Puncture resistance and stiffness of nitrile and latex dental examination gloves

OBJECTIVE: The aim of the current study was to assess the puncture resistance and stiffness of nitrile and latex dental examination gloves. METHODS: Puncture resistance was measured by employing an adapted version of ASTM F1342-91 using both a 316 stainless steel puncture probe (0.8 mm diameter) and a dental injection needle (0.45 mm diameter) interfaced to a tensile testing apparatus. Glove specimens (12 cm length, 1.5 cm breadth) were removed for modulus (M100) evaluation by assessing the force required to elongate the specimen to 100% of the original length. Glove samples were also aged to investigate whether puncture resistance and M100 values varied with aging at 70 degrees C for 7 days in an air-circulating oven. RESULTS: The nitrile glove types were assessed to have significantly higher puncture resistance compared with the latex glove type when the steel puncture probe was the pentrometer when using the one way analysis of variance (ANOVA) at the 95% significance level. Interestingly the puncture resistance for the latex glove type was significantly higher (P < 0.001) when a dental injection needle was used as the pentrometer compared with the nitrile glove types. The M100 values were significantly higher for the nitrile glove types for which the stiffness increased when the gloves were aged (P < 0.001). CONCLUSIONS: The higher stiffness values resulted in increased puncture resistance when the nitrile glove specimens were aged irrespective of the pentrometer type. However, the ability of latex to re-seal itself on puncture may be beneficial when considering the protection potential of each glove type against breaches in cross infection. For clinicians that have experienced an adverse reaction to natural latex gloves, the results of the current study indicate that nitrile gloves are available at reasonable cost and offer the clinician comparable resistance to puncture with latex gloves.     

Safety and efficacy of a nightguard bleaching agent containing sodium fluoride and potassium nitrate.

OBJECTIVES: Transient sensitivity during bleaching is generally reported to affect 67% of patients. While most people tolerate this sensitivity, some find it impossible to continue treatment. The purpose of this study was to determine the safety and efficacy of an experimental, low-sensitivity bleaching agent. METHOD AND MATERIALS: Twenty-two participants bleached for a minimum of 6 hours per night over a 2-week period. The bleaching agent used, Experimental Product E, is a 10% carbamide peroxide gel containing potassium nitrate and sodium fluoride. Evaluations were performed at baseline and 1,2,13, and 26 weeks. Color change was measured using a value-ordered Vita classic shade guide and a colorimeter. Sensitivity of the teeth, gingiva, tongue, and/or throat was measured daily using a patient log. RESULTS: The median color change after 2 weeks was eight tabs. Approximately 36% reported sensitivity during the active whitening phase of the study. As a group, participants reported sensitivity during 13.7% of the total days spent whitening. CONCLUSION: Experimental Product E was shown to be safe. Participants experienced minor sensitivity during the active bleaching phase only. Experimental Product E was shown to be an effective bleaching agent for the subjects tested in this study.     

The power of children over adults when obtaining sweet snacks

Summary. Background. There is evidence to suggest that the family is becoming a more democratic unit and that children are spending more on sweet snack items than ever before. A study was thus undertaken to investigate the influence of children on parental decision‐making in relation to the use of sugary snacks. Methods. A cross sectional interview study; children aged 7–8 years from 20 inner‐city Manchester primary schools were asked about their sweet eating, their pocket money and their perceived levels of influence or autonomy within the household. The parents of these children were also asked to fill in a questionnaire that mirrored the children's questions. Results. There was a moderate but significant correlation between the opinion of the parents and that of the children on the extent of influence (Pearson coefficient r = 0·25, P = 0·001). When the adults (n = 181) were split into age groups, ≤ 29 years (n = 33), 30–35 years (n = 61) and ≥ 36 years (n = 87), the study showed that the older the adult, the less the child seemed to get his or her own way. Spearman's rho = 0·16, P = 0·03 (children's view) and rho = 0·17, P = 0·02 (adult's view). The dominant factors were related to money in the children's opinion, although the adults’ data suggested that older mothers (≥ 36 years) may be trying to limit their children's access to sweet snacks. Conclusions. Adults’ efforts to limit their children's intake of sweet snacks and drinks are being undermined by earlier and earlier influences in the child's life and by access to money, which allows the child to out‐manoeuvre his or her parents. This is compounded by the provision of additional income, mostly from grandparents.     

Prevalence and distribution of attached cementicles on human root surfaces

A study was undertaken to determine the prevalence and distribution of attached cementicles on different root surfaces of 415 extracted human incisors, canines, premolars and molars. The teeth were boiled in water and soaked in a 5.25% solution of sodium hypochlorite to clean the root surfaces of any soft tissue and debris. Examination with a dissecting microscope showed cementicles on 144 (34%) of the teeth. Cementicles were seen on approximately 50% of the canines and molars and on fewer than 50% of the other teeth. On canines, cementicles were found most frequently in the middle and apical thirds of the roots. On molars, cementicles were found most frequently in furcations. A relationship was noted between the presence of enamel pearls in molar furcations and enamel projections from the cementoenamel junction. The findings suggest that cementicles occur in certain locations frequently enough to be of clinical importance.     

