A pilot study of ambulatory masticatory muscle activities in temporomandibular joint disorders diagnostic groups.

OBJECTIVE: To determine differences in masticatory muscle usage between temporomandibular joint disorders diagnostic groups. SETTING AND SAMPLE POPULATION: Seventy-one informed and consented subjects (27 men; 44 women) participated at the University at Buffalo. MATERIAL AND METHODS: Research diagnostic criteria and imaging data were used to categorize subjects according to the presence/absence +/- of TMJ disc placement (DD) and chronic pain (P) (+DD+P, n=18; +DD-P, n=14; -DD-P, n=39). Electromyographic (EMG)/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20 N bite-force (T20N , µV). Over 3 days and nights, subjects collected EMG recordings. Duty factors (DFs, % of recording time) were determined based on threshold intervals (5-9, 10-24, 25-49, 50-79, ≥80% T20N ). anova and Tukey-Kramer post hoc tests identified 1) diagnostic group differences in T20N and 2) the effects of diagnostic group, gender, time and interval on muscle DFs. RESULTS: Mean (±SE) temporalis T20N in +DD+P subjects was significantly higher (71.4±8.8 µV) than masseter T20N in these subjects (19.6±8.8 µV; p=0.001) and in -DD-P subjects (25.3±6.0 µV, p=0.0007). Masseter DFs at 5-9% T20N were significantly higher in +DD-P women (3.48%) than +DD-P men (0.85%) and women and men in both other diagnostic groups (all p<0.03), and in +DD+P women (2.00%) compared to -DD-P men (0.83%; p=0.029). Night-time DFs at 5-9% T20N in +DD-P women (1.97%) were significantly higher than in -DD-P men (0.47%) and women (0.24%; all p<0.01). CONCLUSIONS: Between-group differences were found in masticatory muscle activities in both laboratory and natural environmental settings.

Diagnostic group differences in temporomandibular joint energy densities.

OBJECTIVES: Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm³) in TMJs of three diagnostic groups. SETTING AND SAMPLE POPULATION: Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD). MATERIAL AND METHODS: Subjects (+P+DD, n=16; -P+DD, n=16; and -P-DD, n=36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q (W=work done or mechanical energy input=tractional force×distance of stress-field translation, Q=volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences. RESULTS: Mean±standard error energy density for the +P+DD group was 12.7±1.5 mJ/mm³ and significantly greater (all adjusted p<0.04) when compared to -P+DD (7.4±1.4 mJ/mm³) and -P-DD (5.8±0.9 mJ/mm³) groups. Energy densities in -P+DD and -P-DD groups were not significantly different. CONCLUSION: Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.

Modeling of muscle forces in humans with and without temporomandibular joint disorders.

OBJECTIVES: Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. SETTING AND SAMPLE POPULATION: School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). MATERIAL AND METHODS: Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations. RESULTS: +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p<0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8). CONCLUSION: Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.

Effects of local simvastatin-alendronate conjugate in preventing periodontitis bone loss.

BACKGROUND AND OBJECTIVE: Local host-modulation therapy is an emerging approach to prevent disease progression in sites with moderate periodontitis. The combination of simvastatin and alendronate would be an intriguing host-modulatory strategy because of the bone-anabolic properties of simvastatin and the antiresorptive/bone-targeting characteristics of alendronate. The objective of this study was to evaluate the effects of local administration of a simvastatin-alendronate-ß-cyclodextrin (SIM-ALN-CD) conjugate for preventing experimental periodontitis bone loss. MATERIAL AND METHODS: Twenty-four mature female Sprague-Dawley rats were treated with three, 12 µL injections, administered one week apart, bilaterally into the palatal/interproximal gingiva. The injections contained: (i) a conjugate of 0.5 mg of SIM and 3.75 mg of ALN-CD in H2 O; (ii) H2 O alone; or (iii) no treatment. One week later, the same sites were subjected to induction of experimental periodontitis by three injections (i.e. one injection administered every other day for five d) of 0.01 mg of Escherichia coli endotoxin [lipopolysaccharide (LPS)] in phosphate-buffered saline (PBS) or PBS alone. After an additional week, the rats were killed, the palates were harvested and interproximal bone volume and adjacent thickness were calculated using microcomputed tomography. Subsequently, specimens were decalcified, and interproximal histologic sections were stained with hematoxylin and eosin for evaluation of alveolar crest osteoclasts and surrounding inflammation. Values were compared among treatment groups using analysis of variance and the Kruskal-Wallis test. RESULTS: Interproximal bone volume was reduced by LPS injections (p ≤ 0.04), yet when experimental periodontitis was preceded by treatment with SIM-ALN-CD, more bone was preserved than after treatment with carrier alone (p = 0.007). While LPS caused a significant loss in bone thickness over the palatal roots (p ≤ 0.04), the injection protocol (PBS) also caused a significant loss of palatal bone thickness (p ≤ 0.03). However, prophylactic SIM-ALN-CD injections resulted in no further loss of bone thickness during experimental periodontitis. LPS injections gave histologic evidence of increased osteoclasts and subsulcular inflammation, both of which were reduced when preceded by treatment with SIM-ALN-CD (p ≤ 0.0002). CONCLUSION: The primary conclusion of this study was that locally applied SIM-ALN-CD has the potential to prevent episodes of periodontitis bone loss.

