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Biomedical subjects

F J Roeters

Publications and source records attributed to F J Roeters.

34 records · Page 2Linked to original sources
PubMed1995

Treatment times for three different types of veneer restorations.

In a longitudinal clinical trial the treatment times needed for the fabrication of veneer restorations (VRs) were recorded and analysed. Treatment times were determined for: (1) direct resin composite (DC), (2) indirect resin composite (IC) and (3) porcelain (P) veneer restorations and for two preparation designs, with and without incisal coverage. Significant effects on the treatment times were found for the factors: (1) type of VR, (2) operator, (3) number of VRs and (4) 'problems' in try-in phase for indirect VRs (IC- and P-VRs). The mean total time needed to perform one DC-VR was 46 min with a 95% confidence interval (c.i.) of 40-54 min, for one IC-VR 70 min (c.i. 60-82 min) and for one P-VR 62 min (c.i. 53-71 min). In the cases where more than one VRs were placed in one patient the times per VR were respectively: DC, 38 min (c.i. 34-44 min); IC, 59 min (c.i. 52-67 min); P, 49 min (c.i. 44-55 min). The results of this study are considered to be useful in further cost-benefit analyses.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1995

Lactobacilli, mutants streptococci and dental caries: a longitudinal study in 2-year-old children up to the age of 5 years.

A 3-year cohort study was carried out in 252 pre-school children for early identification of caries-active individuals. During this period information was collected about the acquisition of mutants streptococci and lactobacilli from the age of 2 till 5 years old. At baseline mutants streptococci were detected in 43% of the children while the detection frequency of lactobacilli was low (11.5%). On an individual level, numbers of colony-forming units of mutans streptococci and lactobacilli in plaque and saliva varied largely during the study period. The correlations between the numbers of lactobacilli and mutants streptococci in the saliva of the mother and the saliva and plaque of the child were low and never exceeded r = 0.22. Very low correlations (< r = 0.22) were also found between the numbers of mutans streptococci or lactobacilli and the diet in terms of the number of sugar intakes. Nevertheless, in children older than 2.5 years correlations between the clinical caries score and lactobacilli in saliva (range 0.31-0.62) and mutans streptococci in plaque or saliva (range 0.24-0.46) were highly significant (p < 0.01).

Child, Preschool↗
PubMed1994

Prediction of the need for bitewing radiography in detecting caries in the primary dentition.

In recent literature some controversy has been reported regarding the prescription of bitewing radiography for caries diagnosis, particularly in children. While the low prevalence of caries justified the decision not to take radiographs, it has also been reported that the benefits of detecting slowly progressing, clinically undetectable lesions could outweigh the "costs" of radiography. It was the aim of this study to investigate whether specific risk factors could predict the presence of additional dentinal lesions (ADL) in the primary dentition on radiographs which could not be detected by visual inspection. Bitewing radiographs were taken in 182 children aged 5 yr. Risk factors for ADL were identified and appropriate rating scales were designed. Sensitivities, specificities and relative risks expressing the relation between scale values and ADL were computed for each of the risk factors and direct and stepwise discriminant analyses were performed. The results indicate that particularly the presence of lactobacilli and mutans streptococci in saliva and the detection of three or more discolored enamel lesions or dentinal lesions were good predictors of ADL. It is suggested that these risk factors be used in the timing of bitewing radiography in children with a primary dentition.

Child, Preschool↗
PubMed1992

[Composite or amalgam? Not a black or white decision].

Amalgam as a restorative material in dentistry is discussed because of believed toxic properties of the material, yet there is no scientific prove for the assumption. Adhesive restorations are a possible alternative for amalgam in restoring posterior teeth. For treatment of primary caries, the direct composite resin restoration has many advantages. When greater defects are to be restored, adhesive composite resin restorations become less favourable. At this moment no long term results are available for indirect adhesive techniques. For the time being it seems necessary to use composite resin as well as amalgam for the restoration of posterior teeth.

Adhesives↗
PubMed1991

Aesthetic properties of three type II glass polyalkenoate (ionomer) cements.

The aesthetic properties of three recently marketed Type II glass polyalkenoate (ionomer) cements were evaluated in a combined laboratory and clinical study. The materials investigated were Fuji Cap II, ChemFil II in capsules and Ketac-fil Aplicap. The aesthetic properties of a glass ionomer restoration were represented by its translucency, the colour match with surrounding enamel and marginal adaptation. The translucency of all shades of the selected glass ionomer cements was measured under laboratory conditions and expressed as the optical density on transillumination. Colour match and marginal adaptation were evaluated in a clinical study. Twenty Class V restorations of each of the three products were placed. After finishing, the marginal adaptation was rated by two clinicians and colour slides of the restoration were made. Five clinicians assessed the colour match of the restorations from colour slides. ChemFil II and Ketac-fil Aplicap shades were considerably more translucent than the Fuji Cap II shades. The colour match of the ChemFil II restorations was significantly better than the Fuji Cap II and Ketac-fil Aplicap restorations. Marginal adaptation was judged excellent for all three products.

Aluminum Silicates↗
PubMed1991

[Shape and/or colour anomalies of anterior teeth].

Many esthetically unpleasant positions of teeth can be improved by orthodontic treatment but can also be camouflaged by built-ups with composite resins in combination with grinding of enamel. With this method orthodontic results can also be improved and relapses corrected. The technique and different possibilities are described and demonstrated with clinical examples.

Adolescent↗
PubMed1991

[Guidelines for treatment of missing anterior teeth].

The orthodontic treatment of patients with missing incisors should be directed to avoid prosthetic solutions. Specific rules have to be applied for the closure of spaces due to missing teeth to reduce the occurrence of papillae retraction and to place the substituting teeth in such a position that their crowns can be built up to look like the ones they replace. To realize these goals the mesiodistal angulations should deviate from the standard ones, a proper distribution of crown width should be achieved and finally a permanent retention with a palatally bonded thin multi-stranded wire should be installed in most cases.

Anodontia↗
PubMedDate not supplied

Loss of sound tooth structure when replacing amalgam restorations by adhesive inlays.

The replacement of amalgam restorations by adhesive inlays requires an adjustment to the cavity form. This often necessitates the removal of sound tooth substance. Undercuts may be blocked out by a base, but an extensive use of glass ionomer for this purpose is not recommended due to the weak mechanical properties of this material. The present study estimated the amount of sound tissue removed when a given amalgam preparation was reshaped for an adhesive inlay without the use of a base. An MOD amalgam preparation was created in an acrylic tooth. Twenty copies were distributed among 20 operators, who were requested to transform the preparation into an adhesive inlay preparation, removing as little material as possible. One control preparation with parallel walls was produced. All teeth were weighed before and after the alteration. The preparations' volumes were calculated: original amalgam preparation 0.130 ml, parallel preparation 0.136 ml. The minimum removal necessary was therefore 0.006 ml. The amount removed by the operators varied, with a mean volume of 0.0138 +/- 0.004 ml. Statistical analysis showed that for the given preparation, significantly more material was removed than necessary for undercut elimination. On average, more than twice the minimal volume of material was lost. This loss can be minimized by developing alternative techniques for undercut elimination.

Dental Amalgam↗