Resistance of Mandibular Polyurethane Replicas to Fracture After Removal of Blocks From the Symphysis and Ramus.

BACKGROUND: When block grafts are harvested intraorally, the donor sites may act as stress concentrators and alter the structural integrity of the mandible. PURPOSE: The study aimed to compare displacement and load failure between intact polyurethane mandibular replicas and similar replicas from which blocks were taken at the symphysis or the ramus. It also aimed to identify trends of load failure. MATERIALS AND METHODS: Thirty-five mandibular replicas were tested to failure with an electromagnetic material testing unit. The variables evaluated in this investigation were maximal load, displacement at maximal load, and fracture location. RESULTS: Statistically significant differences in maximal load were detected between groups (P = 0.0008). Differences between fracture locations were also statistically significant (P < 0.0001). The mandibles from which blocks were removed at the symphysis were significantly more likely to break at a lower maximal load than were the control mandibles (P = 0.0010) or the mandibles from which blocks were removed at the ramus (P = 0.0162). They were also more likely than the control group to break at a lower displacement at maximal load (P = 0.0145). CONCLUSIONS: Location of the donor site significantly influences the structural integrity of mandibular replicas. In addition, the donor site significantly affects the location of mandibular fractures.

Osteoporosis and bisphosphonate-related osteonecrosis in a dental school implant patient population.

PURPOSE: Studies have demonstrated an inconsistent association between implant failure and bone mineral density. The prevalence of osteoporosis in US adults has been reported to range from 5% to 10% in women and from 2% to 4% in men. The prevalence of bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) has been reported to range from 0% to 4.3% of patients taking oral BPs. The purpose of this study was to calculate the risk of dental implant loss and the incidence of BRONJ in patients with osteoporosis at the University of Kentucky College of Dentistry (UKCD). MATERIALS AND METHODS: This study analyzed data collected from patients who had implants placed between 2000 and 2004 at UKCD. Data were gathered from patient interviews regarding implant survival and patient-satisfaction parameters, and interviews were conducted either chairside at a scheduled maintenance appointment or by telephone interview. RESULTS: Among 203 patients who received 515 implants, the prevalence of osteoporosis was 23.3% for women and 1.2% for men. None of the 20 patients who reported a history of oral BP use exhibited BRONJ, and there were no implant failures in patients with a history of osteoporosis. CONCLUSIONS: In this study, osteoporosis conferred no risk of implant failure, and oral BP therapy was not associated with BRONJ.

Patterns of salivary analytes provide diagnostic capacity for distinguishing chronic adult periodontitis from health.

Salivary biomarker discovery requires identification of analytes with high discriminatory capacity to distinguish disease from health, including day-to-day variations that occur in analyte levels. In this study, seven biomarkers associated with inflammatory and tissue destructive processes of periodontal disease were investigated. In a prospective cohort study design, analyte expression levels were determined in unstimulated whole saliva samples collected on multiple occasions from 30 healthy adults (i.e., orally and systemically) and 50 chronic adult periodontitis patients. Salivary levels of IL-1ß, IL-6, MMP-8, and albumin were significantly elevated (5.4 to 12.6X) and levels of IFNα were consistently lower (8.7X) in periodontitis patients compared with the daily variation observed in healthy adults. ROC analyses of IL-1ß, IL-6 and MMP-8 yielded areas under the curves of 0.963-0.984 for discriminating periodontitis from health. These results demonstrate that levels of salivary bioanalytes of patients who have periodontitis are uniquely different from normal levels found in healthy subjects, and a panel consisting of IL-1ß, MMP-8 and IL-6 shows particular diagnostic potential.

Povidone-iodine may provide small adjunctive benefit to scaling and root planing.

STUDY SELECTION CRITERIA: An electronic search was performed using a priori selection criteria. PubMed, EMBASE, and the Cochrane Central Library were searched. Studies were limited to randomized, controlled trials in which povidone-iodine (PVP-I) was used as an adjunct to conventional SRP in the treatment of chronic periodontitis. KEY STUDY FACTOR: The authors reviewed evidence supporting the use of PVP-I as an intrasulcular irrigant during SRP in the treatment of chronic periodontitis. MAIN OUTCOME MEASURE: Reduction in probing depth was the primary outcome measure. MAIN RESULTS: One hundred eighty-six titles resulted from the search. Thirty-two full-text articles were assessed. Twenty-five articles were excluded. The remaining 7 articles were assessed by 2 independent reviewers. One of these studies could not be included in the meta-analysis because of incomplete data reporting. The use of PVP-I resulted in statistically significant additional pocket depth reduction over that achieved by the standard therapy (scaling and root planing). The magnitude of this difference was 0.28 mm (95% CI: 0.08-0.48). This benefit was sustained at 3 months posttreatment (0.23 mm; 95% CI: -0.03 to 0.48). CONCLUSIONS: The use of PVP-I as an adjunct to SRP resulted in a small additional benefit beyond that achieved with SRP alone.

