Screening of functionalized collagen membranes with a porcine periodontal regeneration model.

OBJECTIVES: Current methods for periodontal regeneration do not promote collagen fiber insertions into new bone and cementum. We used a pig wound model to screen different functionalized collagen membranes in promoting periodontal reattachment to root surfaces. METHODS: Treatment groups included (1) control with no membranes, (2) collagen-coated membranes, (3) membranes with insulin-like growth factor-1 (IGF-1), (4) membranes with amelotin, or (5) membranes attached with calcium phosphate cement (CPC), or with CPC combined with IGF-1. Flap procedures were performed on mandibular and maxillary premolars of each pig. RESULTS: Histomorphometric, micro-CT, and clinical measurements obtained at 4 and 12 weeks after surgery showed cementum formation on denuded roots and reformation of alveolar bone, indicating that the pig model can model healing responses in periodontal regeneration. Calcium phosphate cement simplified procedures by eliminating the need for sutures and improved regeneration of alveolar bone (p < 0.05) compared with other treatments. There was a reduction (p < 0.05) of PD only for the IGF group. Large observed variances between treatment groups indicated that a priori power analyses should be conducted to optimize statistical analysis. CONCLUSIONS: Pigs can model discrete elements of periodontal healing using collagen-based, functionalized membranes. Screening indicates that membrane anchorage with calcium phosphate cements improve regeneration of alveolar bone.

Antibacterial activity of a glass ionomer containing silver nanoparticles against Streptococcus mutans and Streptococcus sanguinis.

AIM: Nano-sized metal particles exhibit special biological, chemical, and physical properties. The aim of this study was to evaluate the effect of incorporating silver nanoparticles into a resin-modified glass ionomer (GI) on its antimicrobial property. MATERIALS AND METHODS: Antibacterial action of GI samples containing 0, 40, 80 ppm silver nanoparticles against standard strains of Streptococcus sanguinis and Streptococcus mutans were assessed by agar diffusion and direct contact tests. Data were analyzed using analysis of variance and Duncan test (P < 0.05). RESULTS: Agar diffusion test showed no bacterial inhibition zone, but direct contact test exhibited significant antimicrobial activity against S. sanguinis and S. mutans in resin containing 80 ppm of nanosilver. CONCLUSION: Incorporation of a certain amount of silver nanoparticles into GI can increase its antimicrobial activity compared to the original material.

Interleukin-17 and interleukin-23 levels in gingival crevicular fluid of patients with chronic and aggressive periodontitis.

INTRODUCTION: Interleukin-17 is a pro-inflammatory cytokine with a wide range of protective and destructive effects in periodontitis. The role of IL-23 is stabilisation and expansion of Th-17. The aim of this study was to assess whether patients with aggressive and chronic periodontitis exhibit different gingival crevicular fluid (GCF) concentrations of IL-17 and IL-23 compared with clinically healthy subjects. MATERIAL AND METHODS: GCF samples were obtained from 32 patients: 10 with chronic periodontitis (CP), 12 with aggressive periodontitis (AgP), and 10 healthy controls (HC). IL-23 and IL-17 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Comparison of study groups was performed with ANOVA and Tukey HSD tests. Spearman's correlation coefficient was used to assess correlations between the variables. RESULTS: IL-17 concentration was significantly higher in the healthy group compared to the AgP and CP groups (p < 0.001), but there were no significant differences between the CP and AgP groups. IL-23 levels in the healthy group were significantly higher than that in the AgP group (p < 0.001). Cytokine concentrations did not correlate significantly with probing depths and clinical attachment levels. CONCLUSIONS: Gingival crevicular fluid concentrations of IL-17 and IL-23 were significantly higher in the healthy group compared to periodontitis groups.

The Effect of Diabetes Mellitus Type I on Periodontal and Dental Status.

