Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries.

AIM: To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach. MATERIALS AND METHODS: Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The country of origin, diagnosis and clinical and demographic variables of the subjects were used to analyse the microbial profiles. RESULTS: In total, 506 subgingival samples were analysed: 196 from HS and 310 from patients with periodontitis. Differences in richness, diversity and microbial composition were observed when comparing samples pertaining to different countries of origin and different subject diagnoses. Clinical variables, such as bleeding on probing, did not significantly affect the bacterial composition of the samples. A highly conserved core of microbiota associated with periodontitis was detected, while the microbiota associated with periodontally HS was much more diverse. CONCLUSIONS: Periodontal diagnosis of the subjects was the main variable explaining the composition of the microbiota in the subgingival niche. Nevertheless, the country of origin also had a significant impact on the microbiota and is therefore an important factor to consider when describing subgingival bacterial communities.

Association between smoking and peri-implant diseases: A retrospective study.

OBJECTIVES: To determine the association between tobacco and peri-implant diseases in a sample of patients who had received implant-supported restorations in a university dental clinic. Furthermore, the study aimed to investigate patient- and implant-related variables associated with peri-implant diseases. MATERIALS AND METHODS: The present retrospective study analyzed data from 117 patients treated with implant-supported restorations from 2001 to 2013. A total of 450 implants were evaluated. Patients were selected from an electronic database, and patient- and implant-related variables were evaluated. Detailed information regarding the smoking history (i.e., smoking status, lifetime cumulative dose, duration of exposure, intensity of the habit, and smoking cessation) was recorded. The primary study outcome was peri-implant status [i.e., health (H), peri-implant mucositis (PM) and peri-implantitis (PI)]. Univariate and multinomial regression models comparing PM and PI versus peri-implant health were conducted. RESULTS: A total of 117 subjects [55 (47%) females and 62 (53%) males] with a mean age at examination of 64.2 years (SD 11.6) and rehabilitated with 450 implants were included. The average number of implants per patient was 4.6 (SD 3.3) with a mean time in function of 8.0 years (SD 1.9). Fifty-six patients (47.9%) were non-smokers, 42 (35.9%) were former-smokers, and 19 (16.2%) were current-smokers. Thirty-nine subjects (33.4%) were H, whereas 41 (35%) and 37 (31.6%) exhibited PM and PI, respectively. At implant level, the corresponding values were 142 (31.6%), 230 (51.1%) and 78 (17.3%). In the multinomial regression model, significant associations for peri-implant diseases were observed for the mean number of implants per patient (p = .016), function time (p = .048), implants placed simultaneously with guided bone regeneration (p = .016), implant surface (p = .020), keratinized mucosa at the buccal aspect (p = .032), and access to interproximal hygiene (p < .001). In addition, ever smokers >23 pack-years exhibited a significantly higher risk for peri-implantitis (p = .002). Finally, the multinomial regression analysis revealed that subjects who had stopped smoking more than 21 years before the last examination presented a significantly lower risk of peri-implant diseases than a smoking cessation of ≤21 years (p = .028). CONCLUSIONS: Smoke intensity was associated with an increased risk of the development of peri-implantitis. Moreover, the risk of peri-implant diseases might be similar in those subjects who had stopped smoking for more than 21 years with respect to never-smokers.

Is systemic inflammation a missing link between periodontitis and hypertension? Results from two large population-based surveys.

