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Biomedical subjects

L V Powell

Publications and source records attributed to L V Powell.

At least 19 recordsLinked to original sources
PubMed2002

Assessment of periodontal conditions and systemic disease in older subjects. I. Focus on osteoporosis.

BACKGROUND: Osteoporosis (OPOR) is a common chronic disease, especially in older women. Patients are often unaware of the condition until they experience bone fractures. Studies have suggested that OPOR and periodontitis are associated diseases and exaggerated by cytokine activity. Panoramic radiography (PMX) allows studies of mandibular cortical index (MCI), which is potentially diagnostic for OPOR. AIMS: i). To study the prevalence of self-reported history of OPOR in an older, ethnically diverse population, ii). to assess the agreement between PMX/MCI findings and self-reported OPOR, and iii). to assess the likelihood of having both a self-reported history of OPOR and a diagnosis of periodontitis. MATERIALS AND METHODS: PMX and medical history were obtained from 1084 subjects aged 60-75 (mean age 67.6, SD +/- 4.7). Of the films, 90.3% were useful for analysis. PMXs were studied using MCI. The PMXs were used to grade subjects as not having periodontitis or with one of three grades of periodontitis severity. RESULTS: A positive MCI was found in 38.9% of the subjects, in contrast to 8.2% self-reported OPOR. The intraclass correlation between MCI and self-reported OPOR was 0.20 (P < 0.01). The likelihood of an association between OPOR and MCI was 2.6 (95%CI: 1.6, 4.1, P < 0.001). Subjects with self-reported OPOR and a positive MCI had worse periodontal conditions (P < 0.01). The Mantel-Haentzel odds ratio for OPOR and periodontitis was 1.8 (95%CI: 1.2, 2.5, P < 0.001). CONCLUSIONS: The prevalence of positive MCI was high and consistent with epidemiological studies, but only partly consistent with a self-reported history of osteoporosis with a higher prevalence of positive MCI in Chinese women. Horizontal alveolar bone loss is associated with both positive self-reported OPOR and MCI.

Aged↗
PubMed1998

Periodontal effects of a biobehavioral prevention program.

The present study tested preventive regimens in older subjects using dental services sporadically. 297 persons aged 60-90 (mean age 72.8; 43% ethnic minorities), were randomly assigned to either a control group or four interventions with incrementally more complex preventive strategies; behavioral training (group 2), added weekly chlorhexidine rinse (group 3), added semi-annual fluoride varnish (group 4), and added semi-annual prophylaxis (group 5). The control group received dental care as they preferred, primarily emergency care. All subjects were re-examined annually for 3 years. At baseline, 190 (64%) of the subjects were considered at risk for future periodontal disease progression. At baseline there were no group differences for any clinical parameter studied. Gingival bleeding varied between 19% and 23% over time and with no group differences. After 1 year, the greater decrease in probing depth for group 5 approached significance compared to the control group (p<0.06). Clinical attachment levels (CAL) improved in group 5 compared to the control group (p<0.01 for mesio-buccal, p<0.05 for mid-buccal tooth surfaces). The group differences did not persist at year 3. At year 3 in group 1, 9.2% and in group 5, 4.9% subjects lost > or =2.0 mm CAL. 310 teeth (6.5%) were extracted during the study period. A 21% increased risk for tooth loss was found in group 2, a 15% reduced risk in group 3, a 28% reduced risk in group 4, and a 44% reduced risk in group 5 compared to the control group (Wald-statistics robust p-value 0.12). At year 3, the tooth mortality rate in groups 3, 4 and 5 combined was reduced to 59% and significantly lower than groups 1 and 2 together (p<0.04). Self-efficacy was the best predictor of periodontal disease progression (F=7.02, p<0.01). Thus older persons benefited from a preventive oral health care program.

Age Factors↗
PubMed1998

Factors associated with caries incidence in an elderly population.

The purpose of this paper was to identify baseline factors associated with future caries development in older adults (age 60+) during a 3-year study period. Poisson regression analysis was used to determine the association between potential risk factors and disease incidence. The significant factors associated with high coronal caries incidence rates were high baseline root DMFS (P<0.001), high counts of mutans streptococci and lactobacilli (P=0.036), male gender (P=0.007), and Asian ethnicity (P=0.002). These factors had small to moderate effects on incidence rates, with relative risk values of approximately 1.2 to 2. The significant factors associated with higher disease incidence on root surfaces were baseline coronal DMFS (marginally significant, P=0.078), high bacterial counts (P=0.002), and Asian ethnicity (P=0.009). The predictive value of the models was low for both coronal and root caries. This result may be because this population had a higher than usual caries incidence rate, making discrimination among these caries-active individuals difficult. The current study affirmed the value of baseline DMFS and salivary variables to modeling caries incidence and introduced ethnicity as a variable useful for the study of dental caries in older adults.

