Microbiological and host-derived biomarker evaluation following non-surgical periodontal therapy with short-term administration of systemic antimicrobials: secondary outcomes of an RCT.

Nonsurgical periodontal therapy with adjunctive use of systemic antimicrobials (for 7-14 days) showed improved clinical, microbiological and immunological results over the mechanical protocol alone. Considering the increasing risk for antimicrobial resistance with longer antibiotic regimes, it is important to establish the optimal antibiotic protocol with a maximum antimicrobial benefit and minimum risk for adverse effects. The aim of the study was to evaluate the microbiological and inflammatory outcomes 12-months after a 3-/7-day systemic antibiotic protocol [amoxicillin (AMX) + metronidazole (MET)] adjunctive to subgingival debridement in severe periodontitis compared to mechanical treatment alone. From the initially treated 102 patients, 75 subjects (Placebo group: n = 26; 3-day AMX + MET group: n = 24; 7-day AMX + MET group: n = 25) completed the 12-month examination. Clinical parameters, eight periodontal pathogens and inflammatory markers were determined at baseline and 3-, 6-, 12-months after therapy using real-time PCR and ELISA respectively. After 6 months, several periodontopathogens were significantly more reduced in the two antibiotic groups compared to placebo (p < 0.05). After 1 year, both antibiotic protocols showed significant reductions and detection of the keystone pathogen P. gingivalis compared to placebo. Antibiotic protocols, smoking, disease severity, baseline-BOP, -CAL and -IL-1ß, as well as detection of T. denticola at 12-months significantly influenced the residual number of deep sites. The present data indicate that the systemic use of both short and longer antibiotic protocols (AMX + MET) adjunctive to nonsurgical periodontal therapy lead to higher microbiological improvements compared to subgingival debridement alone. The two investigated antibiotic protocols led to comparable microbiological and inflammatory results.

Prevalence of Candida albicans and Candida dubliniensis in caries-free and caries-active children in relation to the oral microbiota-a clinical study.

OBJECTIVES: The correlation between caries and the oral prevalence of Candida spp. in children is contradictory in literature. Thereby, authors focused on Candida albicans as the most isolated Candida species from the oral cavity. Therefore, the aim of the present study was to compare caries-free and caries-bearing children regarding their oral carriage of Candida spp. MATERIAL AND METHODS: Twenty-six caries-free (CF group) and 26 caries-active children (CA group) were included into this study. Three different types of specimens were assessed, saliva and plaque, and in the case of caries, infected dentine samples were microbiologically analyzed for aerobic and anaerobic microorganisms and their counts. Special attention was given to the differentiation between C. albicans and Candida dubliniensis. Additionally, different biochemical tests, VITEK 2 (VITEK®2, bioMérieux, Marcy-l'Etoile, France) and 16S and 18S ribosomal DNA (rDNA) sequencing, were applied for identification. RESULTS: The detection of C. albicans did not differ between the CF and CA groups. C. dubliniensis was never detected in any specimen of the CF group, but occurred in one quarter of the CA group (27 % in plaque, 23 % in saliva), thus leading to a statistically significant difference between the two groups (p < 0.05). In six of these cases, C. dubliniensis was detected concomitantly in saliva and plaque and once only in plaque. CA group harbored statistically more Streptococcus mutans than the control group revealing a correlation between S. mutans and C. dubliniensis regarding the caries group. CONCLUSIONS: This is the first study reporting a frequent detection of C. dubliniensis in caries-active children, which could have been underestimated so far due to difficulties in differentiation between this yeast species and C. albicans. CLINICAL RELEVANCE: Microbiological diagnostic-especially of oral Candida species-is an important determinant for identifying etiological factors of dental caries in children.

Assessment of viable periodontal pathogens by reverse transcription quantitative polymerase chain reaction.