Novel calcium sulfate space-making devices for bone regeneration: a pilot study.

The feasibility of using preformed calcium sulfate (CS) space-making devices (SMDs) for bone regeneration was explored using a rabbit calvarial model. Twenty-four CS devices were fabricated. Twelve of these were SMDs, which consisted of a domed head that served as the actual space-maker, and a stalk or "tail" portion used to affix the device to the bone. A second set of control devices (CDs) was fabricated that consisted of only the tail portion. CDs were made of medical-grade CS, as were 9 of the SMDs. Six of the CS SMDs were loaded with high or low concentrations of simvastatin. The remaining 3 SMDs were made of a CS/bioactive glass composite. One SMD and 1 CD were implanted bilaterally in the parietal bones of 12 New Zealand White rabbits, which were euthanized 8 weeks following surgery. All implants were well tolerated. In all animals, the side receiving the SMD exhibited greater thickness than did the control sites. The addition of simvastatin resulted in a statistically significant difference in calvarial thickness. The CS/bioactive glass composite also yielded encouraging results. The CS resorbable SMDs are worthy of further investigation.

Programmatic effectiveness of a university-based implant training program: long-term, patient-centered outcomes.

The University of Kentucky College of Dentistry established a formal implant program in 1999. The program utilizes a single system (Straumann) and a team concept in which implants are placed by residents in period ontology or oral and maxillofacial surgery and restored by predoctoral dental students. The program features stringent patient inclusion and exclusion criteria, incremental structured learning experiences, formal standardized protocols, and hands-on preclinical learning experiences. The use of a single system simplified training protocols and inventory requirements. Complete and partially edentulous patients requiring single and multiple implants are eligible for the program, although maxillary anterior sites are excluded. There is a formal quality assurance program to assess patient-centered outcomes. The current report includes data for patients who had implants placed in the period from January 2000 through December 2002. During that period, 192 patients received dental implants, of which 116 patients (248 implants) were available for analysis. The mean follow-up was 7.05 years (median = 7.32 years). The implant survival rate was 98.4%, while the success rate was 93.15%. Success was determined by the absence of pain or mobility, as well as self-reported patient satisfaction with function, appearance, and surgical experience.

Povidone-iodine may provide small adjunctive benefit to scaling and root planing.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Systematic review on the effect of rinsing with povidone-iodine during nonsurgical therapy. Sahrmann P, Puhan MA, Attin T, Scmidlin PR. J Periodontal Res 2010;45:153-64. REVIEWER: Mark V. Thomas, DMD. PURPOSE/QUESTION: In patients with chronic periodontitis, does intrasulcular irrigation with povidone-iodine (PVP-I) offer an adjunctive benefit over conventional scaling and root planing (SRP)? SOURCE OF FUNDING: None disclosed. TYPE OF STUDY DESIGN: Systematic review with meta-analysis LEVEL OF EVIDENCE: Level 3: Other evidence. STRENGTH OF RECOMMENDATION GRADE: Grade C: Consensus, disease-oriented evidence, expert opinion.

Within-subject variability in repeated measures of salivary analytes in healthy adults.

BACKGROUND: Saliva contains a large number of biomolecules, some of which have putative diagnostic usefulness. A potential problem with the use of biomolecules in diagnosis is day-to-day fluctuation due to within-subject variability. This study evaluated the intraindividual variability of six salivary analytes in healthy adults and determined their normal range. METHODS: Unstimulated whole saliva (5 ml) was collected every 2 to 3 days on six occasions from 30 subjects in good oral and systemic health. Four of the samples were collected in the clinic, and two were collected by the subject at home. The concentration ranges of interleukin (IL)-1beta, IL-6, matrix metalloproteinase-8, prostaglandin E(2), tumor necrosis factor-alpha, interferon-alpha, and albumin were examined. Descriptive statistics were computed, and a one-way random-effects model was used to quantify within- and between-subject components of variability. Intraclass correlation coefficients (ICCs) were calculated for each subject/analyte combination. RESULTS: Within-subject coefficients of variation for these analytes ranged from 67.6% to 172.1% for the in-clinic samples and from 111.9% to 201.0% for the at-home samples. The ICC for the various analytes ranged from 41% to 61% for the in-clinic samples. The at-home samples exhibited significantly more variability than did those obtained in the clinic under supervision. CONCLUSIONS: There was marked within-subject variation in the salivary concentrations of these analytes. With increased interest in salivary diagnostics, the within-subject variability, normal range, and threshold levels for abnormal levels of individual salivary analytes need to be determined if these diagnostics tests are to have clinical usefulness.

