Indirect caries‐preventive effect of silver diamine fluoride on adjacent dental substrate: A single‐section demineralization study

This study assessed the indirect effect of 38% silver diamine fluoride (SDF) on demineralization of adjacent untreated sound and pre‐demineralized enamel and dentine using a single‐section model for digital transverse microradiography (TMR‐D). Forty‐eight bovine dentine single sections were demineralized, stratified (n = 12) according to integrated mineral loss (ΔZ), and treated with SDF or deionized water (DIW). Each “treated dentine” section was attached between untreated sound and pre‐demineralized enamel or dentine and then subjected to demineralization. ΔZ and lesion depths (LD) of all specimens at baseline, 24 and 48 h demineralization, and after treatment of “treated dentine” were quantified using TMR‐D. Fluoride in the demineralization solution of SDF clusters was determined using an ion‐selective electrode. ΔZ and LD of sound and ΔZ of pre‐demineralized enamel adjacent to SDF‐treated dentine did not increase over time. All untreated dentine demineralized significantly; however, ΔZ of sound dentine adjacent to SDF‐treated specimen was still significantly lower than control. SDF‐treated dentine remineralized and released fluoride even after 48 h. Consistent with clinical findings, when applied only to demineralized teeth in this chemical model, 38% SDF completely inhibited demineralization in adjacent untreated sound enamel. Demineralization prevention was observed to a lesser extent in adjacent pre‐demineralized enamel but not in dentine.     

Potential of Treated Dentin Matrix Xenograft for Dentin-Pulp Tissue Engineering

IntroductionThis study aims to develop and characterize the regenerative potential of an atelopeptidized treated dentin matrix xenograft using in vitro and in vivo models.MethodsFreshly extracted bovine dentin was pulverized into 250- to 500-μm particles and demineralized with 17% EDTA for 1, 7, and 13 days. The samples were atelopeptidized with pepsin. The degree of demineralization and the effect of atelopeptidization were assessed using field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy, respectively. The expression of dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, and osteopontin was evaluated in dental pulp stem cells using quantitative real-time polymerase chain reaction. The samples were then implanted intramuscularly in rats for 30 days, and the inflammatory cells were quantified histologically.ResultsField emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy revealed an exposed tubular structure of dentin after 1 and 7 days of demineralization. Fourier transform infrared spectroscopy confirmed the absence of amide peaks at 1260 to 1640/cm after atelopeptidization. The dental pulp stem cell expression of dentin matrix acidic phosphoprotein 1 and dentin sialophosphoprotein increased in all compared with the untreated control group (P < .05). The maximum expression rates were observed for the 1-day demineralized and atelopeptidized group. The 1-day demineralized group elicited the highest inflammatory response compared with the 7- or 13-day demineralized groups (P < .001). Atelopeptidization significantly decreased the inflammatory response only in the 1-day demineralized dentin group (P < .05).ConclusionsAtelopeptidization of 1-day demineralized dentin xenograft preserved the collagen structure, minimized the immune reaction, and provided sufficient regenerative potential.     

Histologic Healing Following Tooth Extraction With Ridge Preservation Using Mineralized Versus Combined Mineralized‐Demineralized Freeze‐Dried Bone Allograft: A Randomized Controlled Clinical Trial

Background: Mineralized and demineralized freeze‐dried bone allografts (FDBAs) are used in alveolar ridge (AR) preservation; however, each material has advantages and disadvantages. Combinations of allografts aimed at capitalizing on the advantages each offers are available. To date, there is no evidence to indicate if a combination allograft is superior in this application. The primary objective of this study is to histologically evaluate and compare healing of non‐molar extraction sites grafted with either mineralized FDBA or a 70:30 mineralized:demineralized FDBA combination allograft in AR preservation. The secondary objective is to compare dimensional changes in ridge height and width after grafting with these two materials. Methods: Forty‐two patients randomized into two equal groups received ridge preservation with either 100% mineralized FDBA (active control group) or the combination 70% mineralized: 30% demineralized allograft (test group). Sites were allowed to heal for 18 to 20 weeks, at which time core biopsies were obtained and dental implants were placed. AR dimensions were evaluated at the time of extraction and at implant placement, including change in ridge width and change in buccal and lingual ridge height. Histomorphometric analysis was performed to determine percentage of vital bone, residual graft, and connective tissue/other non‐bone components. Results: There was no significant difference between groups in AR dimensional changes. Combination allograft produced increased vital bone percentage (36.16%) compared to the FDBA group (24.69%; P = 0.0116). The combination allograft also had a significantly lower mean percentage of residual graft particles (18.24%) compared to FDBA (27.04%; P = 0.0350). Conclusions: This study provides the first histologic evidence showing greater new bone formation with a combination mineralized/demineralized allograft compared to 100% mineralized FDBA in AR preservation in humans. Combination allograft results in increased vital bone formation while providing similar dimensional stability of the AR compared to FDBA alone in AR preservation.     

