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Biomedical subjects

B U Zachrisson

Publications and source records attributed to B U Zachrisson.

At least 19 recordsLinked to original sources
PubMed1991

Remodeling of canines to the shape of lateral incisors by grinding: a long-term clinical and radiographic evaluation.

A long-term clinical and radiographic follow-up study was performed after extensive remodeling of the permanent teeth of 26 adolescent patients. The canines were ground to the shape of lateral incisors as part of the orthodontic treatment, and the patients were recalled after 10 to 15 years for clinical examinations. Grinding had been performed either unilaterally or bilaterally on 37 teeth. Unground canines or adjacent teeth served as control or reference teeth. Standardized intraoral radiographs were taken with a paralleling technique. Enamel surface replicas produced by epoxy resin in silicone impressions of the ground teeth were studied by stereomicroscopy. The long-term results were favorable. No significant color differences were observed in 36 of the 37 ground canines. Only one tooth displayed a generalized yellowish discoloration, probably the result of extensive pulp obliteration. There were no significant differences between ground and unground teeth with regard to mobility, reaction to percussion, or temperature sensitivity. Electric pulp testing revealed no statistically significant differences between test and control teeth. Radiographic changes were evident in two of the 37 ground canines. One tooth showed marked obliteration of the crown pulp, and in another tooth the pulp obliteration was almost complete. In the remaining 35 teeth no apparent differences were noted between the ground and unground teeth. In the stereomicroscope two of the ground labial surfaces showed evidence of scratches and grooves produced by the diamond instrument after more than 10 years' observation, but in all other instances the ground surfaces were indistinguishable from normal adult enamel surfaces. In conclusion, the present study has demonstrated that extensive cuspal, labial, lingual, and interproximal recontouring by the grinding of young teeth associated with orthodontic treatment can be performed without discomfort to the patients and with only minor or no long-term clinical and radiographic reactions.

Child↗
PubMed1978

Clinical comparison of direct versus indirect bonding with different bracket types and adhesives.

A longitudinal clinical trial was made in forty-two children to compare some commonly used techniques for orthodontic bracket bonding. A particular study design (Figs. 1 and 5) allowed blind quadrantwise comparisons in the same patient of six different variables, including direct versus indirect bonding, adhesives of the filled diacrylate resin type with small versus large filler particles, and metal brackets with mesh-backed versus perforated bases. The same person bonded all brackets within one week and performed the orthodontic treatment by a friction-free edgewise light-wire technique. Efforts were made to minimize gingival irritation by using eccentrically placed brackets on small bases, by careful trimming of excess adhesives flash around the bases, and by directing much emphasis on oral hygiene measures. The plaque situation around the brackets and along the gingival margins and the gingival condition were assessed according to the criteria of the plaque and gingival index systems by a dental hygienist at each monthly visit during a test period of 6 months. The study demonstrated that both direct and indirect bonding with the different adhesives and bracket types could give clinically satisfactory results. Still, there were statistically significant differences in plaque retention, gingival inflammation, and bond strength. The bonding adhesive with small filler particles was more hygienic than and about as strong as two adhesives with larger, coarser filler particles. The mesh-backed brackets retained less plaque and gave stronger bonds than the brackets with perforated pads. Advantages of direct bonding over the indirect procedure were that (1) the bracket bases were fitted closer to the tooth surface (which improved bond strength), (2) it was easier to work clean and to remove excess adhesive flash around the bracket bases (to help prevent gingival inflammation and decalcification and facilitate debonding), and (3) the bonding adhesive constantly filled out the entire contact surface of the brackets (thus avoiding artificial undercuts and deficiency areas which are prone to promote decalcification). A number of other clinical observations were also discussed.

Acid Etching, Dental↗
PubMed1978

Improving orthodontic results in cases with maxillary incisors missing.

This article has aimed at providing information on how to improve clinical orthodontic results in cases in which maxillary central and lateral incisors are missing. Different sections deal with (1) treatment approach and mechanics, (2) details in finishing, (3) modifications of clinical tooth crowns by special procedures (grinding, composite "corners," gingivectomy), (4) functional considerations and root resorption, and (5) retention.

Bicuspid↗
PubMed1977

Clinical experience with direct-bonded orthodontic retainers.

The experience obtained in clinical evaluation of forty-three direct-bonded mandibular canine-to-canine retainers after a minimum observation period of 1 year (range, 1 to 2.5 years) is summarized. Results indicate that the bonded retainer has all the advantages of a fixed soldered retainer, in addition to being invisible. Patient acceptance was excellent, and the failure rate in terms of loose retainers was low. Also, for a number of other retention problems, direct bonding with different types of lingual wire seems to open up a range of promising new possibilities.

Adolescent↗