OBJECTIVE: The primary objective was to investigate the relationship between periodontitis and hypertension in two independent large surveys. The secondary objective was to ascertain whether systemic inflammation had a mediation effect in the association. METHODS: This cross-sectional study analysed representative samples of the US (n = 3460; NHANES 2009/10) and Korean (n = 4539; 2015 KNHANES VI-3) populations. The association between periodontitis (exposure), hypertension (outcome) and inflammatory markers [C-reactive protein (CRP) and white blood cell counts (WBC)] (mediators) was assessed using multivariate linear and logistic regression models and mediation analysis. RESULTS: Participants with periodontitis were more likely to have hypertension (NHANES: OR = 1.3, 95% CI: 1.0-1.6, P = 0.025; KNHANES: OR = 1.2, 95% CI: 1.0-1.4, P = 0.041) and actual systolic blood pressure ≥ 140 mmHg (NHANES: OR = 1.6, 95% CI: 1.1-2.3, P < 0.001; KNHANES: OR = 1.3, 95% CI :1.0-1.6, P < 0.031) than those without the disease. These associations were independent of age, gender, BMI, education level, smoking, alcohol consumption, creatinine, physical activity, presence of other comorbidities and confirmed in participants not taking antihypertensive medications. Diagnosis of periodontitis was directly associated with WBC (in both surveys: NHANES: ß ± SE = 0.3 ± 0.1, P < 0.004; KNHANES: ß ± SE = 0.3 ± 0.1, P < 0.001) and with CRP levels (in one survey: NHANES: ß ± SE = 0.1 ± 0.03, P < 0.007; KNHANES: ß ± SE = 0.1 ± 0.04, P > 0.213). Mediation analyses confirmed that CRP acted as a mediator in the association between periodontitis and hypertension in both populations (mediated effect: NHANES: ß ± SE = 0.010 ± 0.003, P < 0.001; KNHANES: ß ± SE = 0.003 ± 0.001, P = 0.015). WBC acted as a mediator in the KNHANES (mediated effect: ß ± SE = 0.004 ± 0.001, P = 0.004) whilst in the NHANES, its effect was dependent of CRP inclusion in the model (mediated effect WBC + CRP: ß ± SE = 0.002 ± 0.001, P = 0.001). CONCLUSIONS: These findings suggest that periodontitis is closely linked to hypertension and systemic inflammation is, in part, a mediator of this association.

Structural and histological differences between connective tissue grafts harvested from the lateral palatal mucosa or from the tuberosity area.

Tuberosity grafts had a greater percentage of lamina propria and lower percentage of submucosa when compared to lateral palate grafts. OBJECTIVE: The study aims to understand the differences in the structural composition of soft tissue autografts harvested from the lateral palate or the tuberosity. MATERIAL AND METHODS: Patients were randomly allocated to receive autografts harvested either from palatal or tuberosity sites to augment horizontal volume deficiencies around single-tooth implants. Tissue biopsies were analyzed for histological and histo-morphometric analysis. Picro-sirius red stain was used to evaluate collagen 1 and 3. Also, immuno-histochemical analysis was performed against MMP1, MMP2, cytokeratin-10, cytokeratin-13, and lysine hydroxylase-2. RESULTS: Twenty specimens were harvested from 9 subjects in the lateral palate group (PG) and 11 subjects in the tuberosity group (TG). The percentage of lamina propria represented 51.08% in the PG group and 72.79% in the TG group, while the area of submucosa was minimal in the TG group representing 4.89% of the total sample vs 25.75% in the PG. The total area of COL-1 and 3 in the TG was 1.19 ± 0.57 and 0.72 ± 0.44 mm2, respectively, while in the PG, the corresponding values were 1.4 ± 0.7 and 1.04 ± 0.5 mm2. The immuno-histochemical analysis generally showed a higher expression of LLH-2, MMP2, CYT-10, and CYT-13 in the TG when compared with the PG. CONCLUSION: Tuberosity grafts had a greater percentage of lamina propria and lower percentage of submucosa. The collagen content in the lamina propria was similar for both groups while the immuno-histochemical profile showed differences in the antibody expression of the epithelial cells. CLINICAL RELEVANCE: Tuberosity grafts had more lamina propria and less submocusa, which may be beneficial for volume augmentation.

Clinical and microbiological evaluation of the effect of Lactobacillus reuteri in the treatment of mucositis and peri-implantitis: A triple-blind randomized clinical trial.