Comparison of Peri‐Implant Soft Tissue Parameters and Crestal Bone Loss Around Immediately Loaded and Delayed Loaded Implants in Smokers and Non‐Smokers: 5‐Year Follow‐Up Results

Background: The aim of this study is to compare peri‐implant soft tissue parameters (plaque index [PI], bleeding on probing [BOP], and probing depth [PD] ≥4 mm) and crestal bone loss (CBL) around immediately loaded (IL) and delayed loaded (DL) implants in smokers and non‐smokers. Methods: Thirty‐one patients with IL implants (16 smokers and 15 non‐smokers) and 30 patients with DL implants (17 smokers and 13 non‐smokers) were included. Personal data regarding age, sex, and duration and daily frequency of smoking were gathered using a questionnaire. Peri‐implant PI, BOP, and PD ≥4 mm were recorded, and mesial and distal CBL was measured on standardized digital radiographs. Multiple group comparisons were performed using the Bonferroni post hoc test (P <0.05). Results: All implants replaced mandibular premolars or molars. Mean scores of PI (P <0.05) and PD ≥4 mm (P <0.05) were statistically significantly higher in smokers compared with non‐smokers in patients with IL and DL dental implants. The mean score of BOP (P <0.05) was statistically significantly higher in non‐smokers compared with smokers in both groups. CBL (P <0.05) was statistically significantly higher in smokers compared with non‐smokers in both groups. There was no statistically significant difference in PI, BOP, PD ≥4 mm, and total CBL among smokers with IL and DL implants. Conclusions: Tobacco smoking enhances peri‐implant soft tissue inflammation and CBL around IL and DL implants. Loading protocol did not show a significant effect on peri‐implant hard and soft tissue status in healthy smokers and non‐smokers.     

Salivary osteocalcin levels are decreased in smoker chronic periodontitis patients

Oral Diseases (2011) 17 , 200–205 Objectives: This study was planned to investigate whether smoker chronic periodontitis patients exhibit different salivary concentrations of C‐telopeptide pyridinoline cross‐links of type I collagen (ICTP) and osteocalcin (OC) compared to the non‐smoker counterparts. Methods: Whole saliva samples, full‐mouth clinical periodontal recordings were obtained from 33 otherwise healthy chronic periodontitis patients and 36 systemically, periodontally healthy control subjects. Chronic periodontitis patients and healthy control subjects were divided into smoker and non‐smoker groups according to their self reports. Salivary ICTP, OC levels were determined by Enzyme‐linked Immunoassays. Results: Healthy control groups exhibited significantly lower values in all clinical periodontal measurements (P < 0.001). Smoker periodontitis patients revealed similar clinical periodontal index values with non‐smoker counterparts (P > 0.05). Chronic periodontitis patients exhibited significantly higher salivary OC levels than healthy controls (P < 0.05). Smoker periodontitis patients revealed lower salivary OC levels than non‐smoker counterparts (P < 0.001). Log ICTP levels in non‐smoker chronic periodontitis patients were higher than non‐smoker controls (P < 0.05). Smoker healthy control group revealed higher log ICTP levels than non‐smoker counterparts (P < 0.001). Conclusions: Within the limits of this study, it may be suggested that suppression of salivary osteocalcin level by smoking may at least partly explain the deleterious effects of smoking on periodontal status.     