BACKGROUND AND OBJECTIVE: Molecular biological methods for the detection of periodontitis-associated bacteria based on DNA amplification have many advantages over classical culture techniques. However, when it comes to assessing immediate therapeutic success, e.g. reduction of viable bacteria, DNA-based polymerase chain reaction is unsuitable because it does not distinguish between live and dead bacteria. Our objective was to establish a simple RNA-based method that is easily set up and allows reliable assessment of the live bacterial load. MATERIAL AND METHODS: We compared conventional quantitative real-time PCR (qPCR), propidium monoazide-qPCR and reverse transcription qPCR (RT-qPCR) for the detection of periodontal pathogens after antibiotic treatment in vitro. Applicability was tested using clinical samples of subgingival plaque obtained from patients at different treatment stages. RESULTS: The bacterial load was remarkably stable over prolonged periods when assessed by conventional qPCR, while both propidium monoazide intercalation as well as cDNA quantitation showed a decline according to decreasing numbers of viable bacteria after antibiotic treatment. Clinical samples of subgingival plaque were directly subjected to DNase I treatment and RT without previous extraction or purification steps. While the results of the DNA- and RNA-based methods are comparable in untreated patients, the classical qPCR frequently detected substantial bacterial load in treated patients where RT-qPCR no longer indicates the presence of those pathogens. The disagreement rates ranged between 4 and 20% in first visit patients and 8-50% in the group of currently treated patients. CONCLUSION: We propose to use RNA-based detection methods to verify the successful eradication of periodontal pathogens.

The plaque and gingivitis reducing effect of a chlorhexidine and aluminium lactate containing dentifrice (Lacalut aktiv) over a period of 6 months.

AIM: The aim of the study was to determine the plaque and gingivitis reducing effect of a dentifrice containing chlorhexidine and aluminium lactate compared with a control toothpaste during the course of 6 months. MATERIAL AND METHODS: This randomized, double-blind study looked prospectively at participants over a 6-month period. Plaque, gingivitis, calculus formation and tooth staining were assessed in 59 participants, who were divided into parallel groups. The participants used either a chlorhexidine and aluminium lactate-containing toothpaste (test group) or a minus active control toothpaste (control group). Parameters were assessed at baseline and again after 1, 3 and 6 months. RESULTS: After 6 months of product use, both groups had less gingivitis compared with the baseline evaluation (p<0.001). At this time point, the test group showed a statistically significant lower gingival index values compared with the control group (p=0.001). No statistically significant differences between either the groups or time points were detected with regard to plaque index and the development of calculus and staining. CONCLUSION: Although there was a statistically significant difference at 6 months between test and control groups, this difference was too small to be considered clinically meaningful.

Individual vitality pattern of in situ dental biofilms at different locations in the oral cavity.

The aim of the study was to examine the three-dimensional vitality structure of dental biofilms grown simultaneously at different locations in the oral cavity over a 48-hour period. Eight healthy volunteers wore special acrylic appliances. On each buccal side of the upper and the lower jaw three glass slabs were inserted, allowing for growth of a biofilm mimicking approximal plaque. After 48 h, the specimens were removed and biofilms were stained using two fluorescent dyes which selectively stain vital bacteria green and dead bacteria red. Under the confocal laser scanning microscope optical sections of 1 microm throughout the biofilm were made. To assess the vitality values (proportion of vital bacteria) of the whole biofilm as well as the vitality distribution in the different plaque sections an image analysis program was used. Plaque from the different locations revealed mean vitality values between 64.4 and 75.7% in the upper jaw and between 64.3 and 76.8% in the lower jaw, which were not statistically different. However, a great variation of the vitality values for the different layers and among the 8 subjects was found. Nevertheless, the analysis of the data of each single volunteer revealed a very similar vitality pattern in all twelve locations.

Impact of the intraoral location on the rate of biofilm growth.

The aims of the present study were: a) to assess the impact of the intraoral location on the rate of biofilm growth, and b) to establish an in vivo biofilm model to examine intraoral biofilm growth. Eight healthy volunteers wore acrylic splints with 15 glass slabs each in the upper and lower jaws to build up plaque. After 48 h, the specimens were removed and stained using the vital fluorescence technique. Biofilm thickness was evaluated by confocal laser scanning microscopy (CLSM). The mean plaque thickness amounted to 77.6 +/- 29.1 microm on the buccal sites of the upper jaw and 71.9 +/- 26.3 microm on the buccal sites of lower jaw. On the palatal site a biofilm of 52.1 +/- 26.2 microm thickness was grown, which was significantly less compared with the other locations evaluated (p < 0.001). The results demonstrate that the in situ biofilm thickness on the buccal sites was similar irrespective of the location in the oral cavity. The new splint system described may be a useful tool for further standardised experimental studies regarding influences on growth and structure of intraoral biofilms.

