Stella Efstratiadis

Comparison of space analysis evaluations with digital models and plaster dental casts

INTRODUCTION Diagnostic measurements have traditionally been made on plaster dental casts. Now, 3-dimensional digital dental models can be used. The purpose of this study was to compare space analysis measurements made on digital models with those from plaster dental casts. METHODS Two sets of 25 alginate impressions were taken of patients who had a permanent Class I crowded dentition. Each impression was made into a plaster cast and a 3-dimensional virtual orthodontic model (OrthoCad, Cadent, Fairview, NJ). Measurements of tooth widths at their greatest mesiodistal dimension and arch length were recorded for both types of models. Tooth widths were measured on the plaster models with a digital caliper, and arch length was measured with a piece of brass wire and a millimeter ruler. The virtual models were measured by using OrthoCads dedicated software. The space analysis measurements were calculated for both types of models, and the extrapolated amount of crowding for each type of model was accessed. All measurements were made by 2 examiners. The resulting values were compared with nonparametric statistics, and method errors were calculated. RESULTS When comparing digitized models with conventional plaster dental study models, we found a slight (0.4 mm) but statistically significant difference in the space analysis measurements on the maxillary models; measurements on the mandibular models were not significantly different. No significant difference was found between the measurements of the 2 examiners. CONCLUSIONS The accuracy of the software for space analysis evaluation on digital models is clinically acceptable and reproducible when compared with traditional plaster study model analyses.

Interleukin-1β and β-Glucuronidase in gingival crevicular fluid from molars during rapid palatal expansion

Abstract This study examined whether the inflammatory mediators interleukin (IL-1β) and β-glucuronidase (βG) are present in the gingival crevicular fluid (GCF) of children undergoing rapid palatal expansion and whether their levels vary upon activation of the appliance and movement of the maxillary first molars. Nine adolescent patients who needed palatal expansion were studied. Each patient received a periodontal prophylaxis and instruction in proper home care, including rinsing with chlorhexidine. Four weeks later, a modified Hyrax appliance was inserted. The jackscrew was activated twice daily until the appropriate expansion was achieved. GCF samples were collected at 2 pretreatment observation periods and 9 observation periods after placement of the appliance. Samples were collected with filter paper strips and analyzed by means of ELISA and time-dependent fluorometry for IL-1β and βG, respectively. The values recorded at the observation period 2 weeks after the periodontal prophylaxis were used as baseline. Paired t tests were used to compare mediator levels at this baseline to the levels obtained at each of the subsequent observations. The results indicate that (1) βG and IL-1β are present in GCF of young, healthy individuals, (2) their levels decrease following a strict regimen of plaque control, (3) orthodontic/orthopedic forces evoke changes in the levels of the inflammatory mediators IL-1β and βG in the periodontal tissues that can be detected in GCF. The results of this study support the hypothesis that mechanical stimulus causes an inflammatory reaction within the periodontal tissues, which in turn may trigger the biological processes associated with bone remodeling. (Am J Orthod Dentofacial Orthop 1998; 114: 686-96)

Comparison of levels of inflammatory mediators IL-1β and βG in gingival crevicular fluid from molars, premolars, and incisors during rapid palatal expansion

INTRODUCTION Previously, we reported fluctuation of the levels of the inflammatory mediators interleukin-1beta (IotaL-1beta) and beta-glucuronidase (betaG) in gingival crevicular fluid (GCF) from the maxillary first molars in adolescents undergoing rapid palatal expansion. In this study, we compared the responses of IL-1beta and betaG in the GCF of the maxillary first molars, first premolars, and central incisors during palatal expansion at the same patients. METHODS Nine patients requiring palatal expansion were selected at the postdoctoral orthodontic clinic at Columbia University College of Dental Medicine. Each patient received periodontal prophylaxis and instructions in proper home care including rinsing with chlorhexidine. Four weeks after periodontal prophylaxis, a modified hyrax appliance was placed. The jackscrew was activated twice daily until the appropriate expansion was achieved. GCF samples were collected before and after periodontal prophylaxis and during passive wearing of the appliance, active orthodontic treatment, and retention. Fluid samples were collected with filter paper strips and analyzed by ELISA and time-dependent fluorometry for IL-1beta and betaG, respectively. The values recorded after periodontal prophylaxis were used as the baseline. Paired t tests were used to compare mediator levels at baseline with the levels obtained at each subsequent observation. RESULTS The results validate that IL-1beta and betaG are present in the GCF of adolescents, and, although their level decreases after a strict regimen of plaque control, it increases during orthodontic or orthopedic movement. Moreover, this study demonstrates that both heavy and light forces evoke increased levels of IL-1beta and betaG, stronger forces cause higher levels of inflammatory mediators, and both IL-1beta and betaG respond to direct and indirect application of mechanical force to teeth. CONCLUSIONS This investigation corroborates previous findings that an inflammatory process occurs during application of mechanical force to teeth. Although this inflammation is considered relatively aseptic, additional inflammation, such as that induced by plaque accumulation, must be avoided during orthodontic or orthopedic treatment.

