Christina Erbe

Plaque levels of patients with fixed orthodontic appliances measured by digital plaque image analysis.

INTRODUCTION A digital plaque image analysis system was developed to objectively assess dental plaque formation and coverage in patients treated with fixed orthodontic appliances. METHODS The technique was used to assess plaque levels of 52 patients undergoing treatment with fixed appliances in the Department of Orthodontics at Johannes Gutenberg University in Mainz, Germany. RESULTS Plaque levels ranged from 5.1% to 85.3% of the analyzed tooth areas. About 37% of the patients had plaque levels over 50% of the dentition, but only 10% exhibited plaque levels below 15% of tooth coverage. The mean plaque coverage was 41.9% ± 18.8%. Plaque was mostly present along the gum line and around the orthodontic brackets and wires. CONCLUSIONS The digital plaque image analysis system might provide a convenient quantitative technique to assess oral hygiene in orthodontic patients with multi-bracket appliances. Plaque coverage in orthodontic patients is extremely high and is 2 to 3 times higher than levels observed in high plaque-forming adults without appliances participating in clinical studies of the digital plaque image analysis system. Improved hygiene, chemotherapeutic regimens, and compliance are necessary in these patients.

The Mechanism of Class II Correction in Surgical Orthodontic Treatment of Adult Class II, Division 1 Malocclusions

The purpose of this investigation was to assess the dentoskeletal effects and facial profile changes as well as the mechanism of Class II correction in adult Class II subjects treated by surgical mandibular advancement in combination with orthodontics. The subject material comprised 46 adults with a Class II, division 1 malocclusion treated by nonextraction with a mandibular sagittal split osteotomy as well as with pre- and postsurgical multibracket appliances. Lateral head films from before treatment and after treatment were analyzed. The results revealed the following statistically significant (P < .001) treatment changes: (1) the mandibular prognathism enhanced; (2) the sagittal interjaw base relationship improved; (3) the mandibular plane angle increased; (4) the lower anterior facial height increased; (5) the lower posterior facial height decreased; (6) the facial profile straightened; (7) the overjet and Class II molar relationship were corrected. Overjet reduction was accomplished by 63% skeletal and 37% dental changes. The Class II molar correction was accomplished by 81% skeletal 19% dental changes. In conclusion, it can be said that mandibular sagittal split osteotomy in combination with pre- and postsurgical orthodontics is an effective and consistent method for the correction of Class II, division 1 malocclusions and for the straightening of the facial profile. A negative effect of treatment counteracting Class II correction is an increase in the mandibular plane angle.

Influence of prolonged setting time on permanent deformation of elastomeric impression materials.

STATEMENT OF PROBLEM Upon removal, tear forces occur in various areas of an impression. As a result, thin sulcus details may be permanently deformed, affecting the impressions accuracy. PURPOSE The purpose of this study was to investigate the effect of the chemistry and prolonged setting time on the permanent deformation of light-body impression materials after stretching. MATERIAL AND METHODS A dumbbell-shaped mold (2 mm x 4 mm x 75 mm) was used to prepare specimens (n=20) of 6 different impression materials (Affinis Light Body, Aquasil Ultra XLV, Express 2 Light Body Flow Quick, Flexitime Correct Flow, P2 Polyether Light, and Impregum Garant L DuoSoft). After water storage (35 degrees C), either for the manufacturers suggested setting time or for 5 minutes, specimens were stretched by 80% using a universal testing machine at a crosshead speed of 200 mm/min. The permanent deformation (Deltal (%)) was determined after 2 hours of storage in ambient conditions. A 2-way ANOVA followed by a Games-Howell test was used to analyze the influence of material and storage time (alpha=.05). RESULTS Polyether materials showed a significantly higher permanent deformation (Deltal>4% to 5%) than vinyl polysiloxane materials (P<.05). Extending the manufacturers suggested setting time resulted in clinically relevant improvements in elastic recovery for products with a polyether backbone only. CONCLUSIONS Increasing the setting time might be necessary for impression materials with a polyether backbone to improve elastic recovery.

Efficacy of 3 toothbrush treatments on plaque removal in orthodontic patients assessed with digital plaque imaging: A randomized controlled trial

INTRODUCTION Good oral hygiene is a challenge for orthodontic patients because food readily becomes trapped around the brackets and under the archwires, and appliances are an obstruction to mechanical brushing. The purpose of this study was to compare plaque removal efficacy of 3 toothbrush treatments in orthodontic subjects. METHODS This was a replicate-use, single-brushing, 3-treatment, examiner-blind, randomized, 6-period crossover study with washout periods of approximately 24 hours between visits. Forty-six adolescent and young adult patients with fixed orthodontics from a university clinic in Germany were randomized, based on computer-generated randomization, to 1 of 3 treatments: (1) oscillating-rotating electric toothbrush with a specially designed orthodontic brush head (Oral-B Triumph, OD17; Procter & Gamble, Cincinnati, Ohio); (2) the same electric toothbrush handle with a regular brush head (EB25; Procter & Gamble); and (3) a regular manual toothbrush (American Dental Association, Chicago, Ill). The primary outcome was the plaque score change from baseline, which we determined using digital plaque image analysis. RESULTS Forty-five subjects completed the study. The differences in mean plaque removal (95% confidence interval) between the electric toothbrush with an orthodontic brush head (6% [4.4%-7.6%]) or a regular brush head (3.8% [2.2%-5.3%]) and the manual toothbrush were significant (P <0.001). Plaque removal with the electric toothbrush with the orthodontic brush head was superior (2.2%; P = 0.007) to the regular brush head. No adverse events were seen. CONCLUSIONS The electric toothbrush, with either brush head, demonstrated significantly greater plaque removal over the manual brush. The orthodontic brush head was superior to the regular head.

