Dr. Michael O'Sullivan

There are the principle Aims of the project: (1) Establishment of a National Database for patients with developmental dental anomalies. (2) Quality of life investigations for Adult Hypodontia and Amelogenesis Imperfecta patients. (3) Quality of life investigations for child and adolescent Hypodontia and Amelogenesis Imperfecta.

Abstract Aims. During extensive prosthodontic treatment the use of an accurately adjusted articulator is recommended to simulate some mandibular movements. This clinical study was undertaken to assess any possible effect of underlying skeletal pattern on programming articulator settings. Materials and Methods. Subjects were recruited (N=73) from a dental school and two regional specialist orthodontic units. Subjects were allocated into groups based on underlying sagittal and vertical skeletal patterns by a group consisting of three orthodontists and three prosthodontists who examined profile photographs. Electronic pantographic recordings were made of each subject with the Cadiax® Compact system to record the sagittal condylar inclination (SCI), progressive mandibular lateral translation (PMLT) and immediate mandibular lateral translation (IMLT). Results. Agreement between assessors for sagittal skeletal pattern classification was excellent (97% for total or good agreement). Agreement between individuals for vertical skeletal pattern was high, but at a lower level than for sagittal relationships (70% for total or good agreement). SCI settings for sagittal II subjects were significantly higher than those for sagittal I (p<0.05) and sagittal III (p<0.001) subjects. No statistical difference could be observed between the SCI values of the sagittal I and sagittal III groups. Subjects with an average vertical skeletal pattern had SCI values lower than those with a reduced vertical skeletal pattern (p=0.058) and significantly lower than subjects with an increased (p<0.01) vertical skeletal pattern. No patterns could be determined for PMLT or IMLT between the study groups. The PMLT measurements for all study groups clustered at the minimum value (5°) and to a lesser extent the maximum (15°). The majority of the sample population had IMLT settings of 0mm, with the remaining values ranging from 0.1 mm to 1mm. Conclusion. During prosthodontic treatment of patients with a noticeable skeletal discrepancy consideration should be given to customising SCI values.

Abstract Objectives: This study investigated the antibacterial efficacy and effect of 0.55% orthophthalaldehyde (Cidex OPA1) and 0.5% sodium hypochlorite (NaOCl) on the dimensional accuracy and surface quality of gypsum casts retrieved from an irreversible hydrocolloid impression material. Methods: A simulated clinical cast and technique was developed to compare the dimensional accuracy and surface quality changes of the test gypsum casts with controls. Dimensional accuracy measurements were completed between fixed points using a travelling microscope under low angle illumination at a magnification of X3. Surface quality changes of ''smooth'' and ''rough'' areas on the cast were evaluated by means of optical profilometry. The efficacy of the disinfection procedures against Pseudomonas aeruginosa was evaluated by determining the number of colony forming units (cfu) recovered after disinfection of alginate discs inoculated with 1 X 106 cfu for defined intervals. Results: The dimensional accuracy of the gypsum casts was not significantly affected by the disinfection protocols. Neither disinfectant solution nor immersion time had an effect on the surface roughness of the ''smooth'' area on the cast, however, a significant increase in surface roughness was observed with increasing immersion time for the ''rough'' surface. Complete elimination of viable Pseudomonas aeruginosa cells from alginate discs was obtained after 30 and 120 s immersion in Cidex OPA1 and NaOCl, respectively. Conclusions: Immersion of irreversible hydrocolloid impressions in Cidex OPA1 for 30 s was proved to be the most effective disinfection procedure.

SUMMARY This study was undertaken in a young Irish population to determine the dimensions and ratios of the six maxillary anterior teeth. One hundred and nine Irish subjects (age 18-25 inclusive) had irreversible hydrocolloid impressions made of their maxillary dentition poured in type V stone. Clinical crown dimensions were measured with a digital calliper. The stone casts were digitally photographed in a standardised manner enabling calculation of various ratios between the maxillary anterior teeth. Sexual dimorphism existed for various tooth dimensions; most notably canine teeth were in the region of 0.8 mm longer and 0.6 mm wider in males. Central and lateral incisors were found to be 0.5 mm wider in males. It is, therefore, recommended that dimensional tooth guidelines should be given for each of the sexes and not on a population basis. With regard to tooth proportion ratios, no significant differences were found between genders or the left and right sides for any of the measurements or ratios measured. The digitally recorded tooth proportions were similar for both sexes, and the Golden Proportion guidelines could only be applied to the lateral incisor ⁄ central incisor widths (0.618). Identified width proportions for the canine ⁄ central incisor were 0.58 and for canine ⁄ lateral incisor 0.89.