Localized intermittent delivery of simvastatin hydroxyacid stimulates bone formation in rats.

BACKGROUND: The cholesterol-lowering drug simvastatin promotes bone formation in cell cultures and animal models. In previous studies, devices for the controlled, localized delivery of simvastatin hydroxyacid enhanced osteoblastic activity in vitro. The objective of this investigation was to determine bioactivity of the delivery system in vivo. METHODS: Devices for sustained or intermittent release of simvastatin hydroxyacid were formed using a blend of cellulose acetate phthalate and a poly(ethylene oxide) and poly(propylene oxide) block copolymer, and they were implanted directly over the calvarium of young male rats. Drug-free devices were used as controls. After 9, 18, or 28 days, specimens were histologically evaluated for new bone formation. RESULTS: All three groups showed some level of new bone formation, but the extent of osteogenesis depended on the type of implant. Devices delivering simvastatin hydroxyacid were associated with a 77.5% to 133% increase in new woven bone thickness compared to control devices without a drug (P<0.05). Furthermore, intermittent release stimulated a 32.3% greater response in bone thickness and a 74.1% greater bone area than did sustained delivery (P<0.05). Although a minimal thickness of woven bone was formed directly under the device (up to 36 microm), a significantly thicker layer was observed at the periphery (up to 205 microm), implying mechanical and/or chemical effects directly under the implant. The percentage of lamellar bone area for intermittent and sustained release was higher than that for the control group (P<0.05). CONCLUSION: Based on the present results of enhanced bone formation, these devices for the intermittent delivery of simvastatin hydroxyacid merit further attention for localized osteogenesis.

Bone remodeling biomarkers of periodontal disease in saliva.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha), C-telopeptide pyridinoline cross-links of type I collagen (ICTP), and receptor activator of nuclear factor-kappa B ligand (RANKL) have been associated with bone remodeling and periodontal tissue destruction. This study evaluated the level of these biomarkers in saliva with respect to periodontal disease status. METHODS: Levels of TNF-alpha in unstimulated whole saliva of 74 adults (35 subjects with moderate to severe periodontal disease and 39 healthy controls) and salivary levels of RANKL and ICTP of a subset of 21 subjects and 21 matched controls were examined using enzyme immunosorbent assays in a case-control clinical study. RESULTS: Salivary levels of TNF-alpha were detected in all subjects, whereas levels of ICTP and RANKL were detected in only a minority of subjects. Mean salivary levels of TNF-alpha were significantly higher in individuals with periodontal disease (mean: 4.33 pg/ml) than in controls (mean: 2.03 pg/ml; P = 0.02), with a maximum level (27.96 pg/ml) observed in periodontitis. Subjects with salivary TNF-alpha levels above a threshold of 5.75 pg/ml (i.e., two standard deviations above the mean of the controls) had significantly more sites with bleeding on probing, probing depths >/=4 mm, and attachment loss > or =2 mm (P < or =0.01). CONCLUSION: Salivary levels of TNF-alpha were elevated in patients who had clinical indicators of periodontitis, suggesting that this biomarker may serve in a panel of salivary biomarkers that could facilitate the screening, diagnosis, and management of periodontal disease.

Infection control in the dental office.

The risk of infectious disease transmission is an inherent part of dental practice. Fortunately, such risks can be greatly reduced through modern infection control practices. Such practices include the use of various measures, including administrative, engineering, and work practice controls. Such measures should be codified in an office infection control plan, which should form the basis for the daily infection control activities of the staff. This article discusses some of the measures that should be taken to safeguard the health of dental healthcare workers and patients.

Regulatory compliance in the dental office.

Dentists in the private sector, as well as their academic counterparts, must comply with a variety of federal, state, and local regulations. The scope of this regulation ranges from specifying who may engage in the practice of dentistry to the disposition of extracted teeth. In this review, some requirements imposed by various regulatory agencies are described. Because of the importance of state and local oversight, each clinician must determine what state and local requirements exist for them. A number of states have enacted various regulations that are more stringent than the federal versions. It is necessary, therefore, to seek appropriate local counsel regarding applicable statutes and regulations.

