Nonsurgical rapid maxillary expansion in adults: report on 47 cases using the Haas expander.

Rapid maxillary expansion (RME) in the adult is thought to be an unreliable procedure with several adverse side effects and, consequently, surgically assisted RME is considered the preferred procedure. The purpose of this paper is to study the efficacy of nonsurgical RME, and to determine the incidence of complications such as relapse of the expansion, pain and tissue swelling, tipping of the molars, opening rotation of the mandible and gingival recession. Rapid maxillary expansion using a Haas expander was examined in 47 adults and 47 children. A control group of 52 adult orthodontic patients who did not require RME was also studied. Students' t-test, and the analysis of variance followed by the Scheffe test were used to determine if there were significant differences among time periods and among the 3 study groups. The mean transarch width increase was similar in adults and children who had RME; 4.6 +/- 2.8 compared to 5.7 +/- 2.4 mm for the molars and 5.5 +/- 2.4 compared to 5.7 +/- 2.5 mm for the second premolars. In the adults, transarch expansion and the correction of the posterior crossbites were stable following discontinuance of retainers (mean 5.9 years). If the expander was properly fabricated, and turned no more than once a day, the procedure was well-tolerated. Rapid maxillary expansion in adults flared the molars buccally only 3 degrees per side. The mandibular plane and lower facial height were unchanged. The adults achieved 18% of their transmolar expansion at the height of the palate and the remainder with buccal displacement of the alveolus. The children achieved 56% of their expansion by an increase at the height of the palate with the remainder due to displacement of the alveolus. There was some buccal attachment loss (0.6 +/- 0.5 mm) seen in the female subjects associated with RME, but the extent was clinically acceptable. This resulted in significantly longer clinical crowns, but rarely caused exposure of buccal root cementum. Complications were infrequently observed or of minimal consequence. The results indicate that nonsurgical RME in adults is a clinically successful and safe method for correcting transverse maxillary arch deficiency.

A survey of participation in managed care programs by endodontic specialists.

A survey was published in the Quarterly Survey of Dental Practice (QSDP) Special Topics that dealt with contractual agreements in dentistry. This survey evaluated general dental practitioner participation apart from that of dental specialists in general. The Quarterly Survey of Dental Practice survey was modified and used in the present study to specifically determine the participation by endodontists in various contractual insurance agreements, including Preferred Provider Organization and Health Maintenance Organization programs. A 10% sample of practicing endodontists was randomly selected to participate in this survey. Questionnaires (331) were sent out, and 229 or 69% were returned. Total participation by endodontists responding to this survey in any Health Maintenance Organization and/or Preferred Provider Organization insurance plans was 31.3%; however the total percentage of patients treated under these insurance plans was only 6.6%. These results were similar to those in the 1994 survey in which it was shown that 27% of the general dental practitioners and 41% of the dental specialists participated in one or more of these insurance programs and treated respectively, 5% and 9%, of their patients under these plans. Although participation in various managed care programs by endodontists in this survey was close to one-third, the total number of patients treated under these plans was low. Overall patients treated under fee-for-service arrangements by endodontists responding to this survey formed 85.3% of their patient pool. It does not appear from the results of this survey that managed care insurance has a significant impact on the practice of endodontics. It can be postulated that endodontists are unwilling to accept more than a small reduction in fees to join managed care plans, and they also desire to retain full control of their dental practice.

A comparison of the effects of rectangular and round arch wires in leveling the curve of Spee.

A prospective randomized clinical study was designed to evaluate the effects of full continuous arch wires, rectangular in cross section, on the axial inclination of lower incisors. The intention of rectangular arch wires is to counteract the labial crown moment usually produced during leveling the curve of Spee with full arch mechanics. Patients were randomly assigned to 2 groups. Group 1 (N = 12) received round arch wires throughout the leveling stage. Group 2 (N = 16) started with flat 0.016 x 0.022 nickel titanium arch wires progressing to 0.016 x 0.022 stainless steel. The preadjusted 0.018 x 0.025 edgewise appliance was used in all cases. Lateral cephalometric radiographs and mandibular study models were taken before treatment and when the curve of Spee was leveled (or in some cases when the overbite was considered clinically acceptable). In group 1, the lower incisor proclined a mean of 6.75 degrees +/- 4.85 degrees (P <.01) and in group 2 it proclined a mean of 6.10 degrees +/- 3.95 degrees (P <.01). However, no significant difference in proclination was detected between the 2 groups. Statistically significant, but low, correlations were demonstrated between change in lower incisor axial inclination and relief of crowding r = 0.45) and change in mandibular arch depth r = 0.54), which was in turn inversely correlated with change in intercanine width r = -0.45). In both groups, the lower incisors proclined with uncontrolled tipping that can probably be attributed to the intrusive force introduced by the arch wire being labial to the center of resistance of the lower incisors. The ability of the rectangular arch wires to control labial proclination following leveling of the curve of Spee, as used in this study, was not supported.

