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.

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.

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.

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.

Effect of Bisphosphonate and Age on Implant Failure as Determined by Patient-Reported Outcomes.

The aim of the current study was to elucidate whether there is an association between selected risk factors and implant failure, as determined by patient-reported outcomes. A trained clinician administered a formal survey questionnaire to 415 patients who had received a total of 963 implants through the University of Kentucky College of Dentistry's implant training program. The questionnaire was designed to obtain information about potential risk factors that may affect implant failure. Patients were also asked to rate their satisfaction with the appearance and function of the implant, their surgical experience, and the levels of pain and mobility associated with the implant(s). Both patient-level and implant-level data were analyzed in this study. Multiple logistic regression analysis at the patient level indicated that the following variables did not contribute to the success or failure of the implants: sex, smoking status, diabetes, osteoporosis, and use of bisphosphonates. When the statistical analyses controlled for these variables, the odds of patient-reported implant failure increased with the patient's age (by 15% every 5 years). The results of implant-level analyses adjusted for smoking status, diabetes, and osteoporosis showed that the patient's age (odds of failure increased by 12% every 5 years) and no use of bisphosphonates (odds ratio, 9.22; 95% confidence interval, 1.849, 45.975) were significantly associated with poor implant outcome. Our findings suggest a possible association between implant failure and the patient's age and use of bisphosphonates.

Programmatic assessment of a university-based implant training program using patient-reported outcomes.

The University of Kentucky College of Dentistry (UKCD) established an implant training program that provides training in the use of a single implant system, evidence-based diagnostic and treatment protocols (standardized work practices), and a total quality management system (Implant Quality Assurance Program). The aim of this study was to assess the programmatic effectiveness of the UKCD implant training program by reporting the success and survival of implants placed, using patient-reported outcomes and comparing them to previously established benchmarks. A total of 415 patients (963 implants) were interviewed, approximately 50 percent of all qualified patients. The implant survival rate was 97 percent, and 88 percent of the implants were considered successful (as determined by patient-centric criteria). These outcomes were consistent with the program's previously established benchmarks of 90 percent. These results suggest that work standardization (in the form of specific treatment protocols) and the use of a formal, incremental learning system can result in positive patient outcomes. Clinical outcomes should be monitored in academic dental settings as part of clinical process improvement, and these outcomes can provide a means of assessing the effectiveness of the training program.

Bioerodible system for sequential release of multiple drugs.

Because many complex physiological processes are controlled by multiple biomolecules, comprehensive treatment of certain disease conditions may be more effectively achieved by administration of more than one type of drug. Thus, the objective of the present research was to develop a multilayered, polymer-based system for sequential delivery of multiple drugs. The polymers used were cellulose acetate phthalate (CAP) complexed with Pluronic F-127 (P). After evaluating morphology of the resulting CAPP system, in vitro release of small molecule drugs and a model protein was studied from both single and multilayered devices. Drug release from single-layered CAPP films followed zero-order kinetics related to surface erosion of the association polymer. Release studies from multilayered CAPP devices showed the possibility of achieving intermittent release of one type of drug as well as sequential release of more than one type of drug. Mathematical modeling accurately predicted the release profiles for both single layer and multilayered devices. The present CAPP association polymer-based multilayer devices can be used for localized, sequential delivery of multiple drugs for the possible treatment of complex disease conditions, and perhaps for tissue engineering applications, that require delivery of more than one type of biomolecule.

Design of a multiple drug delivery system directed at periodontitis.

Periodontal disease is highly prevalent, with 90% of the world population affected by either periodontitis or its preceding condition, gingivitis. These conditions are caused by bacterial biofilms on teeth, which stimulate a chronic inflammatory response that leads to loss of alveolar bone and, ultimately, the tooth. Current treatment methods for periodontitis address specific parts of the disease, with no individual treatment serving as a complete therapy. The present research sought to demonstrate development of a multiple drug delivery system for stepwise treatment of different stages of periodontal disease. More specifically, multilayered films were fabricated from an association polymer comprising cellulose acetate phthalate and Pluronic F-127 to achieve sequential release of drugs. The four types of drugs used were metronidazole, ketoprofen, doxycycline, and simvastatin to eliminate infection, inhibit inflammation, prevent tissue destruction, and aid bone regeneration, respectively. Different erosion times and adjustable sequential release profiles were achieved by modifying the number of layers or by inclusion of a slower-eroding polymer layer. Analysis of antibiotic and anti-inflammatory bioactivity showed that drugs released from the devices retained 100% bioactivity. The multilayered CAPP delivery system offers a versatile approach for releasing different drugs based on the pathogenesis of periodontitis and other conditions.

Bioerodible calcium sulfate/poly(ß-amino ester) hydrogel composites.

