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Correction to Volume 64, Issue 6, page 404.

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The purpose of this study was to examine the esthetic and periodontal differences between two methods of uncovering labially impacted maxillary anterior teeth: the apically positioned flap and closed-eruption techniques. The sample consisted of 30 patients who were recalled a minimum of three months after orthodontic treatment of a unilateral labially impacted maxillary anterior tooth. Eighteen of the patients had undergone an apically positioned flap (APF) procedure, and the remaining twelve had undergone the closed-eruption (CE) technique. In the CE group, clinical examination showed less width of attached gingiva on the distal surface and increased probing bone level on the facial surface of the uncovered teeth relative to their contralateral controls. Uncovered teeth in the APF group showed more apical gingival margins on the mesial and facial surfaces; greater crown length on the midfacial surface; increased probing attachment level on the facial surface; increased width of attached gingiva on the facial surface; increased probing bone level on mesial, facial, and distal surfaces; and gingival scarring. Radiographic examination showed shorter roots on the uncovered teeth in both groups. Photographic examination revealed vertical relapse of the uncovered teeth in the APF group. We conclude that labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more unesthetic sequalae than those uncovered with a closed-eruption technique.

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Flat rectangular tabs (n=84) prepared from lathe-cut amalgam (ANA 2000) were subjected to aluminum oxide sandblasting or roughening with a diamond bur. Mandibular incisor edgewise brackets were bonded to these tabs using: Concise (Bis-GMA resin); one of three metal-bonding adhesives, viz., Superbond C&B (4-META resin), Panavia Ex (10-MDP Bis-GMA resin) or Geristore (composite base); and Concise after application of the intermediate resins All-Bond 2 Primers A+B, or the Scotch-Bond Multi-Purpose (SBMP) system. All specimens were stored in water at 37° C for 24 hours before tensile bond strength testing. Alignment and uniform loading during testing were secured by engaging a hook in a circular ring soldered onto the bracket slot before bonding. Similar control brackets (n=12) were bonded with Concise to extracted caries-free mandibular incisors. Bond failure sites were classified by a modified ARI system.

Mean tensile bond strengths in the experimental group ranged from 3.4 to 6.4 MPa—significantly weaker than the control sample (13.2 MPa). Bond failure generally occurred at the amalgam/adhesive interface. Superbond C&B created the strongest bonds to amalgam; according to ANOVA and Duncan's Multiple-Range test, they were significantly stronger than the bonds with Panavia Ex and Concise, with Geristore in between. However, the bond strength of Concise to sandblasted amalgam was comparable to the Superbond C&B bonds when coupled with an intermediate application of All-Bond 2 Primers A+B. The SBMP, on the other hand, was less effective. Sandblasting was more effective in preparing the amalgam surface for bonding than roughening with a diamond bur, but the difference was not statistically significant. The clinical implications of these findings are discussed.

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The aims of this study were to determine if the palatal rugae are stable during normal growth, and whether treatment with either headgear or functional appliances affects the position of the rugae. Initial and 15-month recall dental casts of 94 patients enrolled in a study of early Class II treatment were evaluated. The children had been randomly assigned to one of three groups: control (n=34), headgear (n=30), and functional appliance (n=30). Landmarks on the palatal raphe and palatal rugae were recorded using the Reflex Metrograph. A median palatal plane was constructed using the digitized raphe points as reference. Offsets from this plane to the ruga points and transverse and anteroposterior linear distances between ruga points were obtained for all casts. Transverse offsets and linear distances between medial points of the first rugae and the anteroposterior distances between the medial points of the second and third rugae did not show statistically significant changes in all groups. Significant changes were observed for the lateral points of the rugae, particularly in the headgear group. The medial rugae appear to be suitable anatomic points for the construction of stable reference planes for longitudinal cast analysis.

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This study was undertaken to evaluate whether the majority of Class II skeletal patterns are mandibular retrusive or maxillary protrusive and also to compare four maxillary sagittal cephalometric indicators and four mandibular sagittal cephalometric indicators in a skeletal Class II sample. The Fishman SMA method was used to stratify the subjects into 11 maturity levels. Computerized cephalometric programs selected the subjects and compared the different indicators for each subject. The results indicate a wide diversity in the evaluation of maxillary protrusion and mandibular retrusion in these subjects. The Downs facial angle indicated that only 27.0% of the sample had mandibular retrusion. The angle NA-FH indicates that 56.3% of the sample had maxillary protrusion. These findings are in marked contrast to those evaluated by some of the other indicators.

Preliminary data from this study was presented at a combined meeting of the Orthodontic Society of the Cote D'Azur and the North Atlantic Component of the E.H. Angle Society of Orthodontists, Nice, France, October 1990 and at the annual meeting of the North Atlantic Component of the E.H. Angle Society of Orthodontists, Philadelphia, April 1991.

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Static frictional resistances were compared between Teflon-coated stainless steel and clear elastomeric ligatures used with various combinations of brackets and archwires. Stainless steel metal, polycrystalline ceramic and single crystal ceramic 0.022-inch slot brackets were used in combination with stainless steel and nickel titanium archwires, 0.01 8 inch and 0.01 6 ×0.022 inch. Friction was measured in the dry state at bracket-archwire angulations of 0, 5, 10, and 15 degrees. Moments induced by engagement of the archwires into the brackets were measured for each archwire type and bracket-archwire angulation. Teflon-coated ligatures produced less friction than elastomers for all bracket-archwire combinations. The ceramic brackets generally elicited greater frictional resistances than stainless steel brackets. Regarding both friction and control of tooth movement, these data suggest that sliding mechanics are best executed with stainless steel brackets and stainless steel archwires. Moreover, these data reveal the usefulness of Teflon-coated ligatures in minimizing the high friction of ceramic brackets when an esthetic appliance is imperative.

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Three fragments of the upper jaw of an Etruscan adolescent of the 6th century B.C. discovered at the necropolis of Cancellone 1 (Magliano in Tuscany, Grosseto, Italy) were examined. A triad of associated dental anomalies was found: congenitally missing second premolars, “peg-shaped” permanent lateral incisors, and ectopic (palatal) eruption of a permanent canine. These findings provided the opportunity to discuss etiopathogenetic aspects of the associations among different types of tooth abnormalities.

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