Assessment of 3-dimensional computer-generated cephalometric measurements.

The purpose of this study was to assess the reliability of 3-dimensional computer-generated linear and angular measurements produced by different computer algorithms and various combinations of cephalogram projections compared with direct and CT measurements. A computer program was written to provide 4 computer algorithms and 4 combinations of cephalogram projections generating 22 linear and 10 angular 3-dimensional measurements from 20 landmarks. A new technique to produce biplanar cephalograms from a single x-ray source using a special facebow was developed, and its reliability was assessed. Sets of lateral, frontal, and basilar cephalograms of a human dried skull were taken both with 20 radiopaque landmark markers and without markers. Paired t tests based on marker position demonstrated reliability of the facebow; there were no statistically significant differences in repositioning the skull over time using the facebow at P <.05. In the ideal situation, with minimal head rotation and landmark identification error (with the facebow and radiopaque markers), the average error of linear measurements was 1. 5 mm and 3.5(o) for the angular measurements. Subsequent trials evaluated the errors in head position (within 5(o) of head rotation) and in landmark identification (by removing all markers); two-way ANOVA with Scheffé groupings concluded that the vector intercept with manual adjustment algorithm using the lateral-frontal biplanar projection provides not only greater accuracy but also clinical practicality for both linear (mean of 2.2 mm error) and angular (mean of 4.0(o) error) measurements compared with direct or CT measurements (P <.05). The effect of landmark identification error was found to be slightly greater than the head rotation error in the accuracy of 3-dimensional linear and angular measurements (mean, 2.85 mm error for linear and 4.4(o) error for angular measurements). Lastly, this study concluded that linear measurements in the transverse direction were found to have a slightly larger error than vertical measurements. Anteroposterior measurements have the least error.

Comparison of effect of intracanal use of ketorolac tromethamine and dexamethasone with oral ibuprofen on post treatment endodontic pain.

The purpose of this study was to compare the pain-reducing efficacy of dexamethasone and ketorolac tromethamine when used as an intracanal medication, with oral ibuprofen and a placebo. An additional objective was to establish if any relationship exists between the incidence and severity of pretreatment pain and the incidence and severity of postinstrumentation pain. A total of 48 patients who presented to the University of Illinois postgraduate endodontic clinic were invited to participate. Patients were randomly assigned to 1 of 4 groups: oral ibuprofen, placebo, dexamethasone, or ketorolac tromethamine. Patients were asked to evaluate their pretreatment pain when they presented to the clinic with a Visual Analog Scale. The root canal treatment was performed in two appointments. The first appointment consisted of cleansing and shaping of the canal/s and placement of an intracanal medication. All teeth were closed with a sterile cotton pellet and IRM. Each patient was sent home with a Visual Analog Scale to fill out at 6, 12, 24 and 48 h after initiation of therapy. At the 12-h period, both dexamethasone and ketorolac provided statistically significant better pain relief than placebo. At the 24-h period, only ketorolac demonstrated better pain relief than the placebo. There were no statistically significant differences among the groups at 6 and 48 h. Although ibuprofen pain ratings were less than the placebo at all time points, the reduction was not significant. In addition, no significant differences were demonstrated between ibuprofen and either dexamethasone or ketorolac.

The effectiveness of protraction face mask therapy: a meta-analysis.

This study examined the effectiveness of maxillary protraction with orthopedic appliances in Class III patients. A meta-analysis of relevant literature was performed to determine whether a consensus exists regarding controversial issues such as the timing of treatment and the use of adjunctive intraoral appliances. An initial search identified 440 articles relating to Class III malocclusion. Among those articles, 11 studies in English and 3 studies in foreign languages met the previously established selection criteria. Data from the selected studies were categorized by age and appliance groups for the meta-analysis. The sample sizes were comparable between the groups. The statistical synthesis of changes before and after treatment in selected cephalometric landmarks showed no distinct difference between the palatal expansion group and nonexpansion group except for 1 variable, upper incisor angulation, which increased to a greater degree in the nonexpansion group. This finding implies that more skeletal effect and less dental change are produced in the expansion appliance group. Examination of the effects of age revealed greater treatment changes in the younger group. Results indicate that protraction face mask therapy is effective in patients who are growing, but to a lesser degree in patients who are older than 10 years of age, and that protraction in combination with an initial period of expansion may provide more significant skeletal effects. Overall mean values and corresponding standard deviations for the studies selected can also be used to estimate mean treatment effects expected from the use of protraction face mask.