Effect of an enamel matrix protein derivative (Emdogain) on ex vivo dental plaque vitality.

BACKGROUND: A common clinical observation following surgical periodontal therapy with an enamel matrix derivative (Emdogain) is the improved healing of the soft tissues and the limited inflammation of the operated areas. These clinical observations are empirical and difficult to explain. One of the factors influencing the early wound healing might be a potential antimicrobial effect of Emdogain. AIM: To investigate the effect of Emdogain on the vitality of ex vivo supragingival dental plaque and to compare this effect to that of a standard 0.2% chlorhexidine solution. MATERIALS AND METHODS: 24 patients suffering from adult periodontitis were included in the study. At the beginning of the experiment, all participants were given a professional tooth cleaning. For the following 4 days, they had to refrain from any kind of oral hygiene measures. At day 5, from each of the volunteers, a voluminous plaque biofilm sample was taken with a sterile curette from the vestibular surfaces of the 1st lower molars and divided into 5 equal parts. Each part was mounted with 5 microl of the following solutions: (1) NaCl, (2) enamel matrix derivative dissolved in water (EMD), (3) enamel matrix derivative dissolved in the vehicle (Emdogain), (4) vehicle (propylene glycol alginate, PGA), (5) 0.2% chlorhexidine digluconate (CHX). After a reaction time of 2 min the test solutions were sucked off, and subsequently the biofilm was stained with a fluorescence dye. The vitality of the plaque flora after the treatments was evaluated under the fluorescence microscope (VF%). RESULTS: Plaque samples treated with NaCl showed a mean vitality of 76.8+/-8%. The EMD, Emdogain, PGA and CHX showed VF values of 54.4+/-9.2, 21.4+/-10.6%, 19.6+/-11.6% and 32.3+/-11.8%, respectively. Emdogain, PGA and CHX showed statistically highly significant reductions (p<0.0001) in terms of bacteria vitality when compared to water (negative control) and EMD. Both Emdogain and PGA were found to be statistically significantly different compared to CHX (p<0.001) (positive control). CONCLUSION: The results of this study indicate that Emdogain might have an antibacterial effect on the vitality of the ex vivo supragingival dental plaque flora.

Spatial distribution of vital and dead microorganisms in dental biofilms.

To examine the spatial structure of dental biofilms a vital fluorescence technique was combined with optical analysis of sections in a confocal laser scanning microscope (CLSM). Enamel slaps were worn in intraoral splints by three volunteers for five days to accumulate smooth-surface plaque. After vital staining with fluorescein diacetate and ethidium bromide the specimens were processed for CLSM examination. Optical sections 1 microm apart were analysed in the z-axis of these dental biofilms. One of the films was 15 microm high, sparse and showed low vitality, i.e. <16%, while the others were taller (25 and 31 microm) and more vital, i.e. up to 30 and 69%, respectively. In all instances the bacterial vitality increased from the enamel surface to the central part of the plaque and decreased again in the outer parts of the biofilm. The spatial arrangement of the microorganisms in the biofilm showed voids outlined by layers of vital bacteria, which themselves were packed in layers of dead material.

Alcohol-free mouthrinse solutions to reduce supragingival plaque regrowth and vitality. A controlled clinical study.

