Short-term effects of systemic antibiotics during periodontal healing

OBJECTIVES: To investigate the short-term effects of nonsurgical therapy (scaling and root planing, SRP) on the subgingival microbiota in chronic (CP) and aggressive (AP) periodontal disease. METHOD AND MATERIALS: Ninety-seven CP and AP subjects underwent full-mouth SRP on 2 consecutive days. AP patients were randomly assigned to either receive systemic metronidazole plus amoxicillin (AP+AB) or were treated mechanically alone (AP). Pathogens were identified with 16S rRNA oligodeoxynucleotide probes and dot-blot hybridization before and at days 2, 3, 4, 7, 10, and 21 of healing. CP subjects were treated by scaling and root planing along with placebo tablets. RESULTS: Initially, AP cell counts were 69.9- (Porphyromonas gingivalis), 10.2- (Aggregatibacter actinomycetemcomitans), 5.7- (Tannerella forsythia), and 3.3-fold (Prevotella intermedia) enhanced compared to CP cell counts. Following SRP, immediate elimination occurred in single individuals of all three treatment groups at day 2. After SRP plus antibiotic therapy (AP+AB), the prevalence scores dropped beyond the levels of AP and CP, beginning at day 7, and remained low until day 21 (P =or< .05). Clinical healing statistically benefited from SRP with no differences among the three treatment groups. CONCLUSION: Nonsurgical therapy resulted in both a suppression and early elimination of single taxa immediately after completion of active treatment. Systemic antibiotics significantly accelerate the suppression of the periodontal microflora, but have limited effect on the elimination of target isolates during healing.

Hyaluronic Acid as an Adjunct After Scaling and Root Planing - A Prospective Randomized Clinical Trial

Aim: The study was designed to determine the effect on clinical variables, subgingival bacteria and local immune response brought about by additional application of hyaluronan-containing gels in early wound healing after scaling and root planing (SRP). Material and Methods: In this randomised clinical study, data from 34 individuals with chronic periodontitis was evaluated after full-mouth SRP. In the test group (n = 17), hyaluronan gels in two molecular weights were additionally applied during the first two weeks after SRP. The control group (n = 17) was treated with SRP only. Probing depth (PD) and attachment level (AL) were recorded at baseline and after 3 and 6 months, and subgingival plaque and sulcus fluid samples were taken for microbiological and biochemical analysis. Results: In both groups, PD and AL were significantly reduced (p < 0.001). The changes in PD and the reduction of the numbers of pockets with PD ≥ 5mm were significantly higher in the test group after 3 (p = 0.014; p = 0.021) and 6 months (p = 0.046; p = 0.045). Six months after SRP, the counts of Treponema denticola were significantly reduced in both groups (both p = 0.043), those of Campylobacter rectus in the test group only (p = 0.028). Prevotella intermedia and Porphyromonas gingivalis increased in the control group. Conclusions: The adjunctive application of hyaluronan may have positive effects on probing depth reduction and may prevent recolonization by periodontopathogens.

A systematic review of the effects of full-mouth debridement with and without antiseptics in patients with chronic periodontitis

OBJECTIVES: To assess the clinical and microbiological effects of full-mouth debridement with (FMD) and without the use of antiseptics [full-mouth scaling and root planing (FMSRP)] in comparison with conventional staged debridement (CSD) in patients with chronic periodontitis after at least 6 months. MATERIAL AND METHODS: The search in MEDLINE (PubMed), covering a period of 1975 to October 2007, and hand searching yielded 207 titles. Forty-two abstracts and 17 full-text articles were screened for inclusion. RESULTS: Twelve articles allowed a direct comparison of FMD with CSD, FMSRP with CSD and FMD with FMSRP. Probing pocket depth reductions were significantly greater (0.2 mm) with FMD and FMSRP compared with CSD. Moreover, a modest reduction in BOP (9%) favoured FMD. Likewise, clinical attachment levels were improved by 0.2-0.4 mm in favour of FMD and FMSRP, respectively. In all comparisons, single-rooted teeth and deep pockets benefitted slightly from FMD and FMSRP. Limited differences in the changes of the subgingival microbiota were noted between the treatment modalities. CONCLUSIONS: Despite the significant differences of modest magnitude, FMD or FMSRP do not provide clinically relevant advantages over CSD. Hence, all three treatment modalities may be recommended for debridement in the initial treatment of patients with chronic periodontitis.