Muscle organization in individuals with and without pain and joint dysfunction.

Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. Evaluations of diagnostic group and gender effects on choice of best-fit model were by analysis of variance (ANOVA) and Tukey-Kramer post hoc tests, evaluations of right-left symmetry were by Chi-square and Fisher's exact statistics, and evaluations of model accuracy were by within-subject linear regressions. MME was the best-fit during left molar biting in +DD individuals and incisor biting in men (all p < 0.03). Incisor biting symmetry in muscle organization was significantly higher (p < 0.03) in healthy individuals compared with those with TMD. Within-subject regressions showed that best-fit model errors were similar among groups: 8 to 15% (0.68 ≤ R(2) ≤ 0.74). These computer-assisted models predicted muscle organization during static biting in humans with and without TMDs.

Human temporomandibular joint eminence shape and load minimization.

Analysis of previous data suggested the hypothesis that temporomandibular joint (TMJ) eminence shapes develop ideally to minimize joint loads. Hence, we tested this hypothesis in nine females and eight males in each of two groups, with and without TMJ disc displacement. Participants provided anatomical data used in a joint load minimization numerical model to predict, and jaw-tracking data used to measure, eminence shapes. Coordinate data (x,y) of shapes were fit to third-order polynomials for two sessions, sides, and methods (predicted, measured) for each participant. Inter-session data were reliable and averaged. Those with, compared with those without, disc displacement had higher measured shape range (5:1) and left-right asymmetry prevalence (4:1). In 29 symmetrical individuals, ANCOVA and Bonferroni tests compared vertical dimensions (y) at 11 postero-anterior points (x), 0.5 mm apart. Model-predicted and measured shapes were significantly different (P < or = 0.01) near the eminence crest, but joint load minimization was consistent with eminence shape for x < 3.0 mm.

Tractional forces on porcine temporomandibular joint discs.

Tractional forces on the temporomandibular joint (TMJ) disc predispose tissue fatigue. This study tested the hypotheses that tractional forces: (1) increased with stress-field velocity (V) and aspect ratio (AR, contact area diameter/cartilage thickness), and compressive strain (epsilon); and (2) varied depending on cartilage thickness. Porcine TMJ discs (n = 187) received a 10-N vertical static load via an acrylic indenter for 1, 5, 10, 30, or 60 sec, followed by movement. Physical data were recorded and analyzed by quadratic regression relations and a likelihood ratio test. Results showed non-linear increases in tractional forces that were positively correlated with increased V, AR, and epsilon when the stress-field moved onto relatively thicker (R(2) = 0.83) and thinner cartilage (R(2) = 0.86). When V was > 27 mm/sec and AR.epsilon(3), was > 0.09, tractional forces were significantly higher (< or = 12% of peak) when the stress-field moved onto thicker cartilage. Stress-field dynamic mechanics and cartilage thickness significantly affected TMJ disc tractional forces.

IL-1 gene polymorphisms, secretion in gingival crevicular fluid, and speed of human orthodontic tooth movement.