INTRODUCTION: Diabetes mellitus type I is a chronic metabolic disease with an autoimmune origin. The initial manifestations mainly appear during childhood and its prevalence is on the rise in many countries. Some of the complications of diabetes mellitus are problems related to oro-dental structures and periodontal diseases. AIM: The present study was undertaken to evaluate the relationship between diabetes mellitus type I and dental and periodontal status in Tehran, Iran. MATERIALS AND METHODS: This cross-sectional study was carried out on 50 patients with diabetes mellitus type I who were under treatment in the Diabetic Patients' Center in Tehran and 50 healthy individuals who did not have diabetes, all recruited from schools. The subjects were divided into two age groups of 6-12 and 13-18 years. In test group, HbA1c (glycosylated haemoglobin) level of the patients was collected from the medical records of Association of Diabetic Patients. To make sure that the control subjects did not suffer from diabetes mellitus, their blood glucose was measured with the Glucocard 01 blood glucose monitoring kit (GT-1920, Japan). The periodontal and dental status were assessed using dmft/DMFT (Decayed, Missing, Filled Permanent Teeth), GI (Gingival Index), PPD (Periodontal Pocket Depth), PI (Plaque Index) and CI (Calculus Index). The data obtained from each group were compared statistically using the Mann-Whitney test and Kruskal Wallis Test. RESULTS: There was increase in PPD, GI and DMFT values with aging, with no significant differences between the diabetic and non-diabetic groups. PI and DMFT not only increased with aging but also were higher in both age groups in patients with diabetes compared to healthy subjects (p<0.05). GI was higher only in the 13-18 year age group in diabetic patients (p<0.01). There was no relation between the HbA1c (glycosylated haemoglobin) level, and periodontal indices (p<0.09). CONCLUSION: It appears that patients with diabetes mellitus type I are more susceptible to periodontal diseases and tooth loss and such problems might be aggravated with aging.

Histologic and histomorphometric evaluation of bone regeneration using nanocrystalline hydroxyapatite and human freeze-dried bone graft : An experimental study in rabbit.

PURPOSE: Bone regeneration is an important concern in periodontal treatment and implant dentistry. Different biomaterials and surgical techniques have been used for this purpose. The aim of the present study was to compare the effect of nanocrystalline hydroxyapatite and human freeze-dried bone graft (FDBG) in regeneration of rabbit calvarium bony defects by histologic and histomorphometric evaluation. METHODS: In this experimental study, three similar defects, measuring 8 mm in diameter, were created in the calvaria of 16 white New Zealand rabbits. Two defects were filled with FDBG and nanocrystalline hydroxyapatite silica gel, while the other one remained unfilled to be considered as control. All the defects were covered with collagen membranes. During the healing period, two animals perished; so 14 rabbits were divided into two groups: half of them were euthanized after 6 weeks of healing and the other half after 12 weeks. The specimens were subjected to histologic and histomorphometric examinations for assessment of the following variables: percentage of bone formation and residual graft material, inflammation scores, patterns of bone formation and type of newly formed bone. RESULTS: The percentages of new bone formation after 6 weeks were 14.22 ± 7.85, 21.57 ± 6.91, and 20.54 ± 10.07% in FDBG, NanoBone, and control defects. These values were 27.54 ± 20.19, 23.86 ± 6.27, and 26.48 ± 14.18% in 12-week specimens, respectively. No significant differences were found in the amount of bone formation between the groups. With regard to inflammation, the control and NanoBone groups showed significantly less inflammation compared to FDBG at the 6-week healing phase (P = 0.04); this difference was not significant in the 12-week specimens. CONCLUSIONS: Based on the results of this experimental study, both NanoBone and FDBG exhibited a similar effect on bone formation.

A randomized controlled evaluation of alveolar ridge preservation following tooth extraction using deproteinized bovine bone mineral and demineralized freeze-dried bone allograft.