Prevalence of deep periodontal pockets in New Mexico adults aged 27 to 74 years

The purpose of this study was to describe the distribution of advanced periodontal destruction (pocket depth equal to or deeper than six mm) in continuous residents, aged 27 to 74 years, of Lordsburg and Deming, New Mexico. The distance from the free gingival margin to the base of the gingival crevice or pocket was measured on the facial and mesiofacial sides of six index teeth. The presence of supragingival calculus, subgingival calculus, and plaque, as well as gingival bleeding around the index teeth, also were evaluated. Of the 372 examinees, only 46 individuals (12.4 percent) had at least one deep pocket equal to or deeper than six mm on at least one site on the six index teeth. Age was significantly associated with prevalence of deep pockets, although about 80 percent of those aged 47 to 74 years did not have deep pockets. Of those with deep pockets, 89.1 percent had fewer than four tooth sites (out of 12) affected. The only significant risk factor of the presence of deep pockets, other than age, was the number of teeth with plaque accumulations. Age and the number of teeth with plaque explained only 10.5 percent of the variability in the prevalence of deep pocketing, suggesting that risk factors other than those included in this study may be important. The results of this study indicate that destructive periodontal disease occurs at selected sites within the mouth, and that about 87 percent of the adults over age 27, in this population, do not have deep pockets in the six index teeth examined.     

Development of dental Pd-Ti alloys

Alloys, in which the main constituents are palladium and titanium, have the following potential advantages for dental application: corrosion resistance, biocompatibility and acceptable casting temperatures for porcelainfused-to-metal dental prostheses. Alloy compositions chosen for investigation were as follows: 30 w/o Ti which lies in the 5% single-phase region near TiPd, 50 w/o Ti which lies near the 1120°C melting temperature minimum of the Pd?Ti system, and 70% Ti which minimizes Pd content while still in a relatively low melting range (1300°C). Analysis of the X-ray diffraction of 70%Pd30%Ti showed mostly PdTi with some Pd₅Ti₃; in 50%Pd50%Ti mostly PdTi₂ was observed with some PdTi; in 30%Pd70%Ti mostly PdTi₂ was found with some alpha Ti and PdTi₄. The amounts of the minor phases in each of the 3 alloys depended on heat treatment. The Knoop hardness of the alloys ranged from 300–500 KHN for the as-melted condition; after heat treatment the maximum hardness values were 400 KHN. After centrifugal casting, hardness values increased to a range of 350 to 560 KHN, depending on composition. These values exceed those obtained for the pure metals which were in the neighborhood of 100 KHN. From anodic potentiodynamic scans the breakdown potentials in Ringer's solution for 70%Pd30%Ti, 50%Pd50%Ti and 30%Pd70%Ti were 600, 650 and 500 (SCE); the repassivation potentials for the same alloys are 450, 300 and 350 (SCE), respectively. These are all above oral potential. The Pd?Ti system investigated was, thus, found to have adequate corrosion resistance and hardness. Therefore, it can be considered of good potential as a dental prosthetic alloy.     

Inferior joint space arthrography and characteristics of condylar paths in internal derangements of the TMJ.

Inferior joint space arthrography and measurements of the condylar path provide scientific documentation of derangement of the TMJ disc and condyle. These derangements are described as an anterior displacement of the disk associated with posterior-superior displacement of the condyle when the teeth are closed into the intercuspal position. Clinical studies demonstrate that approximately 70% of a TMJ patient population present with some type or stage of these derangements. These observations have far-reaching implications regarding contemporary dental curriculum, particularly concerning exegesis of the MPD syndrome theory and concepts of dysfunctional dental occlusion.     

Taste acuity of the human palate. III. Studies with taste solutions on subjects in different age groups.

The taste acuity at the midline of the hard and soft palate near their junction and, for comparison, on representative areas of the tongue was determined in 80 subjects aged 11-79 years by applying test solutions of the four basic tastes. Twenty-one subjects (26%) could identify at least one taste on the hard palate but none could recognize all four tastes. Seventy subjects (87%) could identify at least one taste on the soft palate and 37 subjects (46%) could recognize all four tastes. Taste thresholds were much higher on the hard palate than on the tongue and were in most cases higher on the soft palate than on the tongue. The ability to recognize all four tastes was less frequent in older than in younger subjects and the difference was greatest on the soft palate and least at the foliate papillae. The differences were greatest for citric acid and least for sucrose. There was a tendency to lower thresholds for women compared to men for all four tastes on all areas examined which was most pronounced on the soft palate. No differences in taste thresholds were found between denture wearers and subjects with natural dentition. Smokers had higher thresholds than non-smokers only for salt on the soft palate and the base of the tongue.     

The effect of the operator on the clinical performance of amalgam.

In this study, the effect of the operator on the clinical performance of amalgam was examined by evaluating the marginal fracture characteristics of four alloys placed by four operators. The results were as follows: --Marginal fracture was influenced by the operator. Therefore, careful attention should be given to the cavity design and the placement technique. --The interaction between operators and alloys was such that, for the worst alloy, there was no difference caused by the operators; for the intermediate alloys, there were large differences caused by the operators; and for the best alloy (a non-gamma 2 system), there was almost no difference caused by the operators. --The difference in marginal fracture characteristics among alloys was greater than the difference attributed to operators. --It appears that all practitioners should use non-gamma 2 amalgams because such amalgams perform better clinically and are less susceptible to variations in operators.     

The surgical-orthodontic correction of mandibular deficiency. Part II

As discussed in Part I of this study, persons with mandibular deficiency and Class II malocclusions exhibit a wide spectrum of esthetic, cephalometric, and occlusal characteristics. In many such patients optimal overall results are best obtained via a combined orthodontic-surgical approach. In such patients a critical evaluation is essential to decide (1) the optimal operation and (2) the appropriate orthodontic-surgical sequencing. Our method of making these two basic decisions was presented in Part I. In this article the indications for mandibular advancement with or without genioplasty, total subapical mandibular advancement, superior repositioning of the maxilla, and inferior repositioning of the maxilla are discussed in detail. These alternatives are illustrated with representative cases, and the results are discussed. The intention of these two presentations is to illustrate an orthodontic-surgical approach to the correction of mandibular deficiency and Class II malocclusion that is predicated on a systematic evaluation of the individual patient rather than a standard approach.