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Correction to Volume 58, Issue 1, page 33.

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During 1989–90,473 parents of children being screened at an orthodontic graduate clinic completed a self-report form about the child's dental/facial appearance, reasons for seeking care and referral paths. Almost all (85%) of the 313 parents of children under the age of 16 years expressed concern about the appearance of the child's teeth, and 44% reported the child had been teased about this. Only 14% of the parents reported that it was the child who had first noticed the need for treatment. The rank order of reasons for seeking treatment were appearance of teeth (85%), advice of dentist (73%), and appearance of face (46%). Using logistic regression, overjet and malalignment were observed to be significant predictors of the parent-report of the child being teased (odds ratios, OR, 5.5 and 2.4, respectively). Overjet predicted citing facial appearance as the reason for seeking treatment (OR 2.9), while age predicted patient-referral (OR 2.2) and overjet predicted parental referral (OR 3.0). Increased overjet is an important focus for early treatment and might accordingly be expected to influence the value of early intervention.

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A novel video image processing technique was used to evaluate changes in the facial profile mimicking the effects of various orthognathic surgical techniques. Incremental changes were introduced in male and female images simulating the effects of mandibular advancement or set-back, maxillary advancement or set-back, and maxillary impaction. Twenty-two clinicians and 22 lay people completed questionnaires evaluating their level of sensitivity to changes in the facial profiles and their preferences regarding alternative profiles. The results indicate that in judging realistic color video images, both orthodontists and lay people are sensitive to relatively small horizontal changes in the facial profile. In contrast, orthodontists are less sensitive to relatively large vertical changes but more sensitive to horizontal mandiublar changes.

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The purpose of this investigation was threefold: 1) Determine if a person's smile improves with orthodontic treatment, 2) Determine if the amount of improvement varies among clinicians, and 3) Determine reasons for the variances. Results of this investigation were: 1) In all four categories of evaluation there was a definite improvement in the average scores from the pretreatment to the posttreatment evaluation. 2) The amount of improvement varied from orthodontist to orthodontist. 3) Some patients did not show improvement in one or more of the areas evaluated. 4) A profile photograph is not a reliable source of information to determine what a smile will look like. 5) To maximize the potential for improving a patient' s smile, we must consider moving maxillary anterior teeth vertically.

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Pressures from the tongue on the teeth were recorded in 21 children and adolescents before and after surgical reduction of the tongue. The recordings were made before surgery, and 6 and 12 months after the operation. Simultaneous measurements were made at the lingual surfaces of the maxillary and mandibular central incisors and at the left first molar, in the rest position and during chewing and swallowing. The method had been used in a previous study of normal cases, which served as a reference.

Presurgical pressures recorded in the rest position at the maxillary incisors agreed with measurements recorded in the same location in the reference sample. Measurements recorded during rest in the other locations were somewhat higher than those of the reference group. Pressures recorded before the surgery during chewing and swallowing varied from similar measurements made in the reference group. At the recording 6 months after surgery, resting pressures at the molars were lower than they had been presurgically. No significant differences were found for pressures during chewing. A lower pressure was recorded in one location during swallowing. At the recordings made 12 months after surgery none of the pressures differed significantly from the presurgical values. Resting pressures were, however, lower than they had been before surgery and were closer to those of the reference sample.

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The “Thomas” indirect technique for bracket attachment produces an interface not present in direct techniques, that is, an aged composite-sealant interface. Our primary goal was to determine if a weakened interface was produced by a modified (sealant was mixed prior to placement of brackets) Thomas indirect technique when the composite was aged for 7 days. The enamel-bracket system was investigated in vitro by comparison of shear bond strengths for metal and ceramic brackets bonded to bovine teeth by a direct and indirect method. Nearly all specimens failed at the bracket-composite interface and, subsequently, no difference was found between specimens placed by direct or indirect methods. No evidence was found to suggest that an aged composite would predispose the enamel-bracket system to fail at the sealant-composite interface. The ceramic brackets used in this investigation had lower bond strengths then metal ones, but the breaking loads were similar.

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A total of 600 metal mesh-backed brackets were directly bonded to the anterior teeth of randomly selected orthodontic patients. Prior to bonding, enamel etching was carried out with 37% phosphoric acid on one side and with 2% phosphoric acid on the other side. The etch duration was 30 seconds. After 1 year no statistically significant difference was found between the failure rates of the two etching procedures. The assessment of the Adhesive Remnant Index (ARI) after debonding, however, revealed that the application of 37% acid resulted in significantly higher amounts of residual adhesive left on the teeth. The present study demonstrates that a phosphoric acid concentration of 2% can be sufficient for bracket bonding on anterior teeth.

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The purpose of this study was to analyze the tensile bond strength and debonding failure mode in younger and older permanent teeth after etching for 15 and 60 seconds. Bond strength did not change significantly when etching time was increased from 15 to 60 seconds in younger or older permanent teeth. However, regardless of etching time, the bond strength of the older permanent teeth was greater than that of the younger teeth with statistically significant differences. Four types of debonding interface were found; bracket base-resin, within the resin, resin-enamel and enamel detachment. There were no statistically significant differences noted among younger and older permanent teeth with 15 or 60 second etching fracture mode incidence at debondings. Enamel detachment was found only at etching times of 60 seconds. To reduce enamel destruction and save chair time, 15 second etching on either younger or older permanent teeth is suggested.

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Forty-four brackets were bonded “in vivo” using cotton roll and rubber dam isolation. Maxillary and mandibular premolars, to be extracted for orthodontic reasons, were used in this study. After bonding, the teeth were retained in the mouth for at least 30 days. They were extracted using surgical elevators. After extraction, the teeth were secured in plastic rings using gypsum and kept in water for 7 days until debonding. A Universal Instron Machine was used to produce a shear force at a speed of 0.1 cm/min until each bracket was removed. No statistically significant differences for debonding strength were observed between the two types of isolation, nor between the buccal and palatal surfaces of the teeth. One hundred percent of the failures occurred at the bracket/composite interface.

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