BACKGROUND: The aim of this study was to evaluate the clinical and antibacterial properties of alcohol-free mouthrinses, an amine fluoride/stannous fluoride mouthrinse (ASF) and two triclosan solutions in comparison with a chlorhexidine and a placebo rinse. MATERIAL AND METHODS: In a double-blind, randomised 5-cell cross-over 4-day plaque regrowth study, 19 volunteers rinsed 2 x a day with 15 ml of each of the distributed solutions. Each test cycle was followed by a 10 days wash-out period. On day 0 of each test week, volunteers received a dental prophylaxis. Thereafter they refrained from all mechanical oral hygiene procedures for the next four days. Plaque regrowth was assessed daily by the plaque index and on day 4 by calculating the plaque area with a computer program after disclosure and photography of the front teeth. The vitality of the plaque was examined on days 1 to 4 by the vital fluorescence technique. RESULTS: 19 participants completed the study. Compared to the placebo the ASF solution showed 15.7% (p>0.5), 30.6% (p<0.001), 40.5% (p<0.001) and 44.7% (p<0.001) reductions on the consecutive days 14 in plaque index and a reduction of 61.9% in plaque area. The decrease of vitality of supragingival plaque was highly significant compared to placebo on every test day ranging between 30.9% and 36.6%. A reduction in plaque index from 19.4% (p<0.01) on day 2, 34.9% (p<0.001) on day 3 and 40.4% (p<0.001) on day 4 concommitant with a reduction in plaque area of 48.9% (p<0.001) was noted for alcohol-free chlorhexidine. Concerning the vitality chlorhexidine reduced the percentage of vital bacteria significantly on every day (16.0% to 24.9%). The reductions in mean plaque index for the 0.15% triclosan solution during the test period were 6.3%, 22.4%, 24.6% and 36% and in plaque area 41.8%. Vitality was significantly reduced at every day compared to placebo. Plaque Index reduction with the 0.02% triclosan increased from 15.3% (day 2) to 31.0% (day 4) and a reduction of 23.6% was seen in plaque area. A significant effect concerning the vitality of the plaque was only found at the first and the last day of the test cycle. CONCLUSION: Alcohol-free mouthrinse solutions were shown to be effective in reducing both plaque accumulation and plaque biofilm vitality compared to a placebo solution.

Does pretreatment of cavities effectively promote good marginal adaptation of glass-ionomer cements?

PURPOSE: The aim of this laboratory study was to evaluate the marginal sealing ability of four glass-ionomer cements in cervical restorations (Class V) using dye penetration. Two conventional (C-GIC) and two resin-modified (RM-GIC) cements were used either with or without dentin conditioning with polyacrylic acid. MATERIALS AND METHODS: 96 cervical cavities of standardized size were prepared in vitro in the vestibular and lingual portions at the cementoenamel level of 48 premolars. The coronal margins were prepared in enamel, the apical margins were localized in dentin. The 96 cavities were randomly divided into 4 groups of n = 24 each. The cavities of each group were filled with one of the test materials, and only half of the cavities received a dentin conditioning for 20 s with polyacrylic acids before filling. The fillings were finished with a set of abrasive disks 24 h after setting. The restored teeth were stored in saline for 4 weeks and subjected to dye penetration. The depth of dye penetration along the coronal and apical margin was measured on 4 longitudinal sections of each tooth with a semi-automatic image analysis system at 40x magnification. RESULTS: Mean depth of dye penetration ranged from 0 (ChemFil superior without conditioner) to 0.13 mm (ChemFil superior with conditioner) at enamel sites, and from 0.02 (Fuji II LC with conditioner) to 0.74 mm (ChemFil superior with and without conditioner) at dentin sites. CONCLUSION: The conditioning of the cavities before filling improved the marginal adaptation significantly only in the Ketac-Fil group. Conventional glass-ionomer cements (C-GIC) in general demonstrated a lower sealing ability than the light-activated, resin-modified cements (RM-GIC). The adaptation of Photac-Fil quick is best without pretreatment--as recommended by the manufacturer.

Clinical and antibacterial effect of tea tree oil--a pilot study.

The aim of this clinical pilot study was to compare the effect of tea tree oil with the effect of water and chlorhexidine on supragingival plaque formation and vitality. Eight subjects were asked to refrain from any kind of mechanical oral hygiene for 4 days after professional tooth cleaning (day 0), and to rinse with water instead for 1 week, with chlorhexidine in a second and tea tree oil in a third test week. The plaque index (PI), which was evaluated daily (days 1-4), served as a clinical control parameter. On the last day of the study (day 4), the plaque covering the front teeth was stained, photographed, and therefrom the plaque area (PA; %) was estimated using a digital measuring system. Each day of the study (days 1-4), the sampled plaque was examined using a vital fluorescence technique. Tea tree oil reduced neither the clinical parameters (PI and PA) nor the vitality of the plaque flora significantly. Within the limitations of the study design, it was determined that a solution with tea tree oil--utilized as ordinary mouthwash--has no positive effect on the quantity or quality of supragingival plaque.