Multi-scale micro-structure generation strategy for up-scaling transport in clays

Clays and claystones are used as backfill and barrier materials in the design of waste repositories, because they act as hydraulic barriers and retain contaminants. Transport through such barriers occurs mainly by molecular diffusion. There is thus an interest to relate the diffusion properties of clays to their structural properties. In previous work, we have developed a concept for up-scaling pore-scale molecular diffusion coefficients using a grid-based model for the sample pore structure. Here we present an operational algorithm which can generate such model pore structures of polymineral materials. The obtained pore maps match the rock’s mineralogical components and its macroscopic properties such as porosity, grain and pore size distributions. Representative ensembles of grains in 2D or 3D are created by a lattice Monte Carlo (MC) method, which minimizes the interfacial energy of grains starting from an initial grain distribution. Pores are generated at grain boundaries and/or within grains. The method is general and allows to generate anisotropic structures with grains of approximately predetermined shapes, or with mixtures of different grain types. A specific focus of this study was on the simulation of clay-like materials. The generated clay pore maps were then used to derive upscaled effective diffusion coefficients for non-sorbing tracers using a homogenization technique. The large number of generated maps allowed to check the relations between micro-structural features of clays and their effective transport parameters, as is required to explain and extrapolate experimental diffusion results. As examples, we present a set of 2D and 3D simulations and investigated the effects of nanopores within particles (interlayer pores) and micropores between particles. Archie’s simple power law is followed in systems with only micropores. When nanopores are present, additional parameters are required; the data reveal that effective diffusion coefficients could be described by a sum of two power functions, related to the micro- and nanoporosity. We further used the model to investigate the relationships between particle orientation and effective transport properties of the sample.

The effects of erythritol air-polishing powder on microbiologic and clinical outcomes during supportive periodontal therapy: Six-month results of a randomized controlled clinical trial.

OBJECTIVES To characterize the physical characteristics of a new low abrasive erythritol powder (EPAP) and to evaluate its influence on the clinical and microbiologic parameters over a period of 6 months in patients undergoing supportive periodontal therapy (SPT). METHOD AND MATERIALS Prior to the clinical application, the particle size and abrasion level of EPAP were compared to glycine air-polishing powder (GPAP) ex vivo. Subsequently, 40 chronic periodontitis patients previously enrolled in SPT were randomly assigned into two groups for the treatment with subgingival EPAP or repeated scaling and root planing (SRP). At baseline (BL), bleeding on probing positive (BOP+) sites with probing pocket depth (PPD) of ≥ 4 mm but no detectable calculus were defined as study sites. During SPT, these sites were either treated by EPAP or SRP at BL, 3, and 6 months (3M, 6M). When indicated, additional SRP was provided. Plaque Index, BOP, PPD, clinical attachment level (CAL), and subgingival plaque were evaluated at BL and 6M. RESULTS EPAP yielded lower abrasiveness and smaller particle sizes when compared to GPAP. In 38 patients completing the study, EPAP and SRP resulted in significant reductions of BOP% (EPAP, 40.45%; SRP, 42.53%), PPD (EPAP, -0.67; SRP, -0.68), and increase of CAL (EPAP, 0.48; SRP, 0.61) while at 6M no statistically significant between-group differences were observed (P > .05). Microbiologic evaluation revealed minor shifts in the composition of the subgingival biofilm without influence on periodontopathogenic bacteria. CONCLUSION The subgingival use of EPAP by means of an air-polishing device may be considered safe and may lead to comparable clinical and microbiologic outcomes to those obtained with SRP. CLINICAL RELEVANCE The subgingival use of EPAP appears to represent a promising modality for the removal of subgingival biofilm during SPT.