Effects of Estrogen Deficiency and/or Caffeine Intake on Alveolar Bone Loss,Density, and Healing: A Study in Rats

Background: The aim of this study is to evaluate the effects of caffeine and/or estrogen deficiency on ligature‐induced bone loss (BL), trabecular bone area (TBA), and postextraction bone healing (BH). Methods: Rats were assigned into one of the following groups (15 each): 1) control = non‐ingestion of caffeine/sham surgery; 2) caffeine = ingestion of caffeine/sham surgery); 3) ovariectomized (OVX) = non‐ingestion of caffeine/ovariectomy; or 4) caffeine/OVX = ingestion of caffeine/ovariectomy. The rats were under caffeine administration for 65 days and/or estrogen deficiency for 51 days. On day 21 after ovariectomy, one first mandibular molar received a ligature and the contralateral tooth was not ligated. The first maxillary molars were extracted 8 days before sacrifice. BL, TBA, the positive cells for tartrate‐resistant acid phosphatase (TRAP), receptor activator of nuclear factor‐κB ligand (RANKL), and osteoprotegerin (OPG) were analyzed in the furcation area of mandibular molars. Histometric BH and gene expression of bone morphogenetic protein (BMP)‐2, BMP‐7, osteopontin, and bone sialoprotein were evaluated in alveolar sockets. Results: The caffeine group presented the greatest BL and the OVX group the highest number of TRAP‐positive (TRAP⁺) cells around ligated teeth (P <0.05). The control group presented higher TBA and BH than the other groups (P <0.05). All test groups presented higher RANKL/OPG⁺ cells than the control group around ligated/unligated teeth. The OVX and caffeine/OVX groups presented a greater number of TRAP⁺ cells around unligated teeth than the control group (P <0.05). There were no differences among groups for gene expression (P >0.05). Conclusions: Caffeine increased BL in ligated teeth. Caffeine and/or estrogen deficiency decreased TBA in the unligated teeth and reduced BH after tooth extraction.     

Standardized Rat Model Testing Effects of Inflammation and Grafting on Extraction Healing

Background: Loss of alveolar ridge width and height after tooth extraction is well documented, but models to evaluate ridge preservation are neither standardized nor cost‐effective. This rat model characterizes the pattern of bone turnover and inflammation after extraction and bone grafting with or without local simvastatin (SIM). Methods: Fifty retired‐breeder rats underwent extraction of the maxillary right first molar and standard surgical defect creation under inhalation/local anesthesia. The left side of each animal served as unmanipulated control. Untreated groups (n = 8 to 9 per group) were compared (analysis of variance, t test) at days 0, 7, 14, and 28 for alveolar ridge height and width and for markers of inflammation and bone turnover by microcomputed tomography, histology, and enzyme‐linked immunosorbent assay. Seventeen additional specimens had defects grafted with either bone mineralized matrix (BMM) or a BMM+SIM conjugate. Results: Extraction‐induced bone loss (BL) was noted on buccal, palatal, and interproximal height (P <0.05) and ridge width (P <0.01). Week 1 inflammation positively correlated with ridge height; thereafter, a more intense inflammatory reaction corresponded to reduction in alveolar bone height and density (r = 0.74; P <0.05; Spearman). BMM+SIM preserved the most interproximal bone height (P <0.01), increased ridge width and bone density (P <0.01), enhanced 7‐day prostaglandin E2 (P <0.01), and reduced 28‐day inflammation density (P <0.05). Conclusions: The standard defect used in the current study paralleled human postextraction alveolar BL. Defect grafting, especially BMM+SIM, reduced inflammation and preserved bone.     

Accelerated Bone Formation in Distracted Alveolar Bone After Injection of Recombinant Human Bone Morphogenetic Protein‐2

Background: This study evaluates the effect of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) on the quality and quantity of regenerated bone when injected into distracted alveolar bone. Methods: Sixteen adult beagle dogs were assigned to either the control or rhBMP‐2 group. After distraction was completed, an rhBMP‐2 dose of 330 μg in 0.33 mL was injected slowly into the distracted alveolar crest of the mesial, middle, and distal parts of the alveolar bone in the experimental group. Histologic and microcomputed tomography analyses of regenerated bone were done after 2 and 6 weeks of consolidation. Results: After 6 weeks of consolidation, the vertical defect height in the middle of the regenerated bone was significantly lower in the rhBMP‐2 group (2.2 mm) than in the control group (3.4 mm) (P <0.05). Additionally, the width of the regenerated bone was significantly greater in the rhBMP‐2 group (4.3 mm) than in the control group (2.8 mm) (P <0.05). The bone density and volume of regenerated bone in the rhBMP‐2 group were greater than in the control group after 6 weeks of consolidation (P <0.001). Conclusion: Injection of rhBMP‐2 into regenerated bone after a distraction osteogenesis procedure significantly increased bone volume in the dentoalveolar distraction site and improved both the width and height of the alveolar ridge and increased the bone density.     