The capacity to quickly regenerate or augment bone lost as a result of resorption is crucial to ensure suitable application of prosthetics for restoring masticatory function. Calcium sulfate hemihydrate (CS)-based bone graft substitute composites containing poly(ß-amino ester) (PBAE) biodegradable hydrogel particles were developed to act as a 'tenting' barrier to soft tissue infiltration, potentially providing adequate space to enable vertical bone regeneration. CS has long been recognized as an osteoconductive biomaterial with an excellent reputation as a biocompatible substance. Composite samples were fabricated with varying amounts (1 or 10 wt%) and sizes (53-150 or 150-250 µm) of gel particles embedded in CS. The swelling and degradation rates of PBAE gels alone were rapid, resulting in complete degradation in less than 24h, an important characteristic to aid in controlled release of drug. MicroCT images revealed a homogeneous distribution of gel particles within the CS matrix. All CS samples degraded via surface erosion, with the amount of gel particles (i.e., 10 wt% gel particles) having only a small, but significant, effect on the dissolution rate (4% vs. 5% per day). Compression testing determined that the amount, but not the size, of gel particles had a significant effect on the overall strength of the composites. As much as a 75% drop in strength was seen with a 10 wt% loading of particles. A pilot study using PBAE particles loaded with the multipotential drug curcumin demonstrated sustained release of drug from CS composites. By adjusting the amount and/or size of the biodegradable gel particles embedded in CS, mechanical strength and degradation rates of the composites, as well as the drug release kinetics, can be tuned to fabricate, multi-functional 'space-making' bone grafting substitutes.

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.

Factors influencing the periodontal referral process.

BACKGROUND: General dental practitioners (GPs) assess the periodontal status of patients and make decisions to treat patients or refer them to a periodontist. There is little information available regarding this process. The purpose of this study is to identify significant factors that GPs consider important in selecting a particular periodontist. The findings were compared and contrasted with responses of periodontists to gain perspectives from both groups involved in the referral process. METHODS: Data from an online cross-sectional survey of GPs (n = 533) and periodontists (n = 533) who practice in the southeastern region of the United States (from the databases of the American Dental Association and American Academy of Periodontology member directories) were obtained. RESULTS: The specialist's clinical skill was identified as the most important factor influencing periodontal referrals by GPs, whereas periodontists identified a previous positive experience between a GP and periodontist as the most important factor. In a descending order of importance, the top three rating averages (rated out of five) by GPs were clinical skill (4.84), a previous positive experience between a GP and periodontist (4.57), and communication (4.52). The top three factors of periodontists were a previous positive experience between a GP and periodontist (4.66), communication (4.40), and the likelihood of a good patient and periodontist rapport (4.29). CONCLUSIONS: The periodontist's clinical skill was chosen by GPs as the primary factor influencing the referral decisions of GPs. Periodontists perceived a previous positive experience between the GP and periodontist as the most influential factor. Further studies are required to gain more insight into the referral process.

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.

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.

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.

Evidence-based curriculum reform: the Kentucky Experience.

Evidence-based health care seeks to base clinical practice and decision-making on best evidence, while allowing for modifications because of patient preferences and individual clinical situations. Dentistry has been slow to embrace this discipline, but this is changing. In the Graduate Periodontology Program (GPP) of the University of Kentucky, an evidence-based clinical curriculum was implemented in 2004. The tools of evidence-based health care (EBHC) were used to create evidence-based protocols to guide clinical decision-making by faculty and residents. The program was largely successful, although certain challenges were encountered. As a result of the positive experience with the GPP, the college is implementing a wider program in which evidence-based protocols will form the basis for all patient care and clinical education in the predoctoral clinics. A primary component of this is a computerized risk assessment tool that will aid in clinical decision-making. Surveys of alumni of the periodontal graduate program show that the EBHC program has been effective in changing practice patterns, and similar follow-up studies are planned to assess the effectiveness of the predoctoral EBHC program.

Evidence-based dentistry and the concept of harm.

Evidence-based medicine requires the integration of best research evidence with the clinician's expertise and the patient's unique values and circumstances. One of the most important issues in deciding what course of treatment to select is balancing the potential risks and benefits of treatment. A framework for evidence-based decision-making includes formulating the clinical question and then retrieving, appraising, and considering the applicability of the evidence to the patient. It is the duty of all health care providers to reduce patient risk by selecting appropriate therapies and informing patients of unavoidable risks.

In-office treatment of dentinal hypersensitivity.

Dentinal hypersensitivity is a common dental complaint, especially in periodontal patients. It is believed to be mediated by a hydrodynamic mechanism in which various stimuli result in increased fluid flow in dentinal tubules, thereby generating action potentials in associated nerve fibers. Although it is often perceived as mild discomfort by the patient, it can be severe. A variety of interventions has been used, although few have been subjected to rigorous study. This article surveys those in-office treatments that are available, and suggests directions for research so that clinicians may treat patients based on best evidence. Until such evidence is available, it seems prudent to employ therapies that are least likely to cause harm and are reversible.