Endodontics, Periodontics,
Oral Medicine, Oral Pathology 1996

Primary Sjogren’s syndrome presents with the symptoms of dry eyes and dry mouth. Secondary Sjogren’s, in addition, has an associated rheumatologic condition. It is an autoimmune exocrinopathy of unknown etiology, although viruses have been proposed. Fifteen archived samples of minor (labial) salivary gland tissue from histopathologically diagnosed Sjogren’s patients and fifteen archived samples diagnosed as mucocoeles (controls) were examined to evaluate the presence of human papilloma virus (HPV), Epstein Barr virus (EBV), and cytomegalovirus (CMV). All samples were formalin-fixed and embedded in paraffin. DNA was extracted from 50 mm formalin-fixed paraffin embedded tissue sections (Puregene DNA Isolation Kit, Gentra Systems, Inc.) and amplified by polymerase chain reaction techniques (PCR). PCR products were visualized on either polyacrylamide gels using a 373 ABI Automated DNA sequencer or in agarose/ethidium bromide gels. To insure that DNA extracts performed in the PCR, they were amplified for the exon 8 fragment of the P53 gene and for a T-cell receptor gene. Although positive reactions were seen with these markers, no evidence of EBV or CMV DNA was found. Evidence of HPV DNA was found in mucocoeles and Sjorgren’s tissue samples but the results were not significantly different.

ANTIBACTERIAL EFFECTIVENESS OF INTRACANAL PASTE MEDICAMENTS
LCDR Gary Cummings, DC, USN

The antibacterial activity of three intracanal paste medicaments were tested against other oral bacteria using a drop plate diffusion assay method. The antibacterial capability of Calacept, a calcium hydroxide paste (Scania Dental AB, Kinvsta, Sweden), Vitapex, a calcium hydroxide/iodoform paste (Neo Dental Chemical Products., LTD., Japan), and Endocalax, a calcium oxide/ethylene glycol paste (Nuova Adriadental, Italy) were measured. These materials were all compatible with ideal temporary canal filling properties including a significant decrease in apical leakage as compared to untreated canals, biocompatibility, and ease of placement into the canals. Controls included sterile distilled water and material solvents. Bacteria were selected for testing due to their predominance in periapical infections. Zones of bacterial growth inhibition were measured in millimeters (mm) using a dial caliper. Calacept and Endocalax inhibited growth of the facultative anaerobes tested (Lactobacillus casei, Enterococcus faecium, and Actinomyces viscosus). Vitapex had no effect on the growth of Enterococcus faecium but inhibited the growth of Lactobacillus casei and Actinomyces viscosus. Calacept and Endocalax were marginally effective against one of the obligate anaerobes tested (Prevotella intermedius). Vitapex inhibited the growth of all three obligate anaerobes (Prevotella intermedius, Viellonella parvula, and Peptococcus niger).

EFFECT OF TIME ON RADIOGRAPHIC DIAGNOSIS OF CARIES IN PHASED DENTISTRY
LCDR Wendy Hupp, DC, USN

The Navy Dental Corps has initiated a managed approach to the delivery of dental treatment. This program, Phased Dentistry, provides urgent care to new recruits while in basic training and defers non-urgent care until they have reported to their permanent duty station. Guidelines have been developed for the diagnosis of phase I (urgent) and phase II needs, with the goal of an 85% interexaminer agreement. This study compares the diagnosis of interproximal caries from bitewing radiographs immediately before and after a brief training session addressing these guidelines, and again 6 months later. Army and Air Force dentists were also surveyed. Navy dentists correctly answered a mean 69.8% of the time before training, 92.2% immediately after training, and 77.4% at 6 months post-training. Army and Air Force dental officers correctly answered a mean 74.1% and 81.2% of the time, respectively, without training. Although there was a statistically significant difference among the services for caries diagnosis based on Department of Defense guidelines, there may not have be a clinically significant difference based on the limited sample size in the survey. None of the services was consistently above the 85% threshold. The brief training session for Navy dentists was adequate to raise correct diagnoses above 85% agreement with decisions made by a panel of calibrated expert diagnosticians; however, consistent compliance with Phased Dentistry guidelines for radiographic diagnosis of caries was not evident at 6 month re-evaluation.