BACKGROUND AND OBJECTIVE: Oral probiotics appear to improve the treatment of periodontal diseases but there is limited evidence on their efficacy in the treatment of peri-implant diseases. The objective of the present study was to evaluate, clinically and microbiologically, the effect of the oral probiotic, Lactobacillus reuteri Prodentis, as adjuvant to non-surgical mechanical therapy in implants with mucositis or peri-implantitis, placed in patients with a history of periodontal disease. MATERIAL AND METHODS: A randomized, controlled, parallel-design, triple-blind prospective clinical study was designed. Patients included in the study were partially edentulous and had implants with mucositis or peri-implantitis. Implants with radiographic bone loss of ≥5 mm and/or ≥50% of the implant length were excluded, and only one implant per patient was included. After non-surgical mechanical therapy, subjects were randomly assigned to take either 1 probiotic lozenge or 1 placebo lozenge every day for 30 days. Clinical measurements were taken in the whole mouth (general plaque index and general bleeding on probing) and at the implant site (probing pocket depth, plaque index and bleeding on probing) at baseline and 30 and 90 days Microbiological examination (to identify Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Campylobacter rectus and Eikenella corrodens) was performed at the same study time points that clinical measurements were made. RESULTS: A total of 44 patients - 22 with mucositis and 22 with peri-implantitis - randomly received treatment with either probiotic or placebo. The probiotic L. reuteri, together with mechanical therapy, produced an additional improvement over treatment with mechanical therapy alone, both in the general clinical parameters of patients with mucositis (bleeding on probing) and at the level of implants with mucositis (probing pocket depth) or peri-implantitis (bleeding on probing and probing pocket depth). However, L. reuteri had a very limited effect on the peri-implant microbiota because the only parameter in which a significant decrease was found was the bacterial load of P. gingivalis in implants with mucositis (P = .031). CONCLUSION: The administration of a daily lozenge of L. reuteri for 30 days, together with mechanical debridement of the whole mouth, improved the clinical parameters of implants with mucositis or peri-implantitis over a period of at least 90 days, but the microbiological effect was much more limited. Probiotics provide an alternative therapeutic approach to consider in the prevention and treatment of peri-implant diseases, but further long-term prospective studies with standardized variables are needed.

Evaluation of root surface microtopography following the use of four instrumentation systems by confocal microscopy and scanning electron microscopy: an in vitro study.

BACKGROUND AND OBJECTIVE: The ideal instrument for initial periodontal therapy should enable the removal of all extraneous substances from the root surfaces without any iatrogenic effects. Because of that the objective of this study is to analyse and to compare the root surface roughness after using Gracey curettes, termination diamond burs (40 µm), a piezo-ceramic ultrasonic scaler and a piezosurgery ultrasonic scaler using confocal microscopy and scanning electron microscopy. MATERIAL AND METHODS: A 2 mm × 2 mm interproximal root area of 20 teeth (n = 40 surfaces) was evaluated by confocal microscopy (×20 magnification) and scanning electron microscopy (×50 to ×1000 magnification). Teeth were randomly assigned to the following four groups: Gracey curettes with 15 vertical strokes; termination diamond burs (40 µm) at 3000 r.p.m.; a piezo-ceramic ultrasonic scaler with a power of 11; and a piezosurgery ultrasonic scaler in mode ROOT with a power of two. RESULTS: Confocal microscopy revealed that curettes [mean changes in the value of surface roughness average reduced by 0.11 ± 0.3], piezo-ceramic ultrasonic scaler (roughness average reduced by 0.47 ± 0.93) and piezosurgery ultrasonic scaler (roughness average reduced by 0.62 ± 0.93) left a smoother surface than termination diamond burs (roughness average increased by 0.39 ± 0.18). Statistically significant differences were observed in roughness (p = 0.005) between piezosurgery and termination diamond burs (p = 0.005). No statistically significant differences were between piezosurgery and Gracey curettes (p = 0.140) and between piezosurgery and piezo-ceramic ultrasonic scalers (p = 0.745). Confocal microscopy and scanning electron microscopy showed that piezosurgery seems to leave the smoothest surface. Surfaces treated with termination burs appear to show more scratches and pits. CONCLUSION: Three of the four instruments tested for root planing reduced surface roughness; however, the piezosurgery ultrasonic scaler produced the smoothest surface. The termination diamond burs (40 µm) produced a rougher surface than the ultrasonic instruments and the hand curettes. Further clinical studies are needed.

Clinical evidence on titanium-zirconium dental implants: a systematic review and meta-analysis.

