Thomas Pioch

Enamel hypoplasia of primary teeth in chronic renal failure

Abstract Chronic renal failure (CRF) in the first years of life is associated with developmental defects of enamel in the permanent dentition. We investigated if CRF also affects the primary (deciduous) dentition. Thirty-one children with CRF on conservative treatment (n=12) or on renal replacement therapy (n=19) underwent dental inspection. In addition, 18 CRF children provided an exfoliated deciduous tooth for microscopic examination. Enamel defects were detected in a total of 12 children (31%), either clinically or microscopically. Of the 7 children affected clinically, 6 (19% of all examined) presented localized hypoplasia of the primary canines, which was found only in 3% of healthy control children: 1 patient had generalized pitted enamel hypoplasia. By microscopy, 5 of 10 primary canines examined showed enamel hypoplasia localized exclusively in enamel formed after birth. The ”birth line,” a visible structure within the primary enamel, was always present, which excludes a prenatal onset of the defects. Of the 12 patients with an enamel defect, 9 had a documented onset of CRF within the first 7 weeks of life. We conclude that renal disease leading to CRF may affect enamel formation of primary teeth in early postnatal life, resulting in lesions different from those observed in the secondary dentition.

Effect of cavity preparation instruments (oscillating or rotating) on the composite–dentin interface in primary teeth

OBJECTIVES To evaluate the effect of preparation of instruments on the interfacial integrity between cavity wall and composite restoration. METHODS Two class II slot preparations were done in 10 primary teeth either with SonicSys or with a conventional bur. The cavities were filled using an adhesive system. One layer of a flowable composite and one layer of a condensable composite were applied. The specimens were analyzed by confocal laser scanning microscopy. RESULTS In the SonicSys group the mean thickness of the hybrid layer was 6.12 (0.60) microm; in the control group it was 6.04 (0.63) microm. The difference was not statistically significant. Two fractures were observed in one tooth of each group. These were located only in the enamel. The cavity margins were beveled in all specimens. SIGNIFICANCE Compared to conventional preparations, cavity preparation with SonicSys has no deleterious effect on the integrity of the interface.

Preparation of dental hard tissue with picosecond laser pulses

The aim of this study was to investigate the suitability of picosecond lasers for hard-tissue preparation. Using scanning electron microscopy (SEM) and histological studies, the quality of ablation was examined. There was no thermal or mechanical damage observed. The ablation rates of enamel, dentine and carious enamel and the temperature rise during tissue removal were measured. Using a fast silicon photodiode, the lifetime of the plasma was determined to be 11±3 ns (Nd-YLF, 1.25 mJ pulse−1, pulse duration 30 ps). In order to achieve a better understanding of the ablation process, plasma parameters such as electron density [(5±3)×1017 cm−3] and excitation temperature (4500±2000 ℐg, Nd-YLF, 0.3 mJ pulse−1) were obtained from emission spectra. By examining the line width of singly ionized calcium lines, a difference was found in the ablation of healthy or artificially demineralized enamel, thus allowing the selective removal of caries.

Double-blind Study on Materials Testing with Applied Kinesiology

Applied Kinesiology (AK) is a scientifically unproven method used in complementary medicine to recognize the (in)tolerance of dental materials. Test-retest reliability of AK was examined. The working hypothesis was the assumption that the reliability of AK would not exceed random chance. Two dentists qualified in AK examined 112 volunteers to determine individual (in)tolerance toward two dental composite materials. After the first examination, 31 subjects were excluded from further testing. At the end of the open test phase, 34 of 81 participants had been classified as “tolerant”, and seven as “intolerant” to both materials. The remaining 40 individuals showed a combination of either tolerant (to material I)/intolerant (to material II), or the reverse (n = 20 each). Retrieval rate was tested under blind conditions. In 14 cases, the results of the open and blinded tests matched, whereas in 26 cases they did not (95% confidence interval, 21%-52%; p = 0.98). This outcome confirmed our working hypothesis.