Aged↗
PubMed1998

Caries prediction: a review of the literature.

For over a decade researchers have been looking for the formula that will allow caries prediction. The purpose of this summary is to review recent multifactorial prediction models for adults and children with the aim of identifying the most successful and consistent methods. Conclusions from this review include the following: Clinical variables, especially past caries experience, are confirmed as the most significant predictors of future caries development. The status of the most recently erupted/exposed surface is the most successful measure of past caries experience. Bacterial levels are included in the most accurate prediction models. Sociodemographic variables are most important to caries prediction models for young children and older adults.

Adolescent↗
PubMed1998

Caries risk assessment: relevance to the practitioner.

The dental literature is filled with recommendations for assessing the caries risk of patients. Some of these recommendations are based on sound research, some on clinical experience. This article attempts to explain the science of risk assessment.

Cariostatic Agents↗
PubMed1997

Evaluating the validity of probing attachment loss as a surrogate for tooth mortality in a clinical trial on the elderly.

Most periodontal trials are based on the assumption that the superior treatment, as judged by short-term intangible changes in probing attachment levels (the surrogate), is also the treatment most likely to affect tooth mortality. This assumption is valid if: (1) the surrogate is informative about tooth mortality, and (2) the surrogate captures a substantial proportion of the treatment effect on tooth mortality (e.g., > 50% or 75%). The goal of this study was to evaluate whether both conditions were satisfied in a randomized controlled trial (RCT) of elders at high risk for dental diseases. The results suggested that the first condition for a valid surrogate was satisfied: Both one- and two-year changes in probing attachment level were informative about tooth mortality risk. A 1-mm loss measured over a one-year period was associated with a 56% increased tooth mortality risk (relative risk = 1.56; 95% confidence interval, 1.08 to 2.26; p = 0.017); a 1-mm loss measured over a two-year period was associated with a 102% increased risk for tooth mortality (relative risk = 2.02; 95% confidence interval, 1.26 to 3.25; p = 0.004). The second condition necessary for a valid surrogate could not be confirmed in the present trial. With 95% confidence, it was concluded that one-year changes in probing attachment level measurements did not capture a significant proportion of the treatment effect (point estimate, 6%; 95% confidence interval;-38% to 53%). No useful statements could be made regarding the proportion of treatment effect captured by two-year changes, due to the width of the confidence interval (point estimate, 18%; 95% confidence interval;-151% to 140%). It is concluded that (1) the evidence surrounding the one-year change in probing attachment level indicates that it can be ruled out as being anything more than a weak surrogate marker for tooth mortality, and (2) further research is required to study the validity of two-year change in probing attachment level as a surrogate marker. Due to characteristics of the population and the treatments investigated, the generalizability of these findings to other RCTs is questionable.

Aged↗
PubMed1997

The effects of simple interventions on tooth mortality: findings in one trial and implications for future studies.

The purpose of this report was to use a particular clinical trial, the Preventive Geriatric Trial (PGT), as a starting point to discuss whether treatment efficacy can be evaluated by means of tooth mortality. In the PGT, 296 subjects were recruited and randomly assigned to five treatment groups: (1) usual procedures (UP); (2) UP + a cognitive-behavioral intervention (CB); (3) UP + CB + weekly chlorhexidine rinse (CHX); (4) UP + CB + CHX + semi-annual fluoride varnish (F); and (5) UP + CB + CHX + F + semi-annual prophylaxis, including scaling (P). Exploratory analyses revealed that tooth mortality after the 1st year was lower in treatment groups 3, 4, and 5 than in groups 1 and 2. A one-year exposure resulted in a 45% reduction in tooth mortality (p < 0.05); a two-year exposure resulted in a 59% reduction (p-value < 0.04). The PGT findings suggested that it is possible to design trials based on clinically relevant endpoints, such as tooth mortality. For the detection of moderate treatment effects, such trials could take the form of Large, Simple Trials (LST), where many subjects are recruited with minimally restrictive entry criteria, and data are collected only on essential baseline characteristics and tooth mortality. LSTs have provided "reliable answers to important clinical questions" for other chronic diseases, and several arguments suggest that they could play a similar critical role in dental research: (1) Periodontitis and caries are among the most common and costly chronic diseases affecting humans, and the identification of even moderately effective treatments by LSTs can have a large socio-economic impact; (2) the identification of low-cost widely practicable treatments that lend themselves to be investigated in LSTs is likely to benefit more people than the identification of high-cost complex treatments; and (3) tooth mortality is simple to assess and more relevant than the unvalidated surrogate endpoints that have largely failed for more than 20 years to provide reliable answers to certain controversial issues regarding treatment efficacy. The cost of not reliably establishing the safety and the efficacy of treatments may be far greater than the cost of conducting LSTs.