HEAT GENERATION DURING ULTRASONIC INSTRUMENTATION OF DENTIN AS AFFECTED BY DIFFERENT IRRIGATION METHODS
LDCR Robert J. Peters, DC, USN

Heat produced by ultrasonic scalers may cause injury to pulpal and periodontal tissues. Organisms in ultrasonic scaler coolant from the public water supply do not appear to contribute significantly to the incidence of bacteremia in healthy patients during non-surgical procedures. However, sound practice requires the use of a sterile coolant for ultrasonic scaling during surgery. Intermittent bulb irrigation is a way to deliver sterile water when using ultrasonic devices not equipped with a reservoir. The purpose of this study was to compare heat generation in dentin during ultrasonic scaling as affected by different irrigation methods. Dentinal/cemental slabs of 0.5, 1.0, 1.5, 2.0 and 2.5 mm thickness were prepared from 100 human molars. A 3.0 mm X 1.5 mm field was outlined on each slab to indicate the intended area of instrumentation. Each slab was mounted such that a thermocouple placed in contact with dentin opposite the area of instrumentation was shielded from irrigation. Twenty samples of each thickness were ultrasonically scaled during which dentin temperature was recorded every 5 seconds over a 30 second operating period. All 100 slabs were first treated with dental unit public water irrigation, followed by no irrigation; and finally by bulb irrigation with sterile saline. Dentin temperature was found to increase with decreasing slab thickness, and increased with duration of instrumentation regardless of treatment group. Repeated measures ANOVA indicated a statistically significant difference among irrigation techniques for temperature change (p<0.001). However, only a lack of irrigation produced a clinically significant rise in dentin temperature. Bulb irrigation delivered as a continuous drip appears equivalent to ultrasonic dental unit water spray for cooling during ultrasonic scaling at surgery.

COMPARISON OF A PARTICULATE AND BLOCK PREPARATION OF DECALCIFIED FREEZE-DRIED BONE ALLOGRAFTS IN HUMAN PERIODONTAL BONE DEFECTS: A PILOT STUDY
LCDR James D. Hoag, DC, USN

The purpose of this study was to evaluate bone fill and defect resolution in osseous defects associated with severe adult periodontitis following treatment with two different preparations of demineralized bone allograft. A particulate preparation of decalcified cortical freeze dried bone allograft (DFDBA) was compared to a Cloward dowel (CD) block preparation, consisting of decalcified freeze dried cancellous bone with a cortical veneer facing. The CD was specifically oriented at the time of surgery to allow the cortical veneer to serve in a membrane or barrier capacity. Eight defect pairs in 8 patients of comparable interproximal intrabony defects comprised the study group. Measurements with calibrated periodontal probes were obtained to determine soft tissue recession, probing depth (PD), and clinical attachment levels (CAL). Defects within each pair were randomly selected for treatment with either DFDBA or CD. Intraoperatively, additional measurements determined existing crestal bone levels and the vertical and horizontal dimensions of the osseous defects. Nine months following the initial surgical treatment, each site was reentered with all soft and hard tissue measurements repeated. Descriptive statistical analysis revealed that there were no differences between groups at baseline. Both treatments resulted in significant within group defect fills, attachment level gains, and probing depth reductions, however there was no difference between groups with these same parameters. Change in PD reductions for DFDBA were 4.1 mm + 2.4 and CAL gains were 3.1 mm + 2.3. PD reductions for the CD were 2.9 mm + 1.0 and CAL gains were 2.0 mm + 1.7. Based on this pilot study’s findings, the CD was at least as effective as DFDBA in the osseous fill of interproximal defects. The CD may offer the advantages of easier placement at the time of surgery, better graft containment during healing, and the concurrent placement of a barrier with defect abalation.

T-CELL RECEPTOR V mRNA EXPRESSION IN PATIENTS WITH SEVERE PERIODONTAL DISEASENTS
LCDR Keith Sonnier, DC, USN

The purpose of this investigation was to further evaluate superantigens as etiological agents in the development of periodontal disease. Superantigens activate T-cells by binding to V T-cell receptors (TCR) resulting in T-cell stimulation. TCR V mRNA expression was analyzed in peripheral blood lymphocytes from 12 patients with advanced periodontitis and 12 non-diseased patients. Total RNA was extracted from cells stimulated with anti-CD3. cDNA's were produced by reverse transcription and amplified using 22 V specific primers. V mRNA expression was quantified by polymerase chain reaction techniques (PCR). To quantify the relative amounts of V mRNA, the amount of a control product (C ) was used to normalize each variable product (V ) for differences in starting template concentrations. When TCR mRNA was assessed as a ratio of the expression of the specific V and C region, there were no significant differences (P > 0.05) in V expression between diseased and non-diseased patients. The data were reanalyzed and the expression of specific TCR V mRNA was assessed as a percentage of total TCR V mRNA expressed. Again, there were no significant differences observed between diseased and non-diseased patients. Also, expression of the 22 V subfamilies were disproportionate in both diseased and non-diseased patients.