Lab-on-a-chip methods for point-of-care measurements of salivary biomarkers of periodontitis.

Salivary secretions contain a variety of molecules that reflect important pathophysiological activities. Quantitative changes of specific salivary biomarkers could have significance in the diagnosis and management of both oral and systemic diseases. Modern point-of-care technologies with enhanced detection capabilities are needed to implement a significant advancement in salivary diagnostics. One such promising technology is the recently described lab-on-a-chip (LOC) assay system, in which assays are performed on chemically sensitized beads populated into etched silicon wafers with embedded fluid handling and optical detection capabilities. Using this LOC system, complex assays can be performed with small sample volumes, short analysis times, and markedly reduced reagent costs. This report describes the use of LOC methodologies to assess the levels of interleukin-1beta (IL-1beta), C-reactive protein (CRP), and matrix metalloproteinase-8 (MMP-8) in whole saliva, and the potential use of these biomarkers for diagnosing and categorizing the severity and extent of periodontitis. This study demonstrates that the results achieved by the LOC approach are in agreement with those acquired with standard enzyme-linked immunosorbent assay (ELISA), with significant IL-1beta and MMP-8 elevations in whole saliva of periodontitis patients. Furthermore, because of the superior detection capacities associated with the LOC approach, unlike those with ELISA, significant differences in CRP levels between periodontitis patients and normal subjects are observed. Finally, principal component analysis (PCA) is performed to yield an efficient method to discriminate between periodontally healthy and unhealthy patients, thus increasing the diagnostic value of these biomarkers for periodontitis when examined with the integrated LOC sensor system.

Bioerodible devices for intermittent release of simvastatin acid.

The association polymer system of cellulose acetate phthalate (CAP) and Pluronic F-127 (PF-127) was used to create intermittent release devices for mimicking the daily injection of simvastatin that has been reported to stimulate bone formation. To enhance solubility in water, prodrug simvastatin was modified by lactone ring opening, which converts the molecule to its hydroxyacid form. CAP/PF-127 microspheres incorporating simvastatin acid were prepared by a water-acetone-oil-water (W/A/O/W) triple emulsion process. Devices were then fabricated by pressure-sintering UV-treated blank and drug-loaded microspheres. Using a multilayered fabrication approach, pulsatile release profiles were obtained. Delivery was varied by changing loading, number of layers, blend ratio, and incubation conditions. To determine the cellular effects of intermittent exposure to simvastatin acid, MC3T3-E1 cells were cultured with either alternating or sustained concentrations of simvastatin acid in the medium, and DNA content, alkaline phosphatase activity, and osteocalcin secretion were measured. For all three cell responses, cultures exposed to simvastatin acid showed higher activity than did control cultures. Furthermore, cell activity was greater for cells cultured with intermittent concentrations of simvastatin acid compared to cells that were constantly treated. These results imply that devices intermittently releasing simvastatin acid warrant further study for locally promoting osteogenesis.

Salivary biomarkers of existing periodontal disease: a cross-sectional study.

BACKGROUND: The authors conducted a study to determine if salivary biomarkers specific for three aspects of periodontitis--inflammation, collagen degradation and bone turnover--correlate with clinica features of periodontal disease. METHODS: The relationship between periodontal disease and the levels of interleukin-1 beta (IL-1beta), matrix metalloproteinase (MMP)-8, and osteoprotegerin (OPG) in whole saliva of 57 adults (28 "case" subjects with moderate-to-severe periodontal disease and 29 healthy control subjects) was examined in a case-control trial. RESULTS: Mean levels of IL-1beta and MMP-8 in saliva were significantly higher in case subjects than in controls. Both analytes correlated with periodontal indexes, whereas, after adjustment for confounders, OPG did not. Elevated salivary levels of MMP-8 or IL-1beta (more than two standard deviations above the mean of the controls) significantly increased the risk of periodontal disease (odds ratios in the 11.3-15.4 range). Combined elevated salivary levels of MMP-8 and IL-1beta increased the risk of experiencing periodontal disease 45-fold, and elevations in all three biomarkers correlated with individual clinical parameters indicative of periodontal disease. CONCLUSION: Salivary levels of MMP-8 and IL-1beta appear to serve as biomarkers of periodontitis. CLINICAL IMPLICATIONS: Qualitative changes in the composition of salivary biomarkers could have significance in the diagnosis and treatment of periodontal disease.

