David C. Holmes

Influence of post dimension on stress distribution in dentin

Stress distribution studies can be helpful in determining the appropriate diameter and length of endodontic posts for specific teeth in select occlusal relationships. This study selected the finite element method to predict distribution of stresses in dentin of an endodontically treated tooth restored with cast post and cores with various post dimensions. Peak dentinal shear stresses occurred adjacent to the post at mid-root. Peak shear stresses were elevated as the length of the post decreased. Peak dentinal tensile stresses occurred in the gingival third of the facial root surface, whereas peak dentinal compressive stresses were evident in the gingival third of the lingual root surface. The distribution of tensile and compressive stresses was not affected with variation in the dimensions of the posts.

Short-term fluoride release/uptake of glass ionomer restoratives

OBJECTIVES The short-term fluoride release/uptake of four glass ionomer restoratives was measured and compared to the fluoride release after exposure to three commercial fluoride gels. METHODS Materials tested were: 1) Ketac-Fil (ESPE GmbH); 2) Ketac-Silver (ESPE GmbH); 3) Photac-Fil (ESPE GmbH); and 4) Fuji II LC (GC Corp.). Twenty discs of each material were fabricated and stored in deionized water at 37 degrees C. Initial fluoride release was measured at 24 h intervals for 7 d, and 24 h intervals at the end of each week for 5 wk. After 6 wk, samples were divided into groups and each group was treated for 6 min with one of the following commercial fluoride gels: acidulated phosphate fluoride (APF), neutral sodium fluoride (NaF), and stannous fluoride (SnF2). Control specimens were placed in deionized water. After exposure, fluoride measurements were carried out at 24 h intervals for 7 d, and 24 h intervals at the end of 2 wk. Fluoride exposure was repeated, and measurements were again recorded over 3 wk. RESULTS Initial fluoride release by all materials was highest during the first 24 h and decreased sharply over the first week. After exposure to APF, fluoride release increased significantly for all materials. Exposure to NaF also resulted in increased fluoride release for all materials although it was not as high as the increase recorded after exposure to APF. Exposure to SnF2 did not result in significant fluoride release by any material. SIGNIFICANCE The results of this study suggest that certain fluoride gels may replenish fluoride within some glass ionomers and thus prolong their cariostatic potential.

An In Vitro Comparison of Vertical Marginal Gaps of CAD/CAM Titanium and Conventional Cast Restorations

PURPOSE To determine if there was a significant difference between the vertical marginal openings of cast restorations, computer-aided design, and computer-aided machining restorations. MATERIALS AND METHODS Ten working dies were created from a single master die and used to fabricate ten restorations in each of the following groups: computer-aided design/computer-assisted machining (CAD/CAM), WAX/CAM, and WAX/CAST. The CAD/CAM titanium restorations were fabricated using the scanning and crown design modules of the KaVo Everest system. The WAX/CAM titanium restorations were fabricated using the double scan technique with the KaVo Everest system. The WAX/CAST high noble copings were fabricated using the conventional lost wax casting technique. The restorations were seated on the master die, and high-resolution digital photographs were made of the marginal area on all four sides. The vertical marginal opening was then measured using a calibrated digital software program. One-way ANOVA and Tukeys post hoc tests were used to determine the presence of statistically significant differences. RESULTS The vertical margin openings were CAD/CAM: 79.43 +/- 25.46 microm; WAX/CAM: 73.12 +/- 24.15 microm; WAX/CAST: 23.91 +/- 9.80 microm. There was a statistically significant difference between the WAX/CAST group and the remaining groups. CONCLUSIONS There was no difference between the vertical marginal gaps of the CAD/CAM and WAX/CAM. The WAX/CAST technique resulted in smaller vertical marginal gaps than either CAD/CAM or WAX/CAM.

Complementary and alternative medicine usage by patients of a dental school clinic.

This pilot study investigated the prevalence and specific reasons for usage of complementary and alternative medicine (CAM) among patients of a dental school clinic. Four hundred and two patients completed a 30-page survey on CAM usage. A higher rate of CAM usage was found in this dental school clinic population than rates previously reported in a general population. More than three-quarters (76.1%) of the respondents reported using at least one CAM treatment in the past 12 months; 93.3% reported using at least one CAM treatment at some time in their lives. High rates of chiropractic use were found in this population. Tooth pain was the most frequently reported dental condition motivating CAM use. About 10% of dental school clinic patients use topical oral herbal and/or natural products to treat dental conditions, most frequently for preventive/oral health reasons or for tooth pain.