Evaluation of differential growth and orthodontic treatment outcome by regional cephalometric superpositions.

Cephalometric superimposition on cranial base is the accepted method for evaluating mandibular displacement during orthodontic treatment and/or growth. However, assessing mandibular position relative to the maxillary base may yield different information. The aim of this study was to evaluate the effects of regional superpositions (cranial versus maxillary) on interpreting mandibular displacement. Both methods were applied to pre- and posttreatment cephalograms of 22 growing children (12 female, 10 male) treated for Class II Division 1 malocclusion. Differences in linear and angular measurements of three mandibular landmarks (pogonion, gnathion, menton) between cranial and maxillary superpositions were statistically significant (p = 0.0001). Vertical displacement of these landmarks contributed significantly to the differences (p = 0.0001). The contribution of horizontal displacement was not statistically significant. The results support the proposition that, in growing children, posttreatment displacement of mandibular skeletal and dental components should be assessed by both maxillary and cranial base superimpositions. The maxilla is subject to rotational and translational changes during growth that may affect the position of the mandible relative to the maxilla in a way inconsistent with the mandibular displacement perceived upon cranial superposition. Since occlusion is directly associated with the positions of the maxillary and mandibular basal bones, the positions of these bones relative to each other is critical in assessing occlusal changes in individual patients.

Mandibular displacement and dentitional changes during orthodontic treatment and growth

Mandibular displacement during orthodontic treatment and/or growth is usually analyzed through cephalometric superposition on the cranial base. Evaluation of mandibular movement in relation to the maxillary base has considerable value because the occlusion of the teeth is associated directly with the position of the maxillary and mandibular basal bones. The method of superimposition is outlined and applied to a number of treated malocclusions. Incorporation of this method in the study of treatment results is suggested.

Pulp vitality after rapid palatal expansion

INTRODUCTION Although it has been suggested that orthodontic treatment might lead to changes in the dental pulp, no clinical study has attempted to investigate the incidence of pulp necrosis after orthodontic therapy. The purpose of this clinical trial was to determine whether pulp testing response is altered after rapid palatal expansion (RPE). METHODS Twenty-five adolescent patients (9 boys, 16 girls; ages, 10-16 years) participated in the study. A hyrax appliance was cemented on the first permanent molars and first premolars (when fully erupted). The appliance was activated twice daily (0.5 mm) for 2 weeks. An electric pulp tester (EPT) was used to test at the buccal cusp tips of the molars and premolars. Teeth that did not respond to the EPT were subsequently tested thermally with Endo Ice (Hygienic Corporation, Akron, Ohio). RESULTS All maxillary molars and erupted premolars of the 25 patients responded positively to pulp tests before cementation of the hyrax appliance. Of the 49 molars tested, 46 responded positively to the EPT, and 3 responded positively to the cold testing (CT). Of the 42 first premolars tested, 40 responded positively to the EPT and 2 to the CT. Of the 38 second premolars tested, 35 responded positively to the EPT and 3 to the CT. Two weeks after the initial activation of the hyrax appliance, 93 teeth in 17 subjects were tested. Of the 93 teeth, 73 teeth responded positively to the EPT and 20 to the CT. Three to 6 weeks after hyrax activation was discontinued, 59 teeth were tested; 48 tested positively to the EPT and 10 to the CT. One tooth (maxillary left first molar) did not respond to either EPT or CT. Finally, 3 to 9 months into retention, all molars and premolars of 23 subjects tested positive to pulp tests, 92 teeth to the EPT and 25 to the CT. The maxillary left first molar that had not responded to the tests at the 3-to-6 week check responded positively to the CT at the final check. CONCLUSIONS After RPE therapy in children and adolescents, the pulp of the posterior permanent teeth examined in this study was vital.

An American board of orthodontics case report: Treatment of an open bite malocclusion

The patient had a Class I (Angle) malocclusion characterized by an anterior open bite, bimaxillary dental protrusion, posterior and anterior crossbites, and mandibular midline deviation. A nonextraction treatment was followed for this patient. A Begg appliance (0.020 inch) and a posterior high-pull headgear were used. The prognosis was good because of the rather favorable skeletal pattern of the patient. The active treatment lasted 12 months. The patient was retained with a positioner. The occlusion was stable at 2 years posttreatment. [This case was presented to the American Board of Orthodontics in partial fulfillment of the requirements for the certification process conducted by the Board.]