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During tooth preparation, the air and water from a dental handpiece occasionally cause painful stimulation of hypersensitive teeth. Use of mouthguards may be an alternative for the management of patients with tooth hypersensitivity.
STATEMENT OF PROBLEM: The influence of different types of restorative design features on the long-term survival of Dicor glass-ceramic restorations is only partially understood. PURPOSE: This study examined the effect of different types of luting agents and preparation core structures on the survival of Dicor glass-ceramic restorations functioning in vivo. MATERIAL AND METHODS: A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. The survival of restorations of different types, with different luting agents and preparation core structures, was described with Kaplan-Meier survival functions. The significance of differences in survival between different tooth or tooth-substitute preparation core structures and different luting agents was determined with the log-rank test. RESULTS: The probability of survival of a typical acid-etched Dicor restoration luted to gold preparation core structures was 91% at 16 years compared with 75% for dentin preparation core structures (P<.01). The survival of acid-etched Dicor restorations luted to dentin preparations was significantly better than nonacid-etched restorations luted to dentin. Acid-etched Dicor restorations luted with resin composite exhibited a more favorable survival function than those luted with glass ionomer (P<.01) and zinc phosphate (P<.05). Differences between restorations luted with glass ionomer or zinc phosphate agents were not significant. CONCLUSION: Acid-etched Dicor restorations luted to gold preparation core structures exhibited significantly better intraoral survival than restorations luted to dentin. Acid-etched Dicor restorations survived better than nonacid-etched restorations when luted to dentin preparations. Acid-etched Dicor restorations luted with resin composite exhibited more favorable survivor functions than restorations luted with glass ionomer or zinc phosphate agents.
Differences in the tooth and tooth surface survival rates between four cohorts born in 1965, 1970, 1975, and 1980 were analysed in a historical cohort study including data on the permanent teeth of children aged 5-7 years at baseline and 19 years at the end of the study. A statistically significant reduction in caries occurrence in fissured surfaces in the three oldest cohorts was seen during the 3 years after the eruption of the teeth. Caries occurrence in the cohorts born in 1975 and 1980 did not differ from each other. The occurrence of caries in smooth surfaces was low in all age cohorts. Therefore, despite a systematic decrease in caries occurrence towards the younger cohorts, no significant differences were found between the cohorts in smooth surface decay. After the 3 first posteruptive years, practically no differences in survival rates between the cohorts were observed. In the two youngest cohorts, the figures during the 3 first years after eruption did not differ from the figures for the later years. Throughout the study, caries occurrence was symmetric and no gender differences were observed. No postponement of decay was found by the end of the follow-up time.
Although many studies have been made on the reinforcement of the bond between tooth and restorative resin, satisfactory results have not been obtained clinically. Attempts were made to obtain such a reinforced bonding using the aqueous solution of derivatives of amino acid, either N-methacryloyl alanine (MAL) or N-acryloyl alanine (AAL), and 2-hydroxyethyl methacrylate (HEMA). Following the treatment with these surfactants, a tensile bond strength of 103 kgf/cm2 (to enamel) and 80 kgf/cm2 (to dentin) was obtained by MAL-HEMA solution, and that of 99 kgf/cm2 (to enamel) and 58 kgf/cm2 (to dentin) in the case of AAL-HEMA solution. This is considered as the result of either the etching effect of the amino acid derivatives, effect of its reactive products with hydroxyapaptite or reaction between HEMA and an organic component of tooth structure, like a collagen.
Removable/functional appliance therapy can still be further expanded and developed. Retentive elements in the anterior region increase anchorage. Thereby, active forces can be utilised without anchorage loss. Functional appliances are indicated following extraction, to maximise on tooth migration. In first molar extraction cases, treatment with activators is relatively straightforward. When considering premolar extraction cases with possible need for extraction later of the third molars as well, then one should consider extraction of the first permanent molars. With correct use of the appliance, it is possible to optimally align the second molar teeth as well as favourably influencing the soft tissue profile.
Optimizing aesthetics in the anterior maxilla can be a challenge because of tissue contouring problems. Dental implants allow for restoration of edentulous areas, thus improving function. Some compromises may result as a result of the necessity of predicting the stability of the replacement restorations. The Frialit-2 dental implant system with the internal hex design provides excellent stability for single-tooth restorations. Aesthetics are maximized using Procera Allceram crowns. This case study describes in detail the following: diagnosing and treatment planning for a challenging trauma case; surgical preparation and placement of two Frialit-2 dental implants in the maxillary left central and lateral incisor areas; primary impression techniques and fabrication of a temporary prosthesis over ProTect abutments; second-phase opening; final impressions; and fabrication of two single crowns.
The DMF index distribution and the D, M, and F distributions on the whole teeth were described from a representative sample including 3,400 children at ages 6, 9 and 12. Results showed a great symetry for dental caries on each side of the median sagittal plane. The main spots of dental attack were found and the importance of each tooth in the determination of various indexes was analyzed. At each age, the first permanent molars are the most atracked. Many children have three or four decayed molars. Concerning the eruption of permanent teeth and the loss of primary teeth, we found the same symetry of these events between upper and lower maxillar as well as from on side of the median sagittal plane to the other.
Because bones and permanent teeth accumulate lead, exfoliated deciduous teeth have been utilized as retrospective markers of cumulative exposure in epidemiological surveys. In this paper we describe four models of lead uptake by the coronal dentin of shed primary teeth, each with different assumptions and ramifications. Each model is characterized by different relationships between blood lead at several ages and tooth lead. Values observed in our cohort of normal Boston children are most compatible with models positing the largest lead contribution coming at older ages (i.e., closer to age at exfoliation). Characteristics of models incompatible with our data include (1) lead deposition only during initial calcification and (2) no loss or resorption of lead.