Implant surfaces.

Available in many shapes, sizes, and lengths, dental implants are also crafted from different materials with different surface proper-ties. Among the most desired characteristics of an implant are those that ensure that the tissue-implant interface will be established quickly and then will be firmly maintained. Because many variables affect oral implants, it is sometimes difficult to reliably predict the likelihood of an implant's success. It is especially difficult to assess whether the various modifications in the latest implants deliver improved performance. This article focuses primarily on important surface characteristics and their potential effects on the performance of dental implants.

Evidence-based decision-making: implants versus natural teeth.

The clinician is increasingly confronted with the dilemma of whether to use implants or so-called "traditional" dental interventions. Given the high predictability of implants, their use should be considered routine. The survival and success rates reported by many investigators often exceed the success rates of some forms of heroic treatment. Findings from well-designed trials must be used to guide clinical decision-making. In this article, the authors review studies of outcomes related to one particular implant system and compare these results to those reported for various forms of endodontic therapy and tissue-supported mandibular complete dentures. The results suggest that implant restorations of the system in question have a level of predictability equal to or greater than that for traditional dental treatment.

Implant anchorage in orthodontic practice: the Straumann Orthosystem.

Dental implants have been used to provide orthodontic anchorage. This article provides an overview of the Straumann Orthosystem implant system (Institut Straumann, Waldenburg, Switzerland) and its application, including the anatomy of the bony palate and contiguous structures. Considerations in placement of the Orthosystem implant include the avoidance of contiguous anatomic structures such as the nasal cavity, the degree of ossification of the palatal suture, and the quality and quantity of bone in the proposed implant site, all of which are discussed in this article.

Comparison of sequential drug release in vitro and in vivo.

Development of drug-delivery devices typically involves characterizing in vitro release performance with the inherent assumption that this will closely approximate in vivo performance. Yet, as delivery devices become more complex, for instance with a sequential drug release pattern, it is important to confirm that in vivo properties correlate with the expected "programming" achieved in vitro. In this work, a systematic comparison between in vitro and in vivo biomaterial erosion and sequential release was performed for a multilayered association polymer system comprising cellulose acetate phthalate and Pluronic F-127. After assessing the materials during incubation in phosphate-buffered saline, devices were implanted supracalvarially in rats. Devices with two different doses and with different erosion rates were harvested at increasing times post-implantation, and the in vivo thickness loss, mass loss, and the drug release profiles were compared with their in vitro counterparts. The sequential release of four different drugs observed in vitro was successfully translated to in vivo conditions. Results suggest, however, that the total erosion time of the devices was longer and that release rates of the four drugs were different, with drugs initially released more quickly and then more slowly in vivo. Many comparative studies of in vitro and in vivo drug release from biodegradable polymers involved a single drug, whereas this research demonstrated that sequential release of four drugs can be maintained following implantation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1302-1310, 2016.

Transcriptome Analysis of B Cell Immune Functions in Periodontitis: Mucosal Tissue Responses to the Oral Microbiome in Aging.

Evidence has shown activation of T and B cells in gingival tissues in experimental models and in humans diagnosed with periodontitis. The results of this adaptive immune response are noted both locally and systemically with antigenic specificity for an array of oral bacteria, including periodontopathic species, e.g., Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. It has been recognized through epidemiological studies and clinical observations that the prevalence of periodontitis increases with age. This report describes our studies evaluating gingival tissue transcriptomes in humans and specifically exploiting the use of a non-human primate model of naturally occurring periodontitis to delineate gingival mucosal tissue gene expression profiles focusing on cells/genes critical for the development of humoral adaptive immune responses. Patterns of B cell and plasmacyte genes were altered in aging healthy gingival tissues. Substantial increases in a large number of genes reflecting antigen-dependent activation, B cell activation, B cell proliferation, and B cell differentiation/maturation were observed in periodontitis in adults and aged animals. Finally, evaluation of the relationship of these gene expression patterns with those of various tissue destructive molecules (MMP2, MMP9, CTSK, TNFα, and RANKL) showed a greater frequency of positive correlations in healthy tissues versus periodontitis tissues, with only MMP9 correlations similar between the two tissue types. These results are consistent with B cell response activities in healthy tissues potentially contributing to muting the effects of the tissue destructive biomolecules, whereas with periodontitis this relationship is adversely affected and enabling a progression of tissue destructive events.