The use of titanium implants is well documented and they have high survival and success rates. However, when used as reduced-diameter implants, the risk of fracture is increased. Narrow diameter implants (NDIs) of titanium-zirconium (Ti-Zr) alloy have recently been developed (Roxolid; Institut Straumann AG). Ti-Zr alloys (two highly biocompatible materials) demonstrate higher tensile strength than commercially pure titanium. The aim of this systematic review was to summarize the existing clinical evidence on dental NDIs made from Ti-Zr. A systematic literature search was performed using the Medline database to find relevant articles on clinical studies published in the English language up to December 2014. Nine clinical studies using Ti-Zr implants were identified. Overall, 607 patients received 922 implants. The mean marginal bone loss was 0.36±0.06mm after 1 year and 0.41±0.09mm after 2 years. The follow-up period ranged from 3 to 36 months. Mean survival and success rates were 98.4% and 97.8% at 1 year after implant placement and 97.7% and 97.3% at 2 years. Narrow diameter Ti-Zr dental implants show survival and success rates comparable to regular diameter titanium implants (>95%) in the short term. Long-term follow-up clinical data are needed to confirm the excellent clinical performance of these implants.

High prevalence of colonization of oral cavity by respiratory pathogens in frail older patients with oropharyngeal dysphagia.

BACKGROUND: Aspiration pneumonia (AP) is caused by dysfunctional swallowing resulting in aspiration of material colonized by respiratory pathogens. The aim of this study was to assess and compare the swallowing physiology, health status, oral health status, and oral/nasal microbiota in frail older patients (FOP) with oropharyngeal dysphagia (OD) and a control group. METHODS: We studied 47 FOP (>70 year) with OD by videofluoroscopy (17 with acute pneumonia -APN-, 15 with prior pneumonia-PNP- and 15 without) and 14 older controls without OD (H). Oral/nasal colonization by five respiratory pathogens was evaluated by qPCR, whereas commensal microbiota composition was assessed by pyrosequencing. KEY RESULTS: (i) Frail older patients with OD presented similar comorbidities, poor functionality, polymedication, and prevalent videofluoroscopic signs of impaired safety of swallow (33.3-61.5%). However, patients with OD-APN also presented malnutrition, delayed laryngeal vestibule closure (409.23 ± 115.6 ms; p < 0.05), and silent aspirations (15.6%). (ii) Oral health was poor in all groups, 90% presented periodontitis and 72%, caries. (iii) Total bacterial load was similar in all groups, but higher in the oropharynx (>10(8) CFU/mL) than in the nose (<10(6) CFU/mL) (p < 0.0001). Colonization by respiratory pathogens was very high: 93% in OD patients (p < 0.05 vs H); 93% in OD-PNP (p < 0.05 vs H); 88% in OD-APN (p = 0.07 vs H), and lower in controls (67%). CONCLUSIONS & INFERENCES: Frail older patients with OD had impaired health status, poor oral health, high oral bacterial load, and prevalence of oral colonization by respiratory pathogens and VFS signs of impaired safety of swallow, and were therefore at risk for contracting AP.

High-density polytetrafluoroethylene membranes in guided bone and tissue regeneration procedures: a literature review.

Expanded polytetrafluoroethylene (e-PTFE) has been used successfully as a membrane barrier for regeneration procedures. However, when exposed to the oral cavity, its high porosity increases the risk of early infection, which can affect surgical outcomes. An alternative to e-PTFE is non-expanded and dense polytetrafluoroethylene (n-PFTE), which results in lower levels of early infection following surgical procedures. The aim of this literature review was to analyze and describe the available literature on n-PFTE, report the indications for use, advantages, disadvantages, surgical protocols, and complications. The medical databases Medline-PubMed and Cochrane Library were searched and supplemented with a hand search for reports published between 1980 and May 2012 on n-PTFE membranes. The search strategy was limited to animal, human, and in vitro studies in dental journals published in English. Twenty-four articles that analyzed the use of n-PTFE as a barrier membrane for guided tissue regeneration and guided bone regeneration around teeth and implants were identified: two in vitro studies, seven experimental studies, and 15 clinical studies. There is limited clinical and histological evidence for the use of n-PTFE membranes at present, with some indications in guided tissue regeneration and guided bone regeneration in immediate implants and fresh extraction sockets.