渗透树脂治疗对釉质白斑样病损颜色的影响

目的 研究渗透树脂治疗对釉质白斑样病损颜色的影响。方法 选择人磨牙60颗,树脂包埋,以牙尖方向作为观察面,每个样本打磨出2个釉质小平面,随机分为A、B点。60颗样本牙随机分为第1、2、3组,每组20颗,经人工龋脱矿液分别脱矿24、48、72 h;对各样本的A点进行渗透树脂处理,B点行0.1%氟化钠涂氟处理30 d,B点涂氟处理后再行渗透树脂处理。应用电子分光光度比色仪测量A、B点脱矿及处理前后的L*值。结果 各组A、B点脱矿前L*值没有明显差异,脱矿后均明显增加;经渗透树脂处理后,各组A点的L*值均较脱矿后降低,第1、2组的L*值恢复到脱矿前水平,第3组L*值与第1、2组存在差异（P<0.05）;经涂氟处理后,各组B点的L*值变化不明显;涂氟再经渗透树脂处理后,B点L*值明显降低,但仍高于A点和脱矿前（P<0.05）。结论 渗透树脂能够有效改善釉质白斑样病损的颜色,即刻效果优于传统涂氟治疗;其治疗效果与釉质脱矿程度及龋损活动性有关。     

Tissue reactions to subperiosteal onlays of demineralized xenogenous dentin blocks in rats

Abstract – Objectives:  This study was undertaken to examine the influence of partial demineralization of xenogenous dentin on bone formation in an osteoconductive environment. Materials and methods:  Sixty dentin blocks, 2–3 mm thick and 4 mm in diameter, were prepared from developing teeth of young pigs. Forty blocks were demineralized in 24% ethylenediaminetetraacetic acid (pH 7.0) for 1, 2, 6 or 12 h. Forty adult rats divided into eight groups with five rats in each group were used. A sagittal midcranial incision was made from the occipital to the frontal region. Through a subperiostal dissection, a pocket was created on each side of the skull. One demineralized block was placed on one side, and a non‐demineralized block was placed on the contralateral side, or the pocket was left empty as controls. Thus, eight experimental groups with five rats in each were formed. Results:  Resorption increased significantly with increasing degree of demineralization while bone formation increased significantly with increasing degree of demineralization, provided inflammation was compensated for. This suggests an important role for inflammation or infection control during the healing period of osteogenic implants to optimize osseous integration in an osteoconductive environment. Conclusion:  Partial demineralization of xenogenous dentin blocks may provide a method for optimizing the integration of dentin onlays in an osteoconductive environment, thus stabilizing the implant and slowing down replacement resorption.     

Clinical and Immunoinflammatory Evaluation of One‐Stage Full‐Mouth Ultrasonic Debridement as a Therapeutic Approach for Smokers With Generalized Aggressive Periodontitis: A Short‐Term Follow‐Up Study