Aged↗
PubMed1992

Effect of admixed indium on properties of a dispersed-phase high-copper dental amalgam.

A new dental amalgam alloy containing admixed indium is available for clinical use. The purpose of this study was to conduct a full range of laboratory tests on two alloys containing differing amounts of admixed indium and on a similar alloy that did not contain indium. Results showed that less mercury was required to mix the alloys containing indium since admixed indium promotes wetting of the alloy. Back-scattered electron images showed the Ag-Hg matrix to be in good apposition to the Ag-Sn particles and to the Ag-Cu eutectic spheres, and there was no evidence of unreacted indium. The alloys containing admixed indium demonstrated improved resistance to creep and very little dimensional change upon setting. The early compressive strength was low for the alloys containing indium, but compressive strengths were significantly higher than those of the alloy without indium at 24 h and 7 d. Some improvement in resistance to marginal leakage and to corrosion was shown for the alloys containing indium.

American Dental Association↗
PubMed1992

Clinical performance of posterior composite resin restorations.

Two formulations of posterior composite resin (P-30 and Bisfil-P) were evaluated and compared to a high-copper, dispersed-phase amalgam (Dispersalloy). One hundred twenty-eight restorations were placed in 27 patients so that each patient received at least one of each material. After 3 years of clinical service, all three restorative materials produced clinically acceptable restorations, according to US Public Health Service and Leinfelder criteria. The amalgam restorations, however, underwent less wear (44 microns) than did the posterior composite resin restorations (60 to 74 microns). Stratification of data by type of tooth, class of restoration, and size of restoration produced the same ranking of wear from lowest to highest: Dispersalloy, Bisfil-P, and P-30. Resin restorations showed 45% more wear in molars than in premolars, and more wear was associated with moderately sized restorations than with conservative restorations. The surface texture of restorations of composite resin with porous strontium glass filler was nearly as smooth as that of enamel and was significantly smoother than that of the restorations of composite resin with zinc glass filler or of unpolished amalgam.

Analysis of Variance↗
PubMed1992

Clinical comparison of Class V resin composite and glass ionomer restorations.

Three techniques for restoring abrasion/erosion lesions were evaluated over a 2-year period: 1) glass ionomer restoration (Ketac-Fil); 2) composite restoration with a dentin bonding agent (Silux Plus, Scotchbond 2); 3) composite restoration with glass ionomer liner and a dentin bonding agent (Silux Plus, Vitrebond, Scotchbond 2). There were 116 lesions restored and 115 evaluated for color match, cavosurface discoloration, surface texture, caries development, and retention. Most restorations were rated clinically acceptable for color match, cavosurface discoloration, surface texture, and caries development when measured at 2 years. Glass ionomer restorations and composite restorations with a glass ionomer liner and a dentin bonding agent demonstrated better retention rates, 97.4% and 100% respectively, than the composite restorations with a dentin bonding agent only (86.8%) (Cochrane Q test, P = 0.07).

Aged↗
PubMed1992

Composite-resin materials and techniques in dentistry.

Important features to consider when selecting composite resins are filler size and amount, radiopacity, and fluoride content. Submicron particles provide the best polishability, and heavily filled resins demonstrate better wear resistance. The radiopacity of the composite resin should slightly exceed that of enamel to allow visualization of the restoration and recurrent decay. Fluoride added to the matrix may arrest the progression of caries. Properly cured composite resins should not cause chronic pulpal irritation; however, infection of the cervical contraction gap resulting from poor bonding to root surfaces may cause pulpal irritation. Techniques to improve curing include incremental build-up, reflective matrices and wedges, and controlling the direction of light vectors. A surface sealant is highly recommended to reduce wear, especially in the posterior region. Porcelain veneers perform better clinically than do composite-resin veneers. Class I and II composite-resin restorations reinforce weakened tooth structure; however, problems with cervical leakage and wear prevent the recommendation of these materials for larger posterior restorations that involve occlusal contacts or that require bonding to root surfaces.