This project, conducted by the Removable Prosthodontic faculty, compared the mesiodistal widths of the six maxillary anterior teeth with the widths of denture teeth from six different denture tooth manufacturers. Four hundred eighty-eight casts of dental students were measured from the distal aspect of each canine across the facial surfaces of the six anterior teeth with a flexible plastic millimeter rule. Denture teeth from six manufacturers were compared (370 molds). The results indicated that denture teeth are predominantly smaller and natural teeth are larger.
PURPOSE: This study measured the microtensile bond strengths of 2 tooth-colored restorative materials with and without conditioning of primary teeth dentin, and examined the micromorphology of the debonded surfaces and material-dentin interfaces. METHODS: Cylindrical specimens of packable composite resin (PCR) and resin-modified glass ionomer cement (RMGIC) bonded to dentin of primary teeth were ground to an hourglass shape and tested for microtensile bond strength. The debonded surfaces and material-dentin interfaces were prepared and examined under a scanning electron microscope (SEM). RESULTS: The microtensile bond strength values (mean +/- SD, in MPa) of PCR (Filtek P60 with Single Bond) and RMGIC (Fuji II LC), with or without the application of Cavity Conditioner (14.8 +/- 5.36, 12.01 +/- 4.43, 11.94 +/- 4.60, respectively), did not differ significantly (P > .05). Partial adhesive and partial cohesive failures within the restorative material predominated. The distributions of failure modes did not differ significantly between groups (P > .05). Under SEM, each material was seen to be closely adapted to dentin. Dentinal tubules were enlarged with etching, and the depth of penetration of resin tags of PCR was greater than for RMGIC. Smear plugs were incompletely removed by cavity conditioning. CONCLUSIONS: The bond strength of the PCR, Filtek P60 with Single Bond, to dentin of primary teeth was comparable to that of the RMGIC, Fuji II LC. Conditioning of the cavity preparation with Cavity Conditioner did not improve the bond strength of Fuji II LC. The distribution of failure modes did not differ between materials.
Since only relative results have been obtained with all in vitro investigations of tooth paste abrasiveness (i.e., dependent on the method of cleaning selected and the evaluation), an in vivo method was described with which absolute values may be obtained in the mouths of subjects participating in the cleaning tests.
A three step extraction procedure was carried out on intact hamster molar tooth germs in vitro labelled with 32PO4 and/or 3H-proline, in order to quantify separately the synthesis of dentine matrix (collagen) and the proline rich enamel matrix proteins. The extraction was based on the high solubility of the proline rich enamel matrix proteins compared with the relatively insoluble dentine matrix collagens. Pretreatment with 10% trichloroacetic acid (step 1) demineralized and removed the non-incorporated amino acids and/or small sized peptides. A consecutive water extraction (step 2) removed a large percentage of the phosphorylated amelogenins as assessed by SDS-urea-polyacrylamide-electrophoresis and amino acid analyses. Collagenase digestibility data showed that only small amounts of collagens were present in this extract. Further extraction with 10% formic acid (step 3) released only small amounts of amelogenins from the explants but also increased contamination with collagens and another predominantly low molecular components. Most of the 3H-activity remaining in the residues was found in the collagenase labile material and was considered to be an appropriate measure for production of dentine collagens. On the other hand, the residues also contained small amounts of 3H-labelled material with the same electrophoretic mobility as amelogenins but had much more 32P-activity than the amelogenins derived from the water and formic acid extracts. It is suggested that this material in the residues probably contains the crystal bound enamel matrix proteins.
The improvement in efficiency of prosthodontic therapy is linked to a strategic basic conception, the question of tooth preservation and extraction being of particular importance. The decisive criterion may consists in answering the question whether the step intended might contribute to structure preservation and function securing till old age or might be detrimental to these objective. The stomatologist may play a passive or an active role in the strategy of treatment.
Charcot-Marie-Tooth type 1A (CMT1A) disease and hereditary neuropathy with liability to pressure palsies (HNPP) are autosomal dominant neuropathies, associated, respectively, with duplications and deletions of the same 1.5-Mb region on 17p11.2-p12. These two rearrangements are the reciprocal products of an unequal meiotic crossover between the two chromosome 17 homologues, caused by the misalignment of the CMT1A repeat sequences (CMT1A-REPs), the homologous sequences flanking the 1.5-Mb CMT1A/HNPP monomer unit. In order to map recombination breakpoints within the CMT1A-REPs, a 12.9-kb restriction map was constructed from cloned EcoRI fragments of the proximal and distal CMT1A-REPs. Only 3 of the 17 tested restriction sites were present in the proximal CMT1A-REP but absent in the distal CMT1A-REP, indicating a high degree of homology between these sequences. The rearrangements were mapped in four regions of the CMT1A-REPs by analysis of 76 CMT1A index cases and 38 HNPP patients, who where unrelated. A hot spot of crossover breakpoints, located in a 3.2-kb region, accounted for three-quarters of the rearrangements, detected after EcoRI/SacI digestion, by the presence of 3.2-kb and 7.8-kb junction fragments in CMT1A and HNPP patients, respectively. These junction fragments, which can be detected on classical Southern blots, permit molecular diagnosis. Other rearrangements can also be detected by gene dosage on the same Southern blots.
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