Background: This study aims to evaluate the effect of one‐stage full‐mouth ultrasonic debridement (OSFMUD) on clinical and immunoinflammatory parameters in smokers with generalized aggressive periodontitis (GAgP). Methods: Fourteen smoking and 14 non‐smoking patients with GAgP were selected. After initial supragingival therapy, patients were treated by OSFMUD. Full‐mouth parameters evaluated were: 1) plaque index (PI); 2) bleeding scores (BS); 3) probing depth (PD); and 4) clinical attachment level (CAL). Clinical evaluation was performed, and gingival crevicular fluid (GCF) was collected for selected sites (ss) at baseline and 1, 3, and 6 months. GCF was analyzed via enzyme‐linked immunosorbent assay for: 1) receptor activator of nuclear factor‐κ B ligand (RANKL); 2) osteoprotegerin (OPG); 3) interleukin (IL)‐6; and 4) tumor necrosis factor (TNF)‐α, whereas secreted osteoclastogenic factor of activated T‐cells (SOFAT) was evaluated by Western blotting. Results: Significant reduction (P <0.05) was observed between baseline and 6 months for: 1) PI; 2) BS; and 3) PD, with no difference between smoking and non‐smoking patients (P >0.05). Regarding CAL, only non‐smoking patients showed a significant decrease (P <0.05). Significant reduction (P <0.05) was observed in both groups for: 1) PIss; 2) PDss; 3) bleeding on probing; and 4) relative CAL. Smoking and non‐smoking patients presented significantly decreased levels of IL‐6 and TNF‐α over time (P <0.05); however, no difference was observed between groups (P >0.05). RANKL was significantly different (P <0.05) only for non‐smokers at 6 months, whereas OPG was not significant (P >0.05). SOFAT expression was significantly lower (P <0.05) after OSFMUD for non‐smokers only. Conclusion: Considering the clinical and immunoinflammatory parameters evaluated in this short‐term follow‐up study, it can be concluded that OSFMUD can be used as an alternative treatment for smokers with GAgP.     

Collaborative Cross Mouse Population for Studying Alveolar Bone Changes and Impaired Glucose Tolerance Comorbidity After High‐Fat Diet Consumption

Background: High‐fat diet (HFD), body weight (BW) gain, and impaired glucose tolerance development are associated with alveolar bone loss (ABL) in susceptible individuals. This report explores the Collaborative Cross (CC) mouse population for studying the impact of genetic background on comorbidity of alveolar bone change and glucose tolerance after HFD consumption. Methods: Seventy‐eight mice from 19 different CC lines were maintained on rodent chow diet for 8 weeks and were subsequently transferred to an HFD (42% fat) for an additional 12 weeks. BW changes were assessed, and glucose tolerance was measured using an intraperitoneal glucose tolerance test (IPGTT). Six cytokines/chemokines were quantified by multiplex immunoassay, alveolar bone volume was quantified by microcomputed tomography, and the ABL phenotype was calculated relative to a control group (143 mice maintained on standard chow diet for 20 weeks). Results: The glucose tolerance response after HFD significantly varied among CC lines (P <0.01), with a significant effect of sex (P <0.01). Alveolar bone changes significantly varied among CC lines (P <0.01). Overall, there was no significant correlation between alveolar bone volume changes and increased BW or glucose tolerance response. However, individual CC lines were identified that showed type 2 diabetes mellitus (t2DM) development and significant alveolar bone volume change (P <0.05), whereas others showed t2DM development, regardless of periodontitis. Interleukin‐6 significantly correlated with alveolar bone changes (P <0.05), whereas adipsin showed a negative correlation with IPGTT area under the curve values (P <0.05). Conclusion: The present results demonstrate the power of CC mice for studying the genetic background impact between comorbidity of t2DM and bone loss.     

Therapeutic Effects of Melatonin on Alveolar Bone Resorption After Experimental Periodontitis in Rats: A Biochemical and Immunohistochemical Study

Background: The present study aims to investigate the effects of systemic melatonin administration on alveolar bone resorption in experimental periodontitis in rats. Methods: Twenty‐four male Sprague‐Dawley rats were divided into three groups (control, experimental periodontitis [Ped], and experimental periodontitis treated with melatonin [Mel‐Ped]). For periodontitis induction, first molars were ligatured submarginally for 4 weeks. After ligature removal, rats in the Mel‐Ped group were treated with a daily single dose of 10 mg/kg body weight melatonin for 15 consecutive days. At the end of the study, intracardiac blood samples and mandible tissues were obtained for histologic, biochemical, and radiographic analysis. Serum markers related to bone turnover, calcium, phosphorus, bone alkaline phosphatase (b‐ALP), and terminal C telopeptide of collagen Type I (CTX) were analyzed. Myeloperoxidase levels were determined in gingival tissue homogenates, and receptor activator of nuclear factor‐kappa B ligand (RANKL) activation was analyzed in the mandible samples stereologically. Alveolar bone loss was also evaluated radiographically in the mandible samples of each group. Results: Melatonin treatment decreased serum CTX levels and increased b‐ALP levels. Serum calcium and phosphorus levels were not statistically different among groups (P >0.05). Alveolar bone resorption and myeloperoxidase activity were statistically higher in the Ped group compared to the Mel‐Ped group (P <0.05). Immunohistochemical staining of RANKL and osteoclast activity were significantly lower in the Mel‐Ped group compared to the Ped group (P <0.05). Conclusion: This study reveals that melatonin treatment significantly inhibits regional alveolar bone resorption and contributes to periodontal healing in an experimental periodontitis rat model.     