Comparison of preferences in lip position using computer animated imaging.

The objectives of this study were to examine the esthetic preferences of lip position in males and females, and to compare them with each other and with a common orthodontic standard using a custom computer animation program. The sample consisted of 53 young adult subjects, 25 males and 28 females. The sample was divided into orthodontically treated and untreated subjects. ANOVA and Scheffé tests were carried out to determine differences between the responses of the various groups. Also, t-tests were used to compare subjects' responses to a commonly used orthodontic standard (Ricketts' E-line). The results indicated a sex-effect, with females preferring fuller lips than males. Significant differences were also found between orthodontically treated subjects and untreated subjects, with untreated subjects preferring fuller lips. Differences were significant at p<0.05. Furthermore, both males and females preferred lip fullness greater than the Ricketts' values.

Methodologies for evaluating long-term stability of dental relationships after orthodontic treatment.

A comprehensive review of literature which considers methodologies for studying long-term occlusal stability is presented. This article focuses on the evaluation of plaster study models because occlusal changes are best reflected in longitudinal casts. Of particular interest is the assessment of crowding in the dentition and the various physical and mathematical procedures used to evaluate the measurement of space available. Indices used to assess the overall occlusal results of treatment are also presented.

Computer-animated comparison of self-perception with actual profiles of orthodontic and nonorthodontic subjects.

To determine if motivation for adult orthodontic treatment is influenced by self-perception, a computer morphing program was developed to animate discrete digitized photographs of facial profiles. It was hypothesized that orthodontic patients are less tolerant of variations in their profiles than nonorthodontic patients. Sixteen orthodontic and 14 nonorthodontic adult patients were presented with animated distortions of 5 features of the lower third of their own profiles. They were asked to identify the zone of acceptability in the changing profile and to indicate the single most pleasing distortion and their perceived and preferred profiles, for comparison with their actual profile. Although orthodontic subjects did not differ from nonorthodontic subjects in the zone of acceptability of their own profiles, they were less tolerant (smaller zone of acceptability) of variation in features of a standard control face. Orthodontic subjects, however, had a larger disparity between the most pleasing and at least one feature of their actual profile than did the nonorthodontic subjects. Orthodontic and nonorthodontic subjects were equally accurate in their ability to identify their own profile features. This unique method of measuring self-perception offers the clinician the advantage of providing a dynamic range rather than a single point of acceptable change to the patient. Moreover, this interactive computer program will enable patients to actively participate in treatment planning decisions by communicating preferences for variations in facial profile distortions.

Presurgical profile preferences of patients and clinicians.

The purpose of this study was to compare the presurgical preferences for profile change of patients seeking orthognathic surgery with the preferences of "significant others" and clinicians. In this study, five features of lateral profile images of 11 patients scheduled for orthognathic surgery limited to the mandible (ie, set-back or advancement) were animated for continuous change with the use of customized morphing software and video imaging. Each patient profile was evaluated by the patient, a significant other, three orthodontists, and three oral surgeons. As the feature animated between two extremes, the zone of acceptability was established by depressing the computer mouse when the changing feature became acceptable and releasing the button when the image was no longer acceptable. In a separate task, the participants were asked to indicate the most pleasing position. An analysis of variance was used to find a significant difference (P <.017) in the zone of acceptability for all five profile features among all groups of evaluators. From smallest to largest, the order of the mean zone of acceptability was: orthognathic patient < oral surgeon < significant other < orthodontist. No consistent differences were found, however, for either the midpoint of acceptability or most pleasing distortion among the patients, significant others, and professional groups. In conclusion, it was demonstrated that (1) patients having orthognathic surgery were able to use this new video imaging method to communicate to clinicians what they find acceptable; and (2) although all groups had similar preferences, orthognathic patients had the lowest tolerance for deviation from the preferred image.

Effectiveness and duration of orthodontic treatment in adults and adolescents.

The purpose of this investigation was to compare the effectiveness and duration of orthodontic treatment in adults and adolescents with a valid and reliable occlusal index. Another aim was to evaluate variables that may influence the effectiveness and duration of orthodontic treatment in general. Pretreatment and posttreatment study models were scored using the Peer Assessment Rating Index. The difference in scores between pretreatment and posttreatment stages reflects the degree of improvement and therefore the effectiveness of treatment. Variables that reflect patient compliance were recorded from written treatment records from three private orthodontic practices. The sample consisted of 32 adults (mean age, 31.3 years) and 40 adolescents (mean age, 12.9 years), all of whom had four premolars extracted as part of the treatment strategy. The results indicated that there were no statistically significant differences (P > .05) between adults and adolescents regarding treatment effectiveness (occlusal improvement) and treatment duration. Multiple regression techniques revealed that the number of broken appointments and appliance repairs explained 46% of the variability in orthodontic treatment duration and 24% of the variability in treatment effectiveness. Furthermore, orthodontic treatment of the buccal occlusion and overjet explained 46% of the variability in treatment duration.

