Clinical significance of holes in gloves for dental use: a spectrophotometric analysis.

The aim of this study on latex dental gloves was to establish whether there is any relationship between faults that are detected by filling with water and the entry of liquid into the gloves during use. Twenty-four gloves of different sizes were examined. Large and small holes randomly distributed on the index, middle, and ring fingers, were made in the gloves. The gloves were filled with water and squeezed to detect the amount of water escaping. A mass spectrophotometer was used with the same gloves to quantify the entry of an aqueous solution of potassium bichromate during work. The filling method was effective for revealing all faults in gloves, but it was not able to determine whether there would be fluid entry through the holes during work. While the size of the holes was not predictive for the amount of liquid entering the glove, adherence of the glove to the hand was. Holes of the same size allowed a greater entry of contaminated liquid in adherent gloves than in looser ones.     

HIV parotid gland lymphoepithelial cysts. Review and case reports.

Lymphoepithelial cysts of the parotid gland are frequently associated with cervical lymphadenopathy. These unique cysts have recently been recognized as another manifestation of HIV disease. Proliferation of lymphocytes and salivary gland tissue contained within intra-parotid lymph nodes is observed. The lymphoepithelial cyst is the end product. Ultrasound imaging serves as an excellent technique to demonstrate the existence of these cysts.     

A study of bond strength between light- and self-cured orthodontic resin.

Light-cured orthodontic composite resin has been widely advertised recently for use in bonding. However, the curability of light-cured resin when light waves are diffused through metal, ceramic, or resin brackets is doubtful and questionable. This study evaluated the effectiveness of a visible light source in curing the resin under a solid metal bracket, compared the tensile bond strength at different exposures, and analyzed the broken interface distribution between light-cured resin with various light exposure times and self-cured resin. The bond strength results revealed that the difference between light-cured resin (Transbond) with 60, 40, and 20 seconds of light exposure, respectively, and self-cured resin (Concise) was 1.05, 0.92, 0.61, and 0.71 kg/mm2, respectively. The bond strength of Transbond with 60 and 40 seconds of light exposure was greater than both the bond strength of Transbond with 20 seconds of light exposure and the strength of the self-cured resin of Concise, with statistical significance (p less than 0.01). There were also no statistical differences between Transbond with 60 and 40 seconds of light exposure or Transbond with 20 seconds of light exposure and Concise. The bond failure interfaces were located between the bracket and the resin, within the resin itself, or between the resin and the enamel. Tooth fragmentation was rarely found. There were no statistical differences (p greater than 0.05) among broken interfaces. This indicates that visible light is powerful in curing the visible light-activated composite resin under solid metal brackets.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of tooth extraction on periodontal ligament mechanoreceptors represented in the mesencephalic nucleus of the cat

When a force is applied to a tooth, mechanoreceptors in the periodontal ligament are stimulated. When teeth are extracted the remnants of the periodontal ligament break down and disappear, but it is not known what happens to the mechanoreceptor neurones that innervated it. The present study seeks to determine the effect of tooth extraction on the population of periodontal ligament mechanoreceptor neurones represented in the mesencephalic nucleus of the fifth cranial nerve. The incisor and canine teeth were extracted from adult cats; terminal experiments were performed between 7.5 months and 2 yr later. Recordings were made in the mesencephalic nucleus with microelectrodes, and neurones were identified in the inferior alveolar nerve that previously innervated the periodontal ligament of one of the extracted mandibular teeth. The majority of these neurones responded only to electrical stimuli applied to the edentulous ridge of the mandible in the area where the incisor or canine teeth had previously been. It was not possible to stimulate them mechanically, despite the use of large forces. A small number had reinnervated new soft-tissue sites. They could be mechanically stimulated and were found adjacent to the area in which the mandibular incisor and canine teeth had been. Thus the population of periodontal ligament mechanoreceptor neurones represented in the mesencephalic nucleus do not all degenerate after tooth extraction. As the majority of those still present do not appear to reinnervate new tissues in which they can be mechanically stimulated, it is unlikely that they have any functional role after tooth loss.     

