Jörg Eberhard

Full‐mouth treatment concepts for chronic periodontitis: a systematic review

OBJECTIVES To systematically review the effectiveness of full-mouth treatment concepts for chronic periodontitis. MATERIAL AND METHODS A search was conducted for randomized, controlled clinical trials including full-mouth scaling with (FMD) or without (FMS) the use of antiseptics and quadrant scaling (control). Data sources included COHG, CENTRAL, MEDLINE and EMBASE. Reviewers independently conducted data abstraction and quality assessment. The primary outcome was tooth loss; secondary outcomes were the reductions of PPD and BOP and a gain of CAL. RESULTS Of 216 identified abstracts, seven trials were included. Meta-analysis revealed a weighted mean difference (WMD) for the reduction of PPD between FMD and control of 0.53 mm [95% confidence interval (CI) (0.28, 0.77), p<0.0001] in moderately deep pockets of single-rooted teeth. The WMD for gain in CAL was 0.33 mm [95% CI (0.04, 0.63), p=0.03] in moderately deep pockets of single- and multi-rooted teeth. Comparing FMD and FMS, the WMD for the reduction of CAL amounted to 0.74 mm [95% CI (0.17, 1.31), p=0.01] in deep pockets of multi-rooted teeth in favour of FMS. For BOP a WMD -18.0% [95% CI (-34.30, -1.70), p=0.03] was calculated in deep pockets of single-rooted teeth in favour of FMD. CONCLUSIONS In adults with chronic periodontitis only minor differences in treatment effects were observed between the treatment strategies.

Evaluation of selective caries removal by a fluorescence feedback-controlled Er:YAG laser in vitro

Aim: To establish a fluorescence threshold level that could guide a therapeutic Er:YAG laser through a caries lesion to determine a therapeutic endpoint of caries removal. Materials and Methods: A total of 65 extracted human teeth, 35 with dentine caries and 30 healthy, were used for this study. An Er:YAG laser system that emitted at a wavelength of 2.94 µm was used. The laser was equipped with a laser fluorescence feedback system, excitation wavelength 655 nm, to control the irradiation by the Er:YAG laser. The evaluated threshold levels of the fluorescence feedback system were 3, 7, 8, 10, 12, 15 and 20. After treatment the teeth were prepared for histological staining according to the method of Brown and Brenn for the identification of bacteria. The specimens were subjected to a quantitative evaluation of residual bacteria on the treated dentine surface. In addition, the internal fluorescence of dentine and potential fluorescence changes of dentine after laser irradiation were evaluated. Results: About 80% of the irradiated dentine surface showed residual bacteria with threshold levels of 20, 15, 12, and 10. Residual bacteria were not found with threshold levels of 7 and 3. The study revealed a significant increase in dentine fluorescence after laser irradiation. Conclusion: The results of the present in vitro study indicate that a fluorescence threshold level of 7 or 8 units can guide an Er:YAG laser to a complete removal of carious dentine.

Calculus removal and the prevention of its formation

Periodontitis is strongly associated with the presence of dental calculus on root surfaces. Although the rough calculus surface may not in itself induce inflammation in the adjacent periodontal tissues, dental calculus serves as an ideal substrate for subgingival microbial colonization. Therefore, causerelated anti-infective therapy aims to eliminate the microbial biofilm and calcified deposits from the diseased root surfaces by means of root surface debridement. Over the past 50 years, a large number of clinical and laboratory studies have been performed to determine the efficacy of calculus removal from diseased root surfaces by various methods. These studies aimed to determine whether complete removal of subgingival calculus by root surface debridement is possible. They also evaluated the importance of operator experience in the effectiveness of calculus removal. Possible differences in efficacy between hand tools and power-driven instruments or lasers have been investigated. The impact of tooth and site characteristics, such as probing depths, tooth type, tooth surfaces and furcation areas, has also been evaluated. In addition, side-effects such as unintentional root substance removal and patient discomfort have been assessed. This review focuses on the composition and formation of calculus, its significance for the disease process, the methods available for calculus removal, and prevention of its formation.