Opening rotations of the mandible during and after treatment.

In this retrospective cephalometric study of mandibular rotational change, we studied 60 cases. All patients were treated with full fixed appliances and exhibited an opening rotation of at least 1.5 degrees during treatment, as measured on the basis of the angle of the Y-axis to the sella-nasion line (SN). Our objective was to determine whether this opening rotation was sustained during retention. Paired t tests were used to test the hypothesis that the treatment change or opening rotation was stable and that these patients did not return to their original mandible-to-cranium relationship in the posttreatment period. Stepwise regression analysis was used to determine which (if any) changes in the independent variables during treatment could predict the subsequent behavior of the angle of the mandibular plane to the SN and the angle of the Y-axis to the SN during retention. During treatment, the mean increase in the angle of the Y-axis to the SN was 2.43 degrees. After an average posttreatment period of 54 months, this angle was reduced on average by only 0.73 degrees. Stepwise linear-regression analysis indicated that none of the treatment changes seen in the independent variables strongly predicted the ensuing closing rotation seen during retention. The correlation coefficient between the Y-axis angle and the mandibular-plane angle during treatment was 0.67. Mandibular opening rotations as a consequence of orthodontic treatment do not invariably return to the pretreatment value, and their negative effects--although sometimes small--cannot be discounted. Because the preponderant evidence of a closing rotation occurs in the terminal pubertal growth stages, the net effect may be even more significant.

Compliance with infection-control procedures among Illinois orthodontists.

The authors of previous studies have reported an increasing percentage of orthodontists complying with infection-control procedures in their offices, yet compliance was found to be less than ideal. In this study we surveyed Illinois orthodontists to evaluate their compliance with the infection-control guidelines established by the American Dental Association and the Centers for Disease Control and Prevention. This study is an addition to a small number of studies in the field of orthodontics on infection-control procedures. The study population was taken from the World Directory of Orthodontists, which contains 374 listings for the state of Illinois. Responses were received from 140 orthodontists, for a response rate of 37%. Thirty-two percent of the responding orthodontists stated that they always wear masks; 13% said they never do. Almost 97% of the orthodontists said they always wear gloves, and no orthodontist reported never wearing gloves. Nearly 64% of the orthodontists reported always using eyewear, and 34% said they wear gowns, whereas only 5% do not wear eye protection and 35% never wear gowns. With regard to instruments and pliers, most of the orthodontists reported using dry-heat ovens (72% and 80%, respectively), whereas nearly 58% said they use chemical disinfection to some extent on instruments and 39% said they use chemical disinfection on pliers. Only 51% of the orthodontists surveyed in our study reported using a steam autoclave to sterilize handpieces, whereas 27% said they use dry-heat ovens, 11% reported using chemical vapor, and 37% said they use chemical disinfection. In conclusion, compliance with infection control procedures among orthodontists has improved from recent studies but is still less than full compliance.

A new method for analyzing change in dental arch form.

Our method was developed and subsequently computerized in a system incorporating graphics and quantitative indexes to analyze change in dental arch form as a result of orthodontic treatment and subsequent relapse. The cubic spline function was used to model the form of the dental arches. On the basis of digitized data, splines were fitted to the dental arches before treatment, immediately after treatment, and at least 2 years after removal of retention. The fit of each spline was evaluated through the use of a set of normals to the curve and their average length. The change in form between the registrations was computed, and superimposed graphics of the three records were produced to visually indicate the magnitude of the changes in addition to numeric indexes that reflected the changes. Interjudge and intrajudge reliability were examined and found to be within acceptable limits.

An in vivo evaluation of an electronic apex locator that uses the ratio method in vital and necrotic canals.

The purpose of this study was to compare the canal length determined by an apex locator to the apical constriction in both vital and necrotic canals. Informed consent was obtained from patients waiting to have teeth extracted. The teeth were anesthetized, isolated, and accessed. The pulp was considered vital if bleeding was present in the pulp chamber. The Root ZX was used to measure the root canal length. The file was cemented into place, and the tooth was extracted. Twenty-nine teeth containing 34 cemented files were studied, and the distance from the apical constriction was measured. The Root ZX was 82.3% accurate to within 0.5 mm of the apical constriction. The mean distance from the apical constriction was 0.21 mm in vital cases versus 0.49 mm for necrotic cases. There was no statistical difference between the ability of the Root ZX to determine the apical constriction in vital canals versus necrotic canals.