OBJECTIVES: To investigate genetic, biologic, and mechanical factors that affect speed of human tooth movement. Setting and Sample Population - Sixty-six maxillary canines in 33 subjects were translated distally for 84 days. MATERIAL AND METHODS: Distal compressive stresses of 4, 13, 26, 52, or 78 kPa were applied to maxillary canines via segmental mechanics. Dental casts and gingival crevicular fluid (GCF) samples were collected nine to 10 times/subject over 84 days at 1- to 14-day intervals. Three-dimensional tooth movements were measured using a microscope and each subject's series of dental casts. GCF samples were analyzed for total protein, interleukin-1beta (IL-1beta), and interleukin-1 receptor antagonist (IL-1RA). Cheek-wipe samples from 18 subjects were typed for IL-1 gene cluster polymorphisms. RESULTS: Average speeds of distal translation were 0.028 +/- 0.012, 0.043 +/- 0.019, 0.057 +/- 0.024, 0.062 +/- 0.015, and 0.067 +/- 0.024 mm/day for 4, 13, 26, 52, and 78 kPa, respectively. Most teeth moved showed no lag phase (63/66). Three factors significantly affected speed (p = 0.0391) and provided the best predictive model (R(2) = 0.691): Activity index [AI = experimental (IL-1beta/IL-1RA)/control (IL-1beta/IL-1RA)], IL-1RA in GCF, and genotype at IL-1B. CONCLUSIONS: Increased AI and decreased IL-1RA in GCF plus having > or =1 copy of allele 2 at IL-1B(+3954) were associated with faster tooth movement in humans.

Variations in activities of human jaw muscles depend on tooth-tipping moments.

Static mechanical analyses of the masticatory apparatus often assume that jaw muscle activity, as measured using electromyography (EMG), is linearly and constantly related to magnitude of bite force during biting, regardless of bite force-induced tooth-tipping moments. The objective of this study was to test the hypothesis that the relationship between EMG of the jaw muscles and bite force varies with the magnitude and sign of tooth-tipping moments. Seven healthy male subjects produced unilateral static occlusal forces at five biting positions, resulting in sequential changes from buccal (+) to lingual (-) tipping moments on the mandibular first molar. Jaw muscle activities were recorded bilaterally using surface (for temporalis and masseter muscles) and indwelling (for lateral pterygoid muscles) electrodes. Bite forces were recorded and controlled using custom devices. EMG versus bite force data were plotted and regression relationships were calculated for each subject, muscle and biting position. Linear regression analysis, analysis of variance and Bonferroni adjusted least significant difference tests were used to determine the effects of muscle, side (ipsilateral, contralateral) and biting position within subjects. It was found that the relationship between EMG and bite force for different tipping moments differed significantly within a subject and muscle. This was most common in the lateral pterygoid and temporalis muscles (all P25:1. In the masseter muscle, the EMG:bite force relationship for different tipping moments differed significantly in one subject (P<0.008); slopes varied up to 4.6:1. In conclusion, the relationship between EMG and bite force was linear. However, the slopes of the relationship changed significantly depending on sign (+, -) and magnitude of tipping moments acting on the molars.

Cyclooxygenase-2 inhibitor reduces simvastatin-induced bone morphogenetic protein-2 and bone formation in vivo.

BACKGROUND AND OBJECTIVE: Simvastatin, a cholesterol-lowering drug, also stimulates oral bone growth when applied topically, without systemic side-effects. However, the mechanisms involved in vivo are not known. We hypothesized that bone morphogenetic protein-2, nitric oxide synthase, and cyclooxygenase-2 are involved, based on prior in vitro evidence. MATERIAL AND METHODS: A rat bilateral mandible model, where 0.5 mg of simvastatin in methylcellulose gel was placed on one side and gel alone on the other, was used to quantify nitric oxide, cyclooxygenase-2 and bone morphogenetic protein-2 (via tissue extraction, enzyme activity or immunoassay), and to analyze the bone formation rate (via undecalcified histomorphometry). Cyclooxygenase-2 and nitric oxide synthase inhibitors (NS-398 and L-NAME, respectively) were administered intraperitoneally. RESULTS: Simvastatin was found to stimulate local bone morphogenetic protein-2, nitric oxide and the regional bone formation rate (p < 0.05), whereas NS-398 inhibited bone morphogenetic protein-2 and reduced the bone formation rate (p < 0.05). CONCLUSION: These data suggest an association between simvastatin-induced bone morphogenetic protein-2 and bone formation in the mandibular microenvironment, and the negative effect of cyclooxygenase-2 inhibitors on bone growth.