The stage of native biofilm formation determines the gene expression of human β‐defensin‐2, psoriasin, ribonuclease 7 and inflammatory mediators: a novel approach for stimulation of keratinocytes with in situ formed biofilms

BACKGROUND/AIMS Antimicrobial peptides such as human beta-defensin-2 (hBD-2), psoriasin (PSO), and ribonuclease 7 (RNase 7) play an important role in innate immunity. The aim of the present study was to test the hypothesis that epithelial cells show a differential gene expression pattern of antimicrobial peptides (hBD-2, PSO, RNase 7) and inflammatory mediators such as interleukin-8 (IL-8) and 5-lipoxygenase (5-LO) in response to different stages of naturally formed biofilms. METHODS Epithelial cells were cultured from biopsies obtained from five healthy individuals. Native bacterial biofilms were taken from the same subjects that donated the gingival biopsies. To obtain different stages of biofilm formation, polymer disks were attached to prostheses and carried intraorally for 1, 3, 5, and 9 days. The expression of genes for hBD-2, PSO, RNase 7, 5-LO, and IL-8 was examined using semi-quantitative reverse transcription-polymerase chain reaction. The bacterial composition of the individual biofilms was defined using a microarray system (Parocheck), which showed the presence of 20 different bacterial species that are associated with plaque formation. RESULTS The expression of the messenger RNAs of hBD-2, RNase 7, and 5-LO was upregulated as a result of the exposure to early biofilm stages, whereas the gene expression of IL-8 was increased in response to matured biofilms. Inter-individual differences in the innate immune response were observed. CONCLUSION The results of the present study showed a time-dependent messenger RNA expression of antimicrobial peptides (hBD-2, RNase 7), 5-LO, and IL-8 in oral epithelial cells responding to different stages of biofilm formation.

Fluorescence‐controlled Er:YAG laser for caries removal in permanent teeth: a randomized clinical trial

The aim of this randomized clinical study was to compare the efficacy of a fluorescence-controlled erbium-loaded yttrium aluminum garnet (Er:YAG) laser with conventional bur treatment for caries therapy in adults. Twenty-six patients with 102 carious lesions were treated using either the Er:YAG laser, at threshold levels of 7, 8, 9, and 10 [U], or rotary burs. Both techniques were applied to each lesion at separate locations. After treatment, dentine samples were obtained using a carbide bur. The viable counts of Streptococcus mutans (SM) and lactobacilli (LB) [expressed as colony-forming units (log10 CFUs)], treatment time, pain, vibration, and sound intensity were determined. The median numbers of CFUs for SM and LB were not statistically different between laser and bur treatment at threshold levels 7 and 8 [U]. At threshold levels 9 and 10 [U], the median number of CFUs for LB [1.11 (range: 0.00-2.04)] were significantly higher following laser treatment than following bur treatment [0.30 (range: 0.00-0.60)]. The results indicate that treatment with a fluorescence-controlled Er:YAG laser at threshold levels of 7 and 8 removed caries to a level similar to that achieved using conventional bur treatment, with clinically irrelevant amounts of remaining bacteria. Although more time consuming, laser treatment provided higher patient comfort than bur treatment.

Probiotics affect the clinical inflammatory parameters of experimental gingivitis in humans

Objectives:To determine the effects of a probiotic milk drink consumed over a period of 28 days, regarding the expression of clinical inflammatory parameters of the oral gingiva during various phases of plaque-induced gingivitis.Methods:Twenty-eight adults with healthy gingiva took part in a prospective and clinical-controlled study. The test group was advised to consume a probiotic milk drink (Yacult) daily during a period of 4 weeks; the control group did not receive any probiotic food or drink. After 2 weeks of consumption of the probiotic drink, participants were advised not to brush their teeth for 14 days. Subsequently, at baseline as well as on days 1, 3, 5, 7 and 14, the following clinical parameters were assessed: plaque index (PI), gingival index (GI), gingival crevicular fluid (GCF) volume and bleeding on probing (BOP).Results:At baseline, the PI was significantly higher in the test group compared with controls (0.44±0.50 vs 0.09±0.24 PI; P=0.0001). The termination of oral hygiene increased clinical inflammatory parameters in both groups. At day 14, the parameters PI, GI, GCF volume and BOP were significantly higher compared with baseline values (P=0.0001). At day 14, BOP levels (18.75±12.32 vs 36.88±12.54%) and GCF volume (18.78±16.7 vs 35.72±16.1 Periotron units) were significantly lower in the test group compared with the control group (P=0.005).Conclusion:The results of our study indicate that a daily consumption of a probiotic milk drink reduces the effects of plaque-induced gingival inflammation associated with a higher plaque score due to the high-carbohydrate content of the probiotic milk beverage.

Laser fluorescence measurements compared to electrical resistance of residual dentine in excavated cavities in vivo.