Demineralization of the Contacting Surfaces in Autologous Onlay Bone Grafts Improves Bone Formation and Bone Consolidation

Background: Autologous bone grafts are usually well consolidated after 4 to 5 months but can be incompletely interlocked with the native bone. This study investigated the effect of acid demineralization of the graft–bed interface on graft consolidation. Methods: Onlay bone grafts were performed on the calvaria of 36 guinea pigs. Half of the animals had the graft–bed contacting surfaces demineralized with 50% citric acid (pH 1.0) for 3 minutes (test group). The other half received no demineralization (control group). The bone grafts were immobilized by a resorbable membrane glued to the recipient bed with cyanoacrylate. After 7, 30, and 90 days, specimens (n = 6) were obtained for light microscopy. Data from qualitative analysis and computerized histomorphometry were statistically processed at a significance level of 5%. Results: Osteogenesis was not seen at the interface after 7 days. After 30 days, the test group showed 34.39% ± 13.4% of the interface area filled with mineralized tissue, compared to 17.14% ± 8.6% in the control group (P = 0.026). After 90 days, the mean percentages of mineralized tissue at the interface in the test and control specimens were 54.00% ± 11.23% and 38.65% ± 7.76% (P = 0.041), respectively. Within groups, a higher percentage of the area filled with mineralized tissue was seen at 90 days compared to 30 days (P = 0.004 for control and 0.041 for test). Conclusions: Demineralization of the contacting surfaces between autologous bone graft and bone bed improved new bone formation and bone consolidation. These data need to be confirmed in humans.     

Smoking and matrix metalloproteinases,neutrophil elastase and myeloperoxidase in chronic periodontitis

Oral Diseases (2010) 17 , 68–76 Objectives: To investigate possible relationship between smoking and serum concentrations of matrix metalloproteinase‐8,‐9 (MMP‐8, MMP‐9), tissue inhibitor of matrix metalloproteinases‐1 (TIMP‐1), neutrophil elastase (NE), myeloperoxidase (MPO) in chronic periodontitis (CP) patients relative to periodontally healthy subjects. Methods: Serum samples were obtained from 111 subjects before initiation of any periodontal intervention. Fifty‐five CP patients (39 non‐smokers, 16 smokers) and 56 periodontally healthy subjects (39 non‐smokers, 17 smokers) were recruited. Serum concentrations of MMP‐8 were determined by IFMA and MPO, MMP‐9, TIMP‐1, NE concentrations by ELISA. ANCOVA and Pearson correlation analysis was utilized for statistical analysis. Results: Serum MPO, NE concentrations were higher in smoker CP than non‐smoker CP patients (P = 0.002 and P < 0.001, respectively), whereas these were similar in smoker, non‐smoker periodontally healthy groups (P > 0.05). TIMP‐1 concentration was higher in non‐smoker CP than smoker CP group (P < 0.05). MMP‐9/TIMP‐1 ratios were higher in smoker CP than non‐smoker CP group (P = 0.01). MMP‐8 concentrations, MMP‐8/TIMP‐1 and MMP‐9/TIMP‐1 ratios in CP group were not significantly different from those in periodontally healthy group (P > 0.05). Conclusions: Our findings of significantly elevated serum MMP‐9, MPO, NE together with decreased TIMP‐1 in smoker CP patients than non‐smokers support that smoking together with periodontal destruction may expose/predispose to cardiovascular diseases.     