Static and dynamic loading effects on temporomandibular joint disc tractional forces.

UNLABELLED: Mechanical fatigue-related degeneration of the temporomandibular joint (TMJ) disc may be promoted by tractional forces. This study tested the hypotheses that tractional forces following static loading of the TMJ disc: (1) increase with compressive strain at the start of movement, and (2) are velocity-dependent during movement. Sixty-four porcine discs received a 10-N static load via an acrylic indenter for 1 or 30 sec before cyclic movement. Physical data were recorded and analyzed by ANOVA. The results showed that compressive strain and tractional forces were largest for the start of movement following 30 sec of static loading (p

Laboratory stresses and tractional forces on the TMJ disc surface.

The etiology of degenerative disease of the TMJ may involve fatigue produced by surface tractional forces and compressive stresses. This study tested the time-dependent effects of compressive loading and stress-field translation on TMJ disc-surface tractional forces and stresses. In laboratory experiments with 50 porcine discs, an acrylic indenter imposed 10 N static loads for 10 and 60 sec, followed by translation of the loaded indenter along the mediolateral axis of the disc. Maximum tractional forces were found to occur following 60 sec of static loading (p < 0.001), and increased with translation velocity (R(2) = 0.73); whereas maximum compressive stresses occurred after 10 sec of static loading (p < 0.001). Overall, the results were consistent with current mechanical theories of the time-dependent effects of compressive loading of cartilage.

Bone turnover markers in serum and periodontal microenvironments.

BACKGROUND: Periodontitis is characterized by altered bone turnover, but local measurements are difficult. OBJECTIVES: The objective of this study was to develop a method to measure multiple markers of bone turnover from single samples collected at various bone surfaces of the periodontium, and to test the ratios of these markers against more traditional serum and gingival crevicular fluid (GCF) samples. MATERIALS AND METHODS: Fourteen subjects with untreated periodontitis were recruited for sampling serum, GCF (from sites > or = 5 mm probing depth that bled on probing) and washes of periodontal bone surfaces (adjacent interproximal, vestibular cortical and trabecular bone) with a novel irrigating device. All samples were analyzed for osteocalcin (OC, bone turnover marker; RIA), cross-linked N-telopeptide of type I collagen (NTx, bone resorption marker; ELISA) and albumin (Alb, serum protein; ELISA). Results were reported as ratios: OC/NTx to determine relative bone turnover, and OC/Alb or NTx/Alb to determine local OC or NTx production. RESULTS: The OC/NTx ratio was significantly higher (p < or = 0.05) in serum vs. GCF (OC undetectable), interproximal bone and cortical vestibular bone, but significantly lower than in trabecular vestibular bone. The OC/Alb ratio for serum was also statistically lower than for vestibular trabecular bone. The NTx/Alb ratio for serum was statistically lower than for GCF and all the bone wash test sites. The results indicated considerable local production of both OC and NTx. CONCLUSIONS: This system demonstrated that multiple markers of bone turnover can be harvested by irrigation from periodontal bone microenvironments. Bone turnover profiles from periodontal bone surfaces and GCF differed from systemic bone turnover profiles (serum) and may be valuable in tracking site-specific responses to disease or treatment.

Effects of locally-delivered human macrophage products and estrogen on murine inflammatory bone resorption.