Composite Resins↗
PubMed1992

Clinical evaluation of high-copper dental amalgams with and without admixed indium.

High-copper amalgam alloys containing 5% and 10% admixed indium, shown in previous studies to have improved properties and acceptable biological behavior, were evaluated in a clinical study designed to examine factors relating to clinical success. One hundred and seventy-five Class I and Class II amalgam restorations were placed in 25 patients. Each patient received all three dispersed-phase amalgams tested: without indium (Dispersalloy), with 5% indium (Indisperse 5), with 10% indium (Indisperse 10). After 30 months, 22 patients were recalled and 146 restorations evaluated. The margins of the indium-containing amalgam restorations incurred slightly less marginal breakdown, an effect that could be attributed to the addition of admixed indium and to the increase in silver-copper eutectic spheres which is found in these alloys. These amalgams also demonstrated a slightly darker appearance, and were slightly rougher than the non-indium-containing amalgam. These differences were minor; at 30 months, all restorations were well within the clinically acceptable range for each parameter evaluated.

Analysis of Variance↗
PubMed1991

Exploration of prediction models for caries risk assessment of the geriatric population.

The purpose of this study was to demonstrate a method for establishing a model designed to predict the caries risk of elderly individuals. Twenty-three patients over the age of 65 and living in a semi-independent retirement center were examined; several variables were collected and analyzed for their ability to predict the development of new carious lesions. The analysis was performed using logistic regression where the proportion of new decay was used as the dependent variable. The model for prediction of combined coronal and root caries included the variables flow rate, gender, and root caries index. The proposed method has the advantages of easily collected data, individualized criteria, and the ability to order patients as to the relative risk of developing decay.

Aged↗
PubMed1991

Tooth bleaching: its effect on oral tissues.

After investigating the literature, we suggest these guidelines for tooth bleaching: If bleaching solutions of high concentration are used, prevent accidental exposure of gingival tissues to the solutions by use of a rubber dam. If using lower concentrations of bleaching solutions, avoid long-term exposures to gingival tissues. To maintain pulp vitality, keep bleaching time and temperatures to a minimum. Check teeth for exposed dentin and enamel fractures. Advise patients that thermal sensitivity may occur after the bleaching procedure and may persist for several days. Prescribe premedication with an anti-inflammatory drug, when necessary. Avoid bleaching the cervical area of the tooth by covering the area with a base to avoid cervical resorption. Avoid dentin exposure by noting that abrasive bleaching techniques can remove significant amounts of enamel. Take special care when bleaching enamel--especially near the cervix of the tooth, where the enamel is thin.

Dental Enamel↗
PubMed1991

Clinical evaluation of direct esthetic restorations in cervical abrasion/erosion lesions: one-year results.

One hundred sixteen cervical abrasion/erosion lesions were restored with one of the following techniques: (1) glass-ionomer cement, (2) composite resin with a dentinal bonding agent, or (3) composite resin with a glass-ionomer cement liner and a dentinal bonding agent. The restorations were assessed at baseline and at 6 months and 1 year postrestoration for retention, caries, color match, marginal staining, and surface texture. No statistically significant differences were found in retention, caries, color match, or marginal staining. A statistically significant difference was found with regard to surface texture: glass-ionomer cement restorations demonstrated a rougher surface than did the composite resin restorations. A substantial number of restorations composed of composite resin with a dentinal bonding agent demonstrated a color shift towards mismatch when evaluated at 6 months. This difference was not significant at the 1-year followup.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1990

Sensitivity restored of Class V abrasion/erosion lesions.

The effectiveness of restorative treatment in reducing sensitivity associated with the Class V erosion/abrasion lesion was evaluated and the efficacy of three tooth-colored restorative materials in reducing sensitivity was compared. The 108 lesions were restored with either glass ionomer restorative material, composite resin with a dentin bonding agent, or composite resin with a dentin bonding agent and a glass ionomer liner. Composite resin with glass-ionomer liner restorations significantly reduced sensitivity to air and hot and cold water. Glass ionomer restorations and restorations with composite resin and a dentin bonding agent significantly reduced sensitivity but were also associated with increased sensitivity to air and cold respectively in 20% to 30% of the lesions restored when evaluated at 6 months.

Adhesives↗