Evaluation of orthodontic relapse using the cubic spline function.

A sample of 72 orthodontically treated patients was reexamined many years out of retention. They had been treated either by the extraction of four premolars or without extractions. The average number of years between the end of treatment and the taking of follow-up records was 20, with a range of 12 to 35 years. Some conventional measurements were studied such as intertooth widths, arch perimeter, and incisor irregularity. In addition, a new method for comparison of arch form at different stages of treatment, which uses the cubic spline function, was used. Cases were grouped into extraction and nonextraction, and statistics were used to test the differences between the two groups. Correlations between the spline variables and conventional variables were computed, and multiple regression analysis was carried out using the spline variables as dependent variables. Some treatment and relapse changes were independent of whether the case was treated with extractions or not, whereas other trends were unique to one treatment group. The correlation analysis revealed strong relationships between variables that measured changes during the same treatment stage. There were also moderate correlations between some of the spline variables and the traditional measurements. Multiple regression analysis was used to account for changes in some spline variables, however, the usefulness of the model as a predictor is limited.

Analysis of change in arch form with premolar expansion.

The arch forms of 38 cases (53 nonextraction and 23 extraction arches) in which expansion, while maintaining arch form, was the objective of the practitioner, were analyzed before treatment, after treatment, and an average of 6 to 8 years after retention. The cubic spline was used to fit a curve representing arch form. By superimposing the spline curves, changes in arch form were analyzed with the variables rebound change (RC), rebound index (RI), rebound number (RN), and stability number (SN). Traditional linear intraarch dimensions were also analyzed. Analysis of variance was used to determine differences between the maxillary and mandibular arches and between the extraction and nonextraction cases. Pearson correlation coefficients between spline variables and arch width variables were also computed. There was significantly more expansion in the maxillary arch than the mandibular arch during treatment, irrespective of extraction or nonextraction strategies. In the nonextraction cases, a greater amount of net expansion was achieved for all dimensions for the maxillary arch as compared with the mandibular arch. Overall, a relatively high stability in arch form was found. The findings suggest that stability may not be related to the amount of change produced during treatment. Significant expansion can be gained throughout the premolar regions and may be expected to be stable. The order of greatest net arch width gained was for the second premolars followed by first premolars, molars, and then the canines. The intercanine widths for both arches decreased toward pretreatment values, but were more stable in the maxillary arch in nonextraction cases. The cubic spline permits measurement of change in arch form both during treatment and retention periods.

Endodontic patient recall procedures: a national survey of endodontic practices.

A survey was conducted to measure the extent of patient recall procedures and perceived success and failure in treatment from a sample of endodontists. A comparison to the accepted Quality Assurance Guidelines set forth by the American Association of Endodontists was conducted. Three hundred surveys were mailed to as many active members of the American Association of Endodontics. Two hundred thirty-three responses were returned for a response rate of 77.6%. The only statistically significant finding was that military practitioners in general do not have an active recall system. This was significant at the p < 0.008 level.

Bond strength of visible light-cured glass ionomer orthodontic cement.

In this in vitro study, tensile strength tests were conducted with a visible light-cured glass ionomer cement (Fuji Ortho LC, GC America Inc.) bonded to extracted teeth under six different enamel surface conditions: (1) dry nonetched, (2) moist etched, (3) moist nonetched, (4) moist nonetched rebonded, (5) moistened with saliva substitute, and (6) moistened with human saliva. Two resin adhesives (Rely-A-Bond and Phase II, Reliance Orthodontic Products) were applied to dry and etched enamel and served as control agents. The glass ionomer cement approached the strength observed for resin adhesives and required the presence of moisture on the enamel surface for optimal performance.

National survey of endodontists and selected patient samples: infectious diseases and attitudes toward infection control.

A survey was conducted of 591 patients from endodontic practices located in six large municipalities in the United States. A comparison was made between the self-reported incidence of transmissible diseases from patients medical histories to national statistics for the incidence of hepatitis B, herpes, tuberculosis, and HIV/AIDS. A national survey of 422 endodontists was also conducted. This survey was used to determine the beliefs and attitudes of practicing endodontists toward infection control techniques and infectious diseases. Compared with previous surveys, a trend toward increasing use of the hepatitis B vaccine, gloves, and greater acceptance of medically compromised patients was found.