The objective of this study was to use an in vivo model of periodontitis (mouse calvaria) to quantify the effects of local release of secreted human macrophage products, 17beta-estradiol (E2), and proinflammatory lipopolysaccharide (LPS) on histologic bone resorption. Human THP-1 monocytes (106) were converted to macrophage phenotype by 500 ng/ml phorbol 12-myristate- 13-acetate (PMA) and treated as follows: no stimulation or Escherichia coli LPS (10 microg/ml) alone or in combination with a physiologic dose of E2 (100 pg/ml) for 24 h in RPMI/10% FBS, washed extensively, then incubated for 24 h in serum-free media. Supernatant products were concentrated and incorporated into a 4% (w/v) methylcellulose gel. Separate gels were incorporated with the following: LPS (500 microg/animal) alone, high dose of E2 (10 ng/animal) alone, a combination of LPS + E2, or gel only (controls). Loaded or control gels were placed into a polylactic acid occlusive dome, inserted subcutaneously over the calvaria of mature ovariectomized ICR Swiss mice (8 mice x 7 groups x 2 times [5/14 days] = 112 animals), then calvaria were evaluated histologically. Macrophage stimulation with LPS alone, but not LPS in combination with E2, produced supernatants which upregulated osteoclast numbers in the suture area compared to gel controls at 5 days (p = 0.009). The addition of LPS directly to the local delivery gels significantly upregulated osteoclasts in endosteal surfaces compared to gel controls at 5 days (p = 0.024) and at 14 days (p = 0.025). The addition of E2 to LPS down-regulated resorption to a level not different from gel controls at 14 days. This in vivo model appears effective in studying inflammatory bone resorption, which may be inhibited by E2 directly or through its influence on secreted macrophage products.

A cost of reproduction in Drosophila melanogaster: stress susceptibility.

Little is known about physiological mechanisms that underlie the cost of reproduction. We tested the hypothesis that stress susceptibility is a cost of reproduction. In one test of our hypothesis, Drosophila melanogaster females were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster was employed as a control for reproduction. Exposure of fertile females to methoprene resulted in an increase in female reproduction and increased susceptibility to oxidative stress and starvation (compared to solvent controls). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated egg production. As a second test of our hypothesis, mated females were compared to virgin females. Mated fertile females were relatively susceptible to oxidative stress, but this relationship was not evident when mated and virgin sterile females were compared. The results of the present study support the hypothesis that stress susceptibility is a cost of reproduction.

Outcomes associated with supportive periodontal therapy in smokers and nonsmokers.

PURPOSE: This study evaluated the effects of smoking status on retrospective clinical and radiographic measures of periodontal disease and compared these to prospective changes in digital radiographic bone height. METHODS: Clinical data on moderate (4 to 6 mm) and severe (> 6 mm) periodontal pocket depths, and bleeding on probing, were obtained from 95 subjects on suggested three-month supportive periodontal therapy (SPT) for AAP Class III/IV periodontitis. Standardized radiographic data were obtained concerning posterior interproximal alveolar bone height from 36 of the 95 subjects using computer-assisted digital technology at baseline and one year later. The subjects were divided into groups by smoking status: current, former, and never. Data were evaluated using a general linear statistical model. RESULTS: Evaluation of clinical data showed that current smokers exhibited a significantly higher percentage of moderate (18%) and severe (1%) periodontal pockets than nonsmokers (10% and 0%, respectively; p < 0.002). Baseline radiographic interproximal bone height loss also was greater in current smokers (5.75 +/- 1.07 v. 4.64 +/- 1.16 mm). Bone loss over one year occurred in 5% of the sites, but was not significantly different among groups. CONCLUSION: Clinical periodontal pockets and bone loss accumulated more rapidly in smokers, even though they submitted to regular supportive periodontal therapy. Although this population was clinically compliant over a one year period, digital radiography showed a high incidence of detectable bone loss. The impact of smoking, however, may require longer than one year to show longitudinal changes. It is recommended that a periodic radiographic analysis on bone height be considered during SPT, and longer term studies be conducted in order to accurately identify the outcome of smoking status on this variable.

Masticatory muscle activity assessment and reliability of a portable electromyographic instrument.

STATEMENT OF PROBLEM: Masticatory muscle hyperactivity is thought to produce muscle pain and tension headaches and can cause excessive wear or breakage of restorative dental materials used in the treatment of prosthodontic patients. The quantification and identification of this type of activity is an important consideration in the preoperative diagnosis and treatment planning phase of prosthodontic care. PURPOSE: This study investigated the quantification process in complete denture/overdenture patients with natural mandibular tooth abutments and explored the reliability of instrumentation used to assess this parafunctional activity. MATERIAL AND METHODS: The nocturnal EMG activity in asymptomatic complete denture/overdenture subjects was assessed with and without prostheses worn during sleep. Because of the large variance within and between subjects, the investigators evaluated the reliability of the 3 instruments used to test nocturnal EMG activity in the sample. RESULTS: Electromyographic activity data of denture/overdenture subjects revealed no differences between prostheses worn versus not worn during sleep but demonstrated a very large variance factor. Further investigation of the instrumentation demonstrated a consistent in vitro as well as in vivo reliability in controlled laboratory studies. CONCLUSION: The portable EMG instrumentation used in this study revealed a large, uncontrollable variance factor within and between subjects that greatly complicated the diagnosis of parafunctional activity in prosthodontic patients.