Comparison of Glycated Hemoglobin Levels in Individuals Without Diabetes and With and Without Periodontitis Before and After Non‐Surgical Periodontal Therapy

Background: Only a few studies have examined the association between periodontitis and glycated hemoglobin (HbA1c) levels in individuals without diabetes. The aim of this study is to compare HbA1c levels in individuals without diabetes and with and without periodontitis before and after non‐surgical periodontal therapy. Methods: This comparative study was done on individuals without diabetes who were 35 to 65 years old. Group A consisted of 30 individuals without periodontitis, and group B consisted of 30 individuals with periodontitis. Body mass indices and clinical parameters, including oral hygiene index‐simplified (OHI‐S) score, gingival index (GI), probing depth (PD), clinical attachment level (CAL), and HbA1c level, of all participants were recorded. All participants received non‐surgical periodontal therapy (scaling and root planing). After 3 months, all participants were reexamined, and clinical parameters and HbA1c levels were evaluated and compared to baseline values. Results: There were significant differences between group A and group B in regard to baseline OHI‐S, GI, PD, and HbA1c (P <0.05). There was no clinical attachment loss in group A, either at baseline or after 3 months. At the end of 3 months, group B showed improvement in all clinical parameters (P <0.05) and their HbA1c levels also significantly decreased (P <0.05), although the values never reached those of group A. Conclusion: The HbA1c levels of individuals without diabetes and with periodontitis (group B) were significantly reduced 3 months after non‐surgical periodontal therapy, although they never reached the same levels as those of the individuals without diabetes or periodontitis (group A).     

Opposing Effects of Diabetes and Tetracycline on the Degradation of Collagen Membranes in Rats

Background: Increased collagenolytic activity, characteristic of uncontrolled diabetes, may compromise collagen membrane (CM) survival. Tetracycline (TCN) possesses anticollagenolytic properties and delays CM degradation in healthy animals. This study evaluates the degradation of TCN‐‐immersed and ‐non‐immersed CMs in rats with diabetes compared to those with normoglycemia. Methods: Diabetes was induced in 15 12‐week‐old male Wistar rats by injection of 65 mg/kg streptozotocin. The control group consisted of 15 rats with normoglycemia. Sixty bilayered CM disks were labeled before implantation with aminohexanoyl‐biotin‐N‐hydroxy‐succinimide ester, of which 30 were immersed in 50 mg/mL TCN solution (experimental) or phosphate‐buffered saline (PBS) (control). In each animal, two disks (control and experimental) were implanted in two midsagittal calvarial defects in the parietal bone. Similar non‐implanted disks served as baseline. After 3 weeks, animals were euthanized, and the calvaria and overlying soft tissues were processed for demineralized histologic analysis. Horseradish peroxidase‐conjugated streptavidin was used to detect the biotinylated collagen. The area of residual collagen within the membrane disks was measured and analyzed with a digital image analysis system. Several slides from each specimen were also stained with hematoxylin and eosin. Statistical analysis consisted of paired and unpaired t tests. Results: The amount of residual collagen in PBS‐immersed disks was lower in rats with diabetes compared to rats with normoglycemia (69% of baseline versus 93%, respectively, P <0.001). TCN immersion increased the amount of residual collagen contents in both diabetic (83% of baseline) and healthy (97.5% of baseline) animals (P <0.0001). Conclusion: Diabetes increases CM degradation, whereas immersion in 50 mg/mL TCN solution before implantation presents an opposite effect.     

Effects of Probiotic Therapy on Metabolic and Inflammatory Parameters of Rats With Ligature‐Induced Periodontitis Associated With Restraint Stress

Background: This study evaluates the effects of probiotic therapy (PT) in rats with ligature‐induced periodontitis associated with restraint stress. Methods: Sixty‐four rats were divided into control, stress (STR), probiotic (PROB), periodontal disease (PD), STR‐PROB, STR‐PD, STR‐PROB‐PD, and PROB‐PD groups. The probiotic was added to the drinking water for 44 days. PD was induced by a ligature. In STR groups, the animals were subjected to restraint stress for 2.5 hours per day for 30 days. Results: Rats with PD exhibited increased alveolar bone loss (P <0.05), as well as increased levels of cyclooxygenase‐2, serum C‐terminal telopeptide (CTX), p38 mitogen‐activated protein kinase (p38), and receptor activator of nuclear factor‐κB ligand and decreased levels of osteoprotegerin (OPG). Stressed rats presented high levels of C‐peptide, corticosterone, and glucose (P <0.05). In general, the presence of stress reduced the expression of CTX and p38 (P <0.05). PT reduced alveolar bone loss in unstressed animals. It also decreased expression of CTX and induced increased expression of OPG in unstressed animals with PD. However, PT was not effective in preventing bone loss or altering the expression of inflammatory markers in stressed animals. PT decreased the number of inflammatory cells in the periodontal tissue (P <0.05). Groups with stress and PD showed decreased villous height and crypt depth. Stress seemed to prevent part of the probiotic beneficial effects on the small intestine. Conclusions: Based on the methodology used, PT may reduce tissue breakdown resulting from PD in unstressed rats. The protocol used for restraint stress influenced the immunomodulatory effects of PT in intestinal and periodontal tissues.     

