutments of 2-stage implants offer a unique model to study intraoral transmission and bacterial colonization patterns in the oral cavity. This study aimed to examine, by means of differential phase contrast microscopy, parameters that influence the intra-oral colonization of these abutments. In part one, 159 partially edentulous patients were examined to determine the influence on the microbial composition around implants of the following parameters: 1) the relative location of the teeth in relation to the implants; 2) the microbial composition of the subgingival plaque around these teeth; and 3) the frequency of deep pockets around the natural dentition. The results indicate that the subgingival flora around the implants harbored more spirochetes and motile rods when teeth were present in the same jaw (P < 0.05) and/or when the pockets around them harbored a pathogenic flora (P < 0.05). In part two, the impact of periodontitis around the remaining teeth and of probing depth around the implants on the composition of the peri-implant subgingival flora was investigated. Thirty-one partially edentulous implant patients were classified according to their periodontal condition into 3 groups: healthy (n = 17), chronic periodontitis (n = 11), and refractory periodontitis (n = 3). The samples from deep pockets (> or = 4 mm) around implants showed significant increases in the total proportion of spirochetes and motile organisms when compared to samples from healthy subjects (1.2%) or in chronic periodontitis patients (21.0%), or to patients suffering from refractory periodontitis (31.5%). For shallow pockets (< 4 mm) significant differences were only detected between subjects with a healthy periodontium (1.0%) or chronic periodontitis (2.4%), and refractory periodontitis cases (19.7%). The present findings confirm the transmission of microorganisms from teeth to implants, and thereby highlight the importance of periodontal health around the natural dentition before as well as after implant installation.

Full- versus partial-mouth disinfection in the treatment of periodontal infections. A pilot study: long-term microbiological observations.

A standard periodontal treatment consists of 4 to 6 scalings and rootplanings at a 1- to 2-week interval, which allows reinfection of a previously disinfected area before completion of the treatment. The present pilot study aims to examine the microbiological long-term effects of a full-mouth disinfection. 10 patients with advanced chronic periodontitis were randomly allocated to a test and control group. The patients from the control group received scaling and rootplaning and oral hygiene instructions at a 2-week interval. The full-mouth disinfection (test group) consisted of a full-mouth scaling and rootplaning in 2 visits within 24 h in combination with: tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. The patients of the test group were instructed to rinse 2x daily with 0.2% chlorhexidine. Plaque samples were taken at baseline and after 1, 2, 4 and 8 months. Differential phase-contrast microscopy showed a significantly larger reduction of spirochetes and motile organisms in the test group up to month 2 for the single-rooted and up to month 8 for the multi-rooted teeth. Furthermore, the culture data supported the effectiveness of the new treatment strategy. In both groups, the number of anaerobic CFU decreased 1 log around single- and 0.5 log around multi-rooted teeth. The number of anaerobic CFU remained low in the test group, in contrast to the control group. At 1 month, the test group harboured a significantly (p<0.01) lower proportion of pathogenic organisms, but this difference disappeared with time. Moreover, the test sites showed a significantly higher (p<0.02) increase in the proportion of beneficial micro-organisms up to 4 months. These findings suggest that a full-mouth disinfection leads to a significant microbiological improvement up to 2 months, which could be consolidated, although not significant, for the next 6 months.

The influence of titanium abutment surface roughness on plaque accumulation and gingivitis: short-term observations.

The roughness of intraoral hard surfaces plays an important role in bacterial adhesion and colonization. Earlier studies have shown that rough surfaces accumulate up to 25 times more subgingival plaque than do smooth sites. In the present study, the influence of surface smoothing was studied. In six partially edentulous patients waiting for a fixed prosthesis supported by endosseous titanium implants, four titanium abutments with different surface roughness were randomly placed. After 1 month of intraoral exposure, subgingival plaque samples from each abutment were compared within each patient by means of differential phase-contrast microscopy. After 3 months, supragingival and subgingival plaque samples were taken from all abutments for differential phase-contrast microscopy and culturing. Probing depth, recession, and bleeding upon probing were scored at the same visit. Differential phase-contrast microscopy showed that subgingivally, only the two roughest abutments harbored spirochetes after 1 month. After 3 months, subgingivally, the composition of the flora showed little variation on the different abutment types, although spirochetes were only noticed around the roughest abutments. Anaerobic culturing resulted in comparable amounts of colony-forming units for all abutment types, both supragingivally and subgingivally. Subgingivally, the microbiologic composition did not show major interabutment differences. Clinically, small differences in probing depth were observed. The roughest abutment showed some attachment gain (0.2 mm) during 3 months, whereas all other abutments had an attachment loss ranging from 0.8 to greater than 1 mm. The results indicate that a reduction in surface roughness (less than a roughness of 0.2 micron) had no major effect on the microbiologic composition, supragingivally or subgingivally. These observations indicate the existence of a threshold roughness below which no further impact on the bacterial adhesion and/or colonization should be expected. However, clinical evaluation seems to indicate that a certain surface roughness is necessary for increased resistance to clinical probing.