Comparison of methods for measuring root and mucogingival sensitivity.

OBJECTIVE: The aim of this study was to compare the variability of measurements of root and mucogingival sensitivity over a 24-hour period. STUDY DESIGN: Sixteen individuals (46.8 +/- 3.2 years old) were randomly tested for pain thresholds with calibrated electrical stimulation of the root and adjacent mucosa (electric pulp tester), pressure on mucosa (pressure-sensitive probe), and cold on the root (experimental thermocoupler probe) at baseline and after 4, 8, and 24 hours. Variability between and within subjects was estimated by using analysis of variance for random effects. RESULTS: Intrasubject variability was highest for electric testing of the root and lowest for cold testing of the root across time. Of all subjects, 93% fell within 5 degrees C at all periods for the cold stimulation/moderate pain threshold. CONCLUSIONS: Calibrated cold stimulation of root areas appears to provide the most sensitive measure to assess therapeutic interventions to control cervical dental pain because of low intrasubject variability in untreated patients.

Management of patients needing antibiotic prophylaxis in a dental education setting.

The management of antibiotic prophylaxed (ABX) patients at an educational institution was evaluated to identify areas for improvement. Management criteria, reflecting guidelines to prevent oral-induced hematogenous microbial seeding, were pretested and applied to 1,225 record entries of eighty-five patients needing ABX for dental treatment between 1991 and 1996. Seven hundred twenty-two of the visits had 857 management or documentation problems, including no documentation indicating whether or not patients premedicated (n = 281); incomplete, insufficient, or repeated treatment (n = 214); and preventive concerns (n = 172), among others. The proportion of providers' patient visits with one or more management problems differed significantly (p < 0.001) by provider type, as did the distribution of problem categories (documentation, treatment, preventive, and scheduling concerns p < 0.001; compliance issues p < 0.005). Fifty-one percent of postgraduates' and 39 percent of faculty's record entries omitted patients' ABX status. Improved documentation, outcome measures, and patient, faculty and student education are indicated.

Pharmacokinetics of bisphenol A released from a dental sealant.

BACKGROUND: Limited information is available regarding potentially estrogenic bisphenol A, or BPA, released from dental sealants. This study determined the rate- and time-course of BPA released from a dental sealant (Delton Opaque Light-cure Pit and Fissure Sealant, Preventive Care/Dentsply) when applied at a dosage of 8 milligrams (one tooth) or 32 mg (8 mg on each of four teeth) to 40 healthy adults. METHODS: The authors recruited 40 healthy subjects (18 men and 22 women, 20-55 years of age) who did not have histories of pit and fissure sealant placement or composite resin restorations. The authors collected saliva (30 milliliters) and blood (7 mL) specimens from all subjects immediately before sealant placement (baseline) and at one hour, three hours, one day, three days and five days after sealant placement. They used high-pressure liquid chromatography to determine BPA (detection sensitivity 5 parts per billion, or ppb) in all specimens. RESULTS: The authors detected BPA in some saliva specimens (5.8-105.6 ppb) collected at one hour and three hours. The BPA, however, was not detectable beyond three hours or in any of the serum specimens. For the one- and three-hour saliva samples, the BPA concentration in the high-dose (32 mg) group was significantly greater than in the low-dose (8 mg) group (P < .05, Wilcoxon signed rank test). In the high-dose group, there was a significant decrease in saliva BPA concentrations from one hour to three hours (P < .01, Wilcoxon signed rank test). CONCLUSION: This study showed that BPA released orally from a dental sealant may not be absorbed or may be present in nondetectable amounts in systemic circulation. The concern about potential estrogenicity of sealant may be unfounded.