BACKGROUND: Alveolar ridge preservation could be performed immediately following tooth extraction to limit dimensional changes of alveolar process due to bone resorption. The aim of this study was to compare the clinical and histologic outcomes of socket preservation using two different graft materials; deproteinized bovine bone mineral (DBBM) and demineralized freeze-dried bone allograft (DFDBA) with absorbable collagen membrane. MATERIALS AND METHODS: Twenty extraction sockets in 20 patients were randomly divided into 2 treatment groups: 10 sockets were augmented with DBBM and collagen membrane whereas 10 sockets were filled with DFDBA and covered by collagen membrane. Primary closure was achieved over extraction sockets by flap advancement. Horizontal and vertical ridge dimensional changes were assessed at baseline and after 4-6 months at the time of implant placement. For histological and histomorphometrical analysis, bone samples were harvested from the augmented sites with trephine during implant surgery. All data were analyzed using SPSS version 18 (α=0.05). RESULTS: Clinical measurements revealed that average horizontal reduction was 2.3 ± 0.64 mm for DFDBA and 2.26 ± 0.51 mm for DBBM. Mean vertical ridge resorption at buccal side was 1.29 ± 0.68 mm for DFDBA and 1.1 ± 0.17 mm for DBBM. Moreover, mean vertical ridge reduction at lingual site was 0.41 ± 0.38 mm and 0.35 ± 0.34 mm for DFDBA and DBBM, respectively. No significant differences were seen between two groups in any of those clinical parameters. Histologic analysis showed statistically significant more new bone deposition for DFDBA compared to DBBM (34.49 ± 3.19 vs. 18.76 ± 3.54) (P < 0.01). Residual graft particles were identified significantly more in DBBM (12.77 ± 1.85) than DFDBA (6.06 ± 1.02). CONCLUSION: Based on the findings of this study, both materials have positive effect on alveolar ridge preservation after tooth extraction, but there was more new bone formation and less residual graft particles in DFDBA group than in DBBM group.

Comparison of Implant Stability Using Resonance Frequency Analysis: Osteotome Versus Conventional Drilling.

OBJECTIVES: Implant primary stability is one of the important factors in achieving implant success. The osteotome technique may improve primary stability in patients with poor bone quality. The aim of this study was to compare implant stability using two different techniques namely osteotome versus conventional drilling in the posterior maxilla. MATERIALS AND METHODS: In this controlled randomized clinical trial, 54 dental implants were placed in 32 patients; 29 implants were placed in the osteotome group and 25 in the conventional drilling group. Implant stability was assessed at four time intervals namely at baseline, one, two and three months after implant placement using resonance frequency analysis (RFA). RESULTS: Primary stability based on implant stability quotient (ISQ) units was 71.4±7 for the osteotome group and 67.4±10 for the control group. There was no statistically significant difference between the two groups in implant stability at any of the measurement times. In each group, changes in implant stability from baseline to one month and also from two months to three months post-operatively were not significant but from one month to two months after implant placement, implant stability showed a significant increase in both groups. CONCLUSION: The results of this study revealed that in both techniques, good implant stability was achieved and osteotome technique did not have any advantage compared to conventional drilling in this regard.

Oral health related quality of life in diabetic patients.

Background and aims. Diabetic patients display an increased risk of oral disorders, and oral health related quality of life (OHRQL) might affect their management and treatment modalities. The aim of the present study was to determine OHRQL and associated parameters in patients with diabetes. Materials and methods. In this study two hundred patients were recruited from the diabetes clinic in Mustafa Khomeini Hospital in Tehran, Iran. OHRQL was assessed using Oral Health Impact Profile Questionnaire (OHIP-20). Also, another questionnaire was designed which contained questions regarding participants' knowledge about oral complications of diabetes and oral health behavior. OHRQL was categorized as low and good. Data were analyzed using logistic regression at P = 0.05. Results. Of the diabetic patients assessed, 77.5% were in good and 22.5% were in low categories of OHRQL. This quality was significantly associated with age (OR = 4.03, 95% CI = 1.63-11.29), knowledge about diabetes oral complications (OR = 18.17 95% CI = 4.42-158.6), educational level (OR = 26.31 95% CI = 4.2-1080.3), referred for dental visit by physician (OR = 3.16 95% CI = 1.48-6.69), frequency of brushing (OR = 10.29 95% CI = 3.96-31.2) and length of time diagnosed with diabetes (OR = 6.21 95% CI = 2.86-13.63). Conclusion. Oral health related quality of life was not negatively affected by diabetes mellitus in the assessed sample.