The Use of a Respiratory Rate Biofeedback Device to Reduce Dental Anxiety: An Exploratory Investigation

Anxiety experienced by individuals visiting the dental office to receive treatment is common. Evidence has shown biofeedback to be a useful modality of treatment for numerous maladies associated with anxiety. The purpose of the current pilot study was to investigate the use of a novel biofeedback device (RESPeRATE™) to reduce patients’ pre-operative general anxiety levels and consequently reduce the pain associated with dental injections. Eighty-one subjects participated in this study, forty in the experimental group and forty-one in the control group. Subjects in the experimental group used the biofeedback technique, while those in the control group were not exposed to any biofeedback. All subjects filled out a pre-injection anxiety survey, then received an inferior alveolar injection of local anesthetic. Post-injection, both groups were given an anxiety survey and asked to respond to four questions regarding the injection experience using a Visual Analog Scale (VAS). With the use of the respiratory rate biofeedback device, there was a significant reduction of negative feelings regarding the overall injection experience, as measured by a VAS. Our findings demonstrate that this novel biofeedback technique may be helpful in the amelioration of dental anxiety, and may help produce a more pleasant overall experience for the patient.

Maximising the potential of part‐time clinical teachers

Background:  A problem faced by health professions education throughout the world is a lack of full‐time clinical teachers. This is particularly serious in dentistry and nursing, but is increasingly also true in medicine. To make up for this shortfall there is a growing reliance on part‐time clinical teachers.

Patterns of complementary and alternative medicine (CAM) use among dental patients.

OBJECTIVES Complementary and alternative medicine (CAM) is a diverse collection of approaches used to prevent or treat diseases. The goal of this study was to examine relationships between dental patient characteristics and current usage of CAM therapies. METHODS The CAM definition encompassed 24 therapies excluding prayer. Associations and trends in usage were assessed for gender, income, education, and age. Multivariable logistic and negative binomial models were used to identify factors impacting the use and number of CAM therapies used. RESULTS In dental patients (n = 402), nearly 67 percent of subjects reported at least one CAM treatment. Gender was significantly associated with recent utilization of CAM, biological, manipulative (all P < 0.01), and mind-body (P = 0.04) therapies, as well as the number (P < 0.01) of therapies used. Higher education levels were significant in usage of any CAM, biological, and mind-body therapies (P < 0.01). CONCLUSION A large proportion of dental patients reported use of CAM therapies. While CAM therapies and those who use them are diverse, given their widespread use, they clearly have potential impacts on the oral health of the public. Knowledge of the characteristics of dental patients who use CAM therapies is a first step in developing a broader understanding how CAM therapies and associated beliefs may affect oral health and public health programs.

Retention and recruitment of general dentists in an adjunct teaching model—A pilot study

Purpose/Objectives Retention and recruitment of part time clinical adjunct faculty members in dental education is becoming increasingly difficult as dental schools come to rely on this workforce for their increased involvement in clinical education. Contributing factors include full time faculty shortage, aging workforce, practice and student debt, practice and family commitments, and financial compensation. This study attempts to ascertain barriers to teaching so appropriate strategies can be formulated to address this issue. Methods In the spring of 2016 an email survey was sent to current and former adjunct faculty members to ascertain demographics and retention and recruitment strategies. Descriptive analyses were completed for all variables in the sample. Results Twenty nine of forty six subjects responded to the survey with a response rate of 63%. Subjects over the age of sixty comprised 55% with only 17% being under the age of forty five. Overall family and practice commitments along with compensation were the primary barriers to teaching part time. For new dentists, student loan debt was the primary barrier to teaching. Travel to teach was also a barrier as 70% of respondents drove 200 miles or less to the dental school. Conclusion The study demonstrated that the aging part time work force is a great concern and new part time clinical adjunct faculty members must be recruited. Barriers to recruitment and retention of faculty must be considered and addressed to sustain this teaching model.