Dimensional stability of contemporary irreversible hydrocolloids: Humidor versus wet tissue storage

STATEMENT OF PROBLEM The storage time and conditions of irreversible hydrocolloid impressions affect their accuracy and in turn the precision of the definitive cast. Recommendations for proper storage are, however, based on theoretical assumptions rather than facts. PURPOSE The purpose of this study was to assess the influence of the 2 most common storage conditions on the dimensional stability of 7 contemporary irreversible hydrocolloids (IH) for a period of up to 7 days. MATERIAL AND METHODS Twelve specimens per material (Blueprint, Cavex CA37, Cavex ColorChange, Jeltrate, Orthoprint, Cavex Orthotrace, and Tetrachrom) were fabricated according to ISO/CD 21563. The specimens were either stored in a humidor (n=6) or wrapped in a wet tissue (n=6) inside a plastic bag (bag/tissue). The linear dimensional change of the specimens was calculated (Δ| [%]) at baseline and after a storage time of 1, 2, 4, 24, 48, 72, 120, and 168 hours. Data were subjected to a repeated measures ANOVA, followed by post hoc comparisons (Tukey HSD Test, Games-Howell Test) at α=.05. RESULTS For specimens stored in the humidor, Δ| ranged from 0.33% to -2.35% and in the bag/tissue from 2.89% to -2.8%. Storage in the bag/tissue resulted in the most unpredictable results. The color-changing IH showed a pronounced expansion when stored in the bag/tissue. CONCLUSIONS If humidor storage is used, IH impressions should be poured within 4 hours. If bag/tissue storage is used, noncolor-change IH impressions should, preferably, be poured within 2 hours. In general, the color-change IHs studied had higher dimensional change values. For optimum dimensional stability, IH impressions should be poured as soon as possible.

Motion analysis in the field of dentistry: a kinematic comparison of dentists and orthodontists

Objectives To conduct a kinematic comparison of occupational posture in orthodontists and dentists in their workplace. Design Observational study. Setting Dentist surgeries and departments of orthodontics at university medical centres in Germany. Participants A representative sample of 21 (10 female, 11 male) dentists (group G1) and 21 (13 female, 8 male) orthodontists (G2) with one male dropout in G2. Outcome measures The CUELA (computer-assisted acquisition and long-term analysis of musculoskeletal loads) system was used to analyse occupational posture. Parallel to the recording through the CUELA system, a software-supported analysis of the activities performed (I: treatment; II: office; III: other activities) was carried out. In line with ergonomic standards the measured body angles are categorised into neutral, moderate and awkward postures. Activities between the aforementioned groups are compared using the stratified van Elteren U test and the Wilcoxon–Mann–Whitney U test. All p values are subject to the Bonferroni–Holm correction. The level of significance is set at 5%. Results The percentage of time spent on activities in categories I–II–III was as follows: dentists 41%–23%–36% and orthodontists 28%–37%–35%. The posture analysis of both groups showed, for all percentiles (P5–95), angle values primarily in the neutral or moderate range. However, depending on the activity performed, between 5% and 25% of working hours were spent in unfavourable postures, especially in the head-and-neck area. Orthodontists have a greater tendency than dentists to perform treatment activities with the head and torso in unfavourable positions. The statistically significant differences between the two groups with regard to the duration and the relevance of the activities performed confirm this assumption for all three categories (p<0.01, p<0.05). Conclusions Generally, both groups perform treatment activities in postures that are in the neutral or medium range; however, dentists had slightly more unfavourable postures during treatment for a greater share of their work day.

Influence of dental occlusion on postural control and plantar pressure distribution.

Abstract Objective: The number of studies investigating correlations between the temporomandibular system and body posture, postural control or plantar pressure distribution is continuously increasing. If a connection can be found, it is often of minor influence or for only a single parameter. However, small subject groups are critical. This study was conducted to define correlations between dental parameters, postural control and plantar pressure distribution in healthy males. Methods: In this study, 87 male subjects with an average age of 25.23 ± 3.5 years (ranging from 18 to 35 years) were examined. Dental casts of the subjects were analyzed. Postural control and plantar pressure distribution were recorded by a force platform. Possible orthodontic and orthopedic factors of influence were determined by either an anamnesis or a questionnaire. All tests performed were randomized and repeated three times each for intercuspal position (ICP) and blocked occlusion (BO). For a statistical analysis of the results, non-parametric tests (Wilcoxon-Matched-Pairs-Test, Kruskall-Wallis-Test) were used. A revision of the results via Bonferroni-Holm correction was considered. Results: ICP increases body sway in the frontal (p ≤ 0.01) and sagittal planes (p ≤ 0.03) compared to BO, whereas all other 29 correlations were independent of the occlusion position. For both of the ICP or BO cases, Angle-class, midline-displacement, crossbite, or orthodontic therapy were found to have no influence on postural control or plantar pressure distribution (p > 0.05). However, the contact time of the left foot decreased (p ≤ 0.001) while detecting the plantar pressure distribution in each position. Conclusions: Persistent dental parameters have no effect on postural sway. In addition, postural control and plantar pressure distribution have been found to be independent postural criteria.