It has been suggested that laser fluorescence close to the dental pulp shows higher values than more distant measurements. The aim of this study was to assess fluorescence on the cavity floor and to correlate these measurements with electrical resistance as a measure of residual dentine thickness. Thirty carious lesions were excavated with a bur. The endpoint of caries removal was determined by visual, tactile and auditory means. Fluorescence was measured with the Diagnodent device and with the fluorescence feedback system of a therapeutic Er:YAG laser. Electrical resistance of the residual dentine (Prepometer units, PU) was measured with a proprietary device. Significant differences were observed between the fluorescence systems (p < 0.05). For Diagnodent, a decrease of electrical resistance of the residual dentine resulted in an increase of the fluorescence values of 2.99 units/PU (95% CI = 2.00–3.97) and an increase of 0.30 units/PU (95% CI = 0.19–0.40) for the fluorescence feedback system. For zero electrical resistance, a predicted maximum value of 51.5 units (95% CI = 41.3–61.7) was calculated for the Diagnodent and 5.1 units (95% CI = 4.1–6.2) for the feedback system. The study indicates that using the suggested detection cut-off with the Diagnodent device may be not suited to assess the endpoint of caries removal close to the dental pulp. Employing the Key Laser III, values up to 6 units might be caused solely by close proximity to the pulp, which should be considered when caries removal by laser is controlled by laser fluorescence feedback.

Cavity size difference after caries removal by a fluorescence-controlled Er:YAG laser and by conventional bur treatment.

To determine the extensions of cavities prepared conventionally by bur or by a fluorescence-controlled Er:YAG laser. Sixty-five human teeth with dentine caries were bisected through the caries lesion and were treated by a fluorescence-controlled Er:YAG laser in a non-contact or a contact mode or by a rotary bur. The specimens were subjected to histological staining and a quantitative evaluation of cavity area (mm2) by computer-assisted alignment. Data were tested for statistical significant differences by the Wilcoxon test (p < 0.05). Twenty-three out of 29 cavities were smaller after caries removal with the non-contact laser compared to the bur. For a threshold level of seven, a cavity size difference of 1.63 (1.86) mm2 was calculated compared to a cavity size difference of 5.35 (5.05) mm2 after bur excavation. The differences were statistically significant (p = 0.029). No significant differences were observed between the cavity size differences after excavation with the non-contact or the contact laser handpiece. Residual bacteria within the cavity floor were found only in low numbers after all treatments. The present in vitro study indicates that caries removal by a fluorescence-controlled Er:YAG laser using a threshold level of seven resulted in less dentine loss than preparations by a bur.

Interaction between periodontal disease and atherosclerotic vascular disease – Fact or fiction?

C-reactive protein (CRP) level is associated with the 10-year risk of an atherosclerotic vascular disease (ASVD), suggesting presence of systemic inflammation probably long before ASVD is present. Where, however, does this systemic inflammation come from? One active area of research has been the study of dental infection and various forms of periodontal disease (PD), both of which are highly prevalent in populations at risk for ASVD. Recent data show that ASVD and PD interact with each other via systemic release of specific pro- and anti-inflammatory cytokines, small signal molecules and enzymes which modulate initiation and progression of the chronic inflammatory reaction involved in both diseases. In addition, periodontal pathogens were identified within atherosclerotic lesions and thrombi isolated from myocardial infarction patients. LDL cholesterol, a strong risk factor for ASVD, is also associated with PD; and statins, used to treat ASVD, are also active to prevent or reduce PD. Finally, there is growing evidence for common genetic susceptibility factors involved in both diseases. These findings support commonalities with respect to the pathogenic mechanisms involved in both inflammatory diseases. Conversely, a causative relationship cannot yet be concluded in the absence of data from large longitudinal cohort and randomized controlled intervention trials.

Composition of Microbial Oral Biofilms during Maturation in Young Healthy Adults

In the present study we aimed to analyze the bacterial community structure of oral biofilms at different maturation stages in young healthy adults. Oral biofilms established on membrane filters were collected from 32 human subjects after 5 different maturation intervals (1, 3, 5, 9 and 14 days) and the respective phylogenetic diversity was analyzed by 16S rDNA amplicon sequencing. Our analyses revealed highly diverse entire colonization profiles, spread into 8 phyla/candidate divisions and in 15 different bacterial classes. A large inter-individual difference in the subjects’ microbiota was observed, comprising 35% of the total variance, but lacking conspicuous general temporal trends in both alpha and beta diversity. We further obtained strong evidence that subjects can be categorized into three clusters based on three differently occurring and mutually exclusive species clusters.