COMPARISON OF CANAL TRANSPORTATION IN CURVED CANALS USING A NEW ROTARY HANDPIECE VERSUS BALANCED FORCE FILING
LCDR Jason Devey, DC, USN

Root canal transportation is the undesirable change in the shape of the apical portion of the canal occurring during instrumentation. The Endomatic is a cordless rechargeable handpiece that accepts files and burs that fit any latch-type contraangle and rotates in a counterclockwise direction. When used with the nickle-titanium S-files it provides rather aggressive cutting ability but does not result in significant apical canal transportation. The handpiece provides enough torque to adequately instrument canals but is under powered for use with conventional burs or Gates Glidden drills. This study compared the ability of two root canal instrumentation techniques to enlarge and maintain the curvature in mesial roots of mandibular molars. Forty-two mandibular molars were matched into pairs according to root length and curvature. One tooth from each pair was instrumented using the Endomatic handpiece, with nickel-titanium S-type files, and the other using the balanced force hand instrumentation technique with Flex-R files. Canal curvature maintenance was determined using a double exposure radiographic technique which allowed superimposition of working length (#10 file) and master apical file (#30 file) exposures. The radiographs were projected and the amount of apical transportation was categorized as either none (one file visible at the apex), moderate (two files visible at the apex without separation of the file tips), or severe (two distinct file tips visible). Evaluation of the radiographs was done by three board certified endodontists. Chi square analysis indicated no statistically significant difference between the techniques with regard to the amount of transportation.

A COMPARISON OF THE CLEANING EFFICACY OF PASSIVE SONIC ACTIVATION VERSUS PASSIVE ULTRASONIC ACTIVATION AFTER HAND INSTRUMENTATION IN MOLAR ROOT CANALS
LCDR Scott A. Jensen, DC, USN

Research has shown that root canal cleanliness is improved if ultrasonic instruments are used for 3 minutes after hand instrumentation. The purpose of this study was to determine if 3 minutes of passive sonic activation following hand instrumentation would produce canal cleanliness comparable to that of the higher frequency ultrasonics. Sixty molar canals with curvatures of 25 to 35 degrees were instrumented to size #35, using a balanced force technique with 5.25% NaOCl irrigation, followed by step-back flaring to size #55. Following hand instrumentation the canals were randomly divided into three groups of 20. Group 1 received no further treatment except additional placement of NaOCl in the canal for 3 minutes. Group 2 received 3 minutes of passive sonic activation using an MM1500 sonic handpiece and a # 15 Ripsisonic file placed 2 mm short of the working length. Group 3 received 3 minutes of passive ultrasonics using a #15 file in a MiniEndo ultrasonic handpiece. The roots were split and photomicrographs were made of the apical 6 mm of canal space at 20X magnification. The photomicrographs were projected to a size 24X that of the photomicrographicl transparency and overlaid by a transparent grid. Debris score was determined as the percentage of the number of squares overlying the apical 6 mm of the canal that contained debris. Group 1 canals had a mean debris score of 33.6%, while the mean debris scores for Group 2 and 3 were 19% and 17.6%, respectively. Canals passively treated with ultrasonic or sonic instruments were significantly cleaner than those treated with hand instrumentation alone. There was no significant difference between the sonic and ultrasonic groups. Passive sonic instrumentation following hand instrumentation produces a cleaner canal than hand instrumentation alone and is comparable to that of passive ultrasonic instrument use.

EFFECT OF TUMOR NECROSIS FACTOR AND ODONTOPATHIC BACTERIAL EXTRACTS ON CYTOKINE EXPRESSION IN HUMAN PULPAL AND GINGIVAL FIBROBLASTS
CDR James E. Pastor, DC, USN

Cytokines have significant and complex roles in inflammation and wound healing. Lymphocytes, macrophages, and fibroblasts can produce these mediators. In this study, we measured the extracellular levels of interleukin-1 (IL-1 ), interleukin-6 (IL-6) and interleukin-8 (IL-8) and intracellular mRNA expression for these cytokines in stimulated fibroblast cultures (ATCC gingival fibroblasts, OT-1 fibroblast tumor cells, and human gingival and human pulpal fibroblasts). Pulpal (PF)and gingival (GF) fibroblasts were obtained and cultured from patients at the National Naval Dental Center. Confluent cell cultures were stimulated for 24 hours with bacterial extracts of Actinobacillus actinomycetemcomitans (A.a.) and Porphyromonas gingivalis (P.g.), and tumor necrosis factor- (TNF- ) and tumor necrosis factor- (TNF- ). Culture supernatants were measured by ELISA to quantify secreted cytokine products. Fibroblast RNA was analyzed for gene expression products using a semi-quantitative reverse transcriptase polymerase chain reaction technique (RT-PCR). There was no induction of IL-1 in any of the cell lines and with any of the stimulators tested when measured by ELISA. However, using RT-PCR, IL-1 mRNA was identified in ATCC fibroblasts, GF, and PF following P.g. and A.a. stimulation. IL-6 and IL-8 were significantly elevated in GF, PF and ATCC fibroblast culture supernatants following stimulation by A.a. and P.g. PF levels were 5- to 10-fold greater than those in GF cultures. IL-6 and IL-8 levels were also elevated following stimulation with TNF- and TNF- . Cytokine production by PF was 10-fold greater than that observed with GF.