Effect of ultrasonic instrumentation on dental plaque microflora in vitro

The aim of the present study was to investigate in vitro the effects of an ultrasonic scaler on the composition of dental plaque and selected bacterial isolates. Plaque samples obtained from patients with periodontitis were submitted for 10 s, 20 s, 30 s and 60 s to ultrasonication. Bacterial suspensions were then examined by dark field microscopy and cultured on solid medium to evaluate bacterial growth. Dark field microscopic counts showed that percentages of spirochetes and motile rods decreased sharply after 10 s of sonication and could no longer be detected after 60 s. Conversely, a relative increase in the percentage of coccoid cells as well as others was observed. Cultures of plaque samples following ultrasonication demonstrated a marked increase in CFU between 0 and 10 s to reach a maximum at 30 s. When bacterial suspensions containing Treponema vincentii LA-1 and Streptococcus mutans OMZ 176 were submitted to ultrasonication, a net decline in the percentage of spirochetes and a concomitant increase in cocci were observed by dark field. After 30 s there were exclusively cocci in the suspensions and spirochetes were virtually undetectable. The effect of ultrasonication on spirochetes viability was also evaluated using pure cultures of T. vincentii LA-1 and T. denticola CD-1. The data indicated that 10 s or 30 s of sonication had an adverse effect on both species because no growth could be observed in these cultures. It can be concluded that vibrations generated by an ultrasonic scaler have the potential to alter the composition of dental plaque and to kill spirochetes in vitro.     

Filler systems based on calcium metaphosphates

Calcium metaphosphates (CMP's)--a unique class of phosphate minerals possessing polymeric structures, [Ca(PO3)2]n, and having refractive indices of approximately 1.54-1.59-- are optically compatible with resins such as BIS-GMA. In this study, several types of CMP's were prepared and evaluated for their potential as fillers for visible-light-activated (VLA) dental composites. The vitreous (V) and beta-crystalline forms of CMP were prepared by controlled thermolysis of monocalcium phosphate monohydrate, Ca(H2PO4)2.H2O. Hybrid fillers were also prepared by thermal methods. Fillers, characterized by IR spectroscopy and optical microscopy, were prepared in several size ranges (e.g., 1-100 microns). VLA composites were formulated by use of both untreated and surface modified CMP's. V-CMP and its hybrids yielded composites which expanded when stored in water but were of low strength, e.g., diametral tensile strength, (DTS) = 8 MPa. beta-CMP composites were more moisture-resistant, had higher DTS's (from 12 to 33 MPa), and showed a tendency to arrest brittle fracture. These novel fillers have potential uses in resin-based materials such as dental composites, cements, and adhesives.     

Periodontal disease in heterosexuals with acquired immunodeficiency syndrome

We studied the prevalence and severity of periodontal disease among 181 heterosexual men and women with AIDS. Included were 167 (92%) intravenous drug users (IVDU) and 14 sexual partners of persons at risk for AIDS. Periodontal disease was seen in 71 of 78 (91%) women compared to 75 of 103 (73%) men. Gingivitis was the most severe form of periodontal disease in 7 (9%) women and 15 (15%) men. Increased severity of periodontal disease was seen in women as compared with men (P less than .001); among subjects with periodontitis, 48 (75%) of 64 women had moderate to advanced disease compared to 32 (53%) of 60 men. For individuals with periodontitis, the extent of involvement was associated with severity; 90% of subjects with advanced periodontitis had all 4 quadrants affected. Concurrent oral manifestations of AIDS, including candidiasis, hairy leukoplakia, ulcers and Kaposi's sarcoma were present in 167 (92%) subjects. We conclude that HIV-associated gingivitis and HIV-associated periodontitis are common in heterosexual men and women with AIDS and are often accompanied by other oral manifestations of AIDS. The reason periodontal disease is more severe in women is not known. Clinicians should be aware that these disorders occur in heterosexuals as well as in homosexual men. Further study will be necessary to delineate the pathogenesis of these disorders.