Shoulder complaints after nerve sparing neck dissections

The purpose of the study was to analyse the prevalence of shoulder complaints after nerve sparing neck dissection at least 1 year after surgery, and to analyse the influence of radiation therapy on shoulder complaints. Patients were interviewed for shoulder complaints, and patients filled out the shoulder disability questionnaire to evaluate shoulder disability in daily activities. In total 137 patients; 51 after modified radical neck dissection (MRND), 21 after postero-lateral neck dissection (PLND), and 65 after supraomohyoid neck dissection (SOHND) were analysed. After MRND 33.3% of the patients experienced shoulder complaints, after PLND 66.7%, and after SOHND 20% of the patients experienced shoulder complaints. Type of neck dissection was significantly (P < 0.001) related to shoulder complaints. Outcome on the shoulder disability questionnaire also showed a significant (P < 0.01) difference in outcome for type of neck dissection. The prevalence of shoulder complaints after SOHND are low, and reduce disability in daily activities. Radiation therapy does not have a significant effect on shoulder complaints and disability.     

The effect of calcium fluoride (CaF(2)) on the chemical solubility of an apatite-mullite glass-ceramic material.

OBJECTIVE: To assess the effect of varying CaF(2) on the chemical solubility of apatite-mullite glass-ceramic (G-C) materials in both the glassy and crystallized states. METHODS: Apatite-mullite forming glasses used in this study are ionomer cement derivatives based on the general formula (4.5SiO(2)-3Al(2)O(3)-1.5P(2)O(5)-3CaO-XCaF(2)). Six glass formulations were produced where X=0.5, 1, 1.5, 2, 2.5 and 3, and called HG1-6, respectively. Batches were melted in covered silliminite crucibles in a furnace overnight at 1050 degrees C, then at 1450 degrees C for 2h, before quenching in water. The six glass compositions were analyzed using differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF). Thirty discs (2mm thick and 12 mm diameter) were produced per glass using the lost wax casting technique. Ten were left as cast and 10 heat treated to either apatite or apatite-mullite. Solubility testing was carried out according to International Standard BS EN ISO 6872 1999 and the mass difference in solubility calculated as mug/cm(2). A lithium disilicate G-C system was used as a control material. RESULTS: All compositions formed glasses and on heat treatment could form apatite and apatite-mullite. The as-cast glass samples were the most soluble followed by the apatite samples. The apatite-mullite G-C was significantly less soluble than the other two phases (p<0.05) for all six compositions. The control material was significantly less soluble than all the HG glass-ceramic compositions for every phase (p<0.05). Decreasing the CaF(2) content (3-0.5 mol%) led to a decrease in solubility, without affecting the ability of the material to form apatite and apatite-mullite phases. SIGNIFICANCE: Increasing the CaF(2) content increases the chemical solubility for the glass, apatite G-C and apatite-mullite G-C phases. The solubility values obtained show that all the compositions, as cast and heat treated would be suitable for use as core ceramics.     

NO-cGMP signaling molecules in cells of the rat molar dentin-pulp complex

By the formation of cyclic guanosine 3',5'-monophosphate (cGMP), nitric oxide (NO)-sensitive enzyme-soluble guanylate cyclase (sGC) plays a receptor role for NO within the NO-cGMP signaling cascade, which is involved in vasodilatation and neurotransmission. The hypothesis that NO-cGMP signaling molecules modulate cells of the dentin-pulp complex was investigated in rat molars by histochemical, immunohistochemical, immuno-ultrastructural, and organ bath techniques. NO synthase (NOS) I-III, the sGC alpha(2)-subunit/beta(1)-subunit, and cGMP were detected in odontoblasts and blood vessels. NOS I, sGC alpha(2), and cGMP were identified in nerve fibers. Treatment of rat molars with the NO donor NONOate (10(-5) M) increased cGMP staining intensities in blood vessels and odontoblasts, while NO synthase inhibitor L-NAME (10(-4) M) attenuated intensity of the reaction products for cGMP, suggesting an effect of endogenous NO on sGC. These correlations of patterns and alterations of cGMP staining intensities after treatment with the NO donor or NO inhibitor might represent an NO-sGC-cGMP signaling-dependent modulation of odontoblasts, blood vessels, and nerve fibers in the dentin-pulp complex.     

Cementum and dentin in hypophosphatasia

Hypophosphatasia (HPP) often leads to premature loss of deciduous teeth, due to disturbed cementum formation. We addressed the question to what extent cementum and dentin are similarly affected. To this end, we compared teeth from children with HPP with those from matched controls and analyzed them microscopically and chemically. It was observed that both acellular and cellular cementum formation was affected. For dentin, however, no differences in mineral content were recorded. To explain the dissimilar effects on cementum and dentin in HPP, we assessed pyrophosphate (an inhibitor of mineralization) and the expression/activity of enzymes related to pyrophosphate metabolism in both the periodontal ligament and the pulp of normal teeth. Expression of nucleotide pyrophosphatase phosphodiesterase 1 (NPP1) in pulp proved to be significantly lower than in the periodontal ligament. Also, the activity of NPP1 was less in pulp, as was the concentration of pyrophosphate. Our findings suggest that mineralization of dentin is less likely to be under the influence of the inhibitory action of pyrophosphate than mineralization of cementum.     

Plunging or cervical ranula. Review of the literature and report of 4 cases.

A review of the literature pertaining to plunging ranula is presented with special emphasis on the historical development of the various aetiological theories and treatment recommendations. Also 4 cases of plunging ranula are presented; three were treated by extirpation of the sublingual gland and one was treated by exteriorization of the ranula into the oral cavity. The treatment methods used here are discussed in relationship to the accepted aetiological theory.     

Effect of reducing frequency of augmented feedback on manual dexterity training and its retention

OBJECTIVE: The study addressed the impact of the frequency of tutorial-enriched augmented visual feedback, provided by a virtual simulation system (DentSim), on the skill acquisition for a cavity preparation task in novice dental students. METHODS: Thirty-six subjects were assigned to two training groups and a control group. The task consisted of a geometrical cross preparation on the lower left first molar. All subjects performed a pre-test to assess their basic skill level. The training groups received simulation feedback, enriched with tutorial information, across acquisition. One group trained under continuous augmented feedback, while a second group trained under an intermittent (66% of the time) feedback. At both 1-day and 4-month interval, subjects performed a retention test to explore learning specific effects. Two transfer tests were added to assess the extrapolation of the learned skills to an adjacent molar. All tests were performed in the absence of feedback. A control group performed all the tests, without preceding training. All preparations were graded by the simulation system. RESULTS: The training groups performed similarly across acquisition and improved with practice (ANOVA, P<0.001). After 1 day and 4 months of no practice, the training groups outperformed the control group on a retention test (ANOVA, P<0.001) and transfer test (ANOVA, P<0.001). CONCLUSIONS: Performance and learning of a cavity preparation task on a simulation unit was independent of the frequency of tutorial-enriched augmented visual feedback within the range tested. Training sessions on a simulation unit could be alternated with training sessions in the traditional phantom head laboratory.