Can demineralized enamel surfaces be bonded safely?

Objective. To evaluate and compare the effects of enamel demineralization, microabrasion therapy and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application on the shear bond strength (SBS) of orthodontic brackets bonded to enamel surfaces and enamel color. Materials and methods. Eighty freshly extracted human maxillary premolar teeth were allocated to one of the four groups. Brackets were bonded directly to non-demineralized enamel surfaces in Group I (control group), directly to the demineralized enamel surfaces in Group II, to demineralized enamel surfaces after CPP-ACP application in Group III and to demineralized enamel surfaces after microabrasion therapy in Group IV. The samples were stored in water for 24 h at 37°C and then underwent thermocycling. The SBS in megapascals (MPa) was determined by a shear test with 0.5 mm/min crosshead speed and failure types were classified with modified adhesive remnant index scores. The data were analyzed with one-way analyses of variance (ANOVA), Tukey and chi-square tests at the α = 0.05 level. Results. Significant differences were found among the four groups (F = 21.57, p < 0.01). No significant difference was found between Group I and III (17.12 ± 2.84 and 15.08 ± 3.42 MPa, respectively) or between Group III and IV (12.82 ± 2.64 MPa). The lowest SBS value was determined in Group II (5.88 ± 2.12 MPa). Enamel demineralization, microabrasion therapy and CPP-ACP application affected enamel color significantly. Conclusion. CPP-ACP application and microabrasion therapy are able to increase the decreased SBS of orthodontic brackets because of enamel demineralization.     

Influence of the Utilization Time of Different Manual Toothbrushes on Oral Hygiene Assessed During a 6‐Month Observation Period: A Randomized Clinical Trial

Background: The aim of this randomized clinical trial (RCT) was to investigate whether 6‐month continuous use of different manual toothbrushes (TBs) influences plaque removal and the degree of gingival inflammation compared to short utilization periods of 4 weeks each. Methods: In total, 96 participants were randomly allocated into two groups: continuous use during 6 months (non‐renewal group) or a change in TB every 4 weeks during 6 months (renewal group). Each group was subdivided into four subgroups (groups A to H; n = 12 each) according to the head size (normal or short) and bristle hardness (medium or soft) of the TB used. The modified Quigley–Hein plaque index (QHI), papilla bleeding index (PBI), and gingival index (GI) were recorded at baseline and 2, 8, 12, 16, and 24 weeks after baseline. After 24 weeks, each participant received a new TB, and at week 26, the final QHI, PBI, and GI were determined. The statistical evaluation consisted of analysis of covariance (P <0.05). Results: With time, QHI, PBI, and GI were significantly different between the renewal and the non‐renewal groups (QHI: P = 0.02; PBI: P = 0.04; GI: P <0.01), independent of subgroup. In the renewal group, QHI showed a significant decrease between baseline and each follow‐up visit (P <0.01). In the non‐renewal group, there was a significant decrease compared to baseline up to and including week 16 (P <0.01). PBI in the renewal group showed no significant differences between baseline and each follow‐up visit (P >0.05). In the non‐renewal group, only the normal head/soft subgroup exhibited a significant increase at week 24 (P = 0.02). The GI in the renewal group showed no difference between baseline and all follow‐up visits, whereas in the non‐renewal group, there was a significant decrease up to and including week 12 (P <0.05). Conclusions: Six‐month continuous use reduced the effectiveness of the TB with respect to plaque removal, and gingival inflammation appeared to increase.