Volume 93 Number I

recommends a method whereby two sets of dental mod- els are mounted on semiadjustable articulators, one as a control and one as a working articulator. In the first stage, LeFort I model surgery is performed and its po- sition determined according to the cephalometric pre- diction tracing. An interocclusal wax bite is fabricated and later processed into an acrylic splint. The splint is used to fix the maxilla into the new predetermined po- sition by closing the intact mandible in hinge axis in- terior rotation. The second step is model surgery in the lower model, moving the mandible into Class I canine occlusal relationship. Overcorrection may be done at this stage.

The second interocclusal wax bite is fabricated with the same technique as the first wax bite and processed into acrylic splint. During the surgical procedure, the second splint is used to fix the maxilla and the mandible together in the predetermined final position and it re- mains in position through the whole period of fixation. With this jaw procedure, the surgeon will not lose the orientation during the fixation of simultaneous reposi- tioned jaw bones, thereby effecting a better result.

Alex Jacobson

Cephalometrics: A Comparison of 5 Analyses Currently Used in the Diagnosis of Dentofacial Deformities G. A. Wylie, L. C. Fish, and B. N. Epker lnt. J. Adult Orthodon. Orthognath. Surg. 1987;2:15-36

Various cephalometric analyses are used in the as- sessment of dentofacial deformities. The purpose of the article was to compare five such analyses as they relate to the

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following questions: Do the different cephalometric analyses gener- ally result in the same diagnosis? How well do these analyses relate to the actual orthognathic surgery performed? In the light of the answers to the aforementioned questions, what is the role of cephalometric anal- ysis in the different dentofacial deformities?

The writers compared five currently used analyses in ten persons with dentofacial deformities who under- went various surgical corrections. Pretreatment ceph- alometric radiographs of ten patients were specifically selected to illustrate ten different dentofacial deformi- ties, each of which was corrected by a different type of surgical procedure. The pretreatment cephalometric radiographs were assessed blindly by one investigator, who used the same criteria for each of the five analyses.

The results of these analyses (diagnoses) were then compared with one another and with the actual surgical

Reviews and abstracts 87

procedure that was performed; the comparison was made on a blind basis by a second investigator. When compared against one another with regard to specificity of the diagnosis for each patient, the analyses showed considerable inconsistency. Seldom did all analyses re- sult in the same diagnosis. When the diagnoses of the various analyses were then compared with the surgical procedures performed, no single analysis agreed with the actual surgical treatment performed more than 60% of the time. This information is consistent with the contention that cephalometrics cannot be considered as the primary diagnostic tool in the correction of dento- facial deformities.

Alex Jacobson

Bonded Resin Sealant for Smooth Surface Enamel Defects: New Concepts in “Microrestorative” Dentistry Theodore P. Croll Quintessence Int. 1987;18:5-10

Regardless of precautions taken and instructions to patients, orthodontists continue to be periodically plagued by areas of decalcification damage following removal of bonded brackets and/or bands. Because of this, orthodontists may be interested in knowing what can be done about the problem once it has occurred.

In a series of excellent color photographs, the article describes a method of using visible light polymerized resin bonded sealant to restore incipient carious lesions, areas of enamel decalcification, and enamel craze frac- tures on smooth dental surfaces. A technique combining resin sealant or resin dentin-enamel bonding agent with densely filled resin is also presented. Such blending is used when it is desirable to increase wear resistance of the smooth surface sealant or to mask an unsightly enamel defect in a cosmetically important region.

Alex Jacobson

Extraoral Small-Object Photography: The Easy Way to Good Results Gotz M. Losche Quintessence Int. 1987;18:135-7

The technique described is not intended to replace professional macrophotography, but offers an easy way to obtain good pictures of small objects at chairside with a normal clinical photography setup comprising a SLR camera with macrolens, flash unit (point-ring flash), and a surface-coated dental mirror.

The technique consists of focusing on the object,

88 Reviews and abstracts

which is held in front of the lens. Nothing should be seen in the viewfinder but the mirror surface.

On exposure the incident rays of the flash are re- flected twice.

1. The object surface reflects them into the lens. 2. The mirror surface reflects most. if not all, in-

cident rays into the room, where they disperse; only a small amount reaches the mirror again.

Thus, the rays reflected by the object lead to ex- posure of the film, rendering a picture of the object. Because the mirror reflects most of the light rays, the surrounding area remains black.

Alex Jacobson

Periodontal Status of Teeth Facing Extraction Sites Long-Term After Orthodontic Treatment Jon ktun and Stig K. Osterberg J. Periodontol. 1987;58:24-5

Orthodontic treatment of cases with arch length dis- crepancy often requires extraction of premolars. At the end of such treatment, a high frequency of incomplete space closure has been registered and tipping of the teeth adjacent to the extraction site has been observed. Conclusions differ regarding the association between open tooth contact and periodontal disease.

The study undertaken by the authors was to examine the long-term periodontal status of teeth orthodontically moved into extraction sites. Patients were examined 14

to 34 years after active orthodontic treatment mvolving extraction of four first premolars. Three groups were established: one with closed tooth contacts and parallel adjacent teeth, one with closed tooth contacts and tipped adjacent teeth, and one with open contacts between adjacent teeth. Within each group, comparisons were made of the following variables: accumulation of plaque, gingival health status, probing pocket depth, and probing attachment level of interproximal tooth sur- faces facing extraction sites and adjacent control sites between canine and lateral incisor.

Significantly more probing attachment loss was found in extraction sites with open tooth contacts (P < 0.01) and with parallel adjacent teeth and closed tooth contacts (P < 0.05) than in control sites. Fiow- ever, the mean differences were less than 0.5 mm, which may not be considered clinically significant. Tip- ping of teeth into the extraction sites had no long-term detrimental effect on the probing attachment level. No differences in accumulation of plaque and in gingival health status were observed.

The results of the investigation support other studies and indicate only small differences in periodontal break- down between extraction sites and other interproximai areas of long-term duration after orthodontic treatment. Complete space closure and paralleling of adjacent teeth do not seem to be of clinical significance for long-term periodontal disease in patients with good oral hygiene.

Alex Jucohson

AA0 MEETING CALENDAR 1988-New Orleans, La., May 1 to 4, New Orleans Convention Center 1989-Anaheim, Calif., May 14 to 17, Anaheim Convention Center 1990-Washington, D.C., May 6 to 9, Washington Convention Center 1991 -Seattle, Wash., May 12 to 15, Seattte Convention Center 1992-Q. Louis, MO., May 10 to 13, St. Louis Convention Center 1993-Toronto, Canada, May 16 to 19, Metropolitan Toronto Convention Center 1994-Orlando, Fla., May 1 to 4, Orange County Convention and Civic Center