Three-dimensional analysis of posttreatment tooth movements despite bonded retainers: part I-upper jaw.

PURPOSE: Adverse side effects of fixed retainers in terms of unwanted tooth movements have been described for both the upper and lower jaw, but data about the extent and movement patterns for the maxilla are scarce. The purpose of the present retrospective case-control study was to analyze the amount and direction of unwanted tooth movements despite upper bonded retainers as well as to analyze possible predisposing pretreatment- and treatment-related factors. METHODS: Plaster casts of 1026 patients who completed orthodontic treatment and a subsequent retention phase of 2 years were screened for unintentional tooth movements. The study group comprised 57 patients with visually obvious tooth movements in the upper jaw, while 57 randomly selected patients without visible tooth movements served as control group. For all patients, plaster casts after debonding of multibracket appliance (T1) and after supervised retention (T2) were digitized, and superimposed digitally using a stable palatal reference area. Thereafter, translational and rotational movements were measured in all three planes of space. Pretreatment- and treatment-related factors of the study and control groups were compared by χ2 test, exact Fisher test, Mann-Whitney U test, and the T­test for independent samples. RESULTS: The mean translational movements ranged between 0 and 0.6 mm and the average rotational movements between 0 and 1.3°. Large individual movements up to 2.7 mm translation and 15.9° rotation were seen. A movement pattern around the Y­ and Z­axis with an opposite rotational peak at the canines ("upper twist effect") was identified. Compared to the control group, patients of the study group showed a significantly smaller intercanine width pretreatment. Also, study group patients presented a larger intercanine expansion and a slightly larger overjet reduction during treatment, and were more often affected by retainer bonding site detachments and wire fractures, but without reaching statistically significance. CONCLUSION: Upper bonded retainers show a similar unwanted movement pattern ("twist effect") like the one described for mandibular retainers.

Three-dimensional analysis of posttreatment tooth movements despite bonded retainers: part II-lower jaw.

PURPOSE: Complications of bonded lingual retainers in terms of unexpected tooth movements have been reported with increasing frequency during the last decade, but the vast majority of the literature comprises case reports. The purpose of the present retrospective case-control study was to analyze the amount and direction of unwanted tooth movements despite lower bonded retainers, to analyze possible predisposing pretreatment- and treatment-related factors, and to seek for movement thresholds which could enhance the rapid and objective identification of critical cases. METHODS: Plaster casts of 1026 patients who completed orthodontic treatment and a subsequent retention phase of 2 years were screened for unintentional tooth movements. The study group comprised 39 patients with tooth movements in the lower jaw, while 39 randomly selected patients without visible tooth movements served as the control group. For all patients, plaster casts after debonding of multibracket appliances (T1) and after supervised retention (T2) were digitized, and a three-dimensional (3D) digital superimposition based on the best fit of premolars and molars was undertaken. Thereafter, translational as well as rotational movements were measured in all three planes of space. Pretreatment- and treatment-related factors of the study and control groups were compared. A severity classification based on rotational movement thresholds was applied to seek a critical amount of translational movements. RESULTS: The mean translational movements ranged between 0 and 0.4 mm and the average rotational movements between 0 and 1.6°. Large individual movements up to 1.9 mm translation and 16° rotation were seen. A twist-effect with opposite movements of the canines along the Y­axis could be confirmed. Compared to the control group, patients of the study group had a smaller intercanine distance at all timepoints. In addition, study group patients presented a slightly larger intercanine expansion during treatment and were more often affected by retainer bonding site detachments. Applying the severity classification based on rotational thresholds, translational movements of 0.5-1.0 mm along the X­ and Y­axis could serve as a critical threshold. It can be assumed that extrusive translational movements along the Z­axis seem to be of specific nature and perhaps do not reflect a retainer complication in terms of unwanted tooth movements. CONCLUSIONS: Patients with a larger intercanine distance after active treatment and those with more frequent retainer bonding site detachments could be at higher risk for unwanted tooth movements during fixed retention. Sagittal and transverse movements of 0.5-1.0 mm should sensitize the practitioner for further measures.

Caries and white spot lesion trajectories of orthodontic patients across an observation period of 20 years.

OBJECTIVES: Fixed orthodontic appliances may increase the risk for caries and white spot lesions. The aim of this retrospective study was to determine the long-term associations between both in orthodontic patients. MATERIALS AND METHODS: 103 patients aged 36.6 ± 6.5 years whose fixed appliance orthodontic treatment had finished at least 15 years ago were included. Current clinical data and photographs (T3), panoramic x-ray and photographs from before treatment (T0), after debonding (T1) and at 2-year follow-up (T2) were available. Parameters of interest were dentine caries, "Missing/Filled Teeth" (MFT), "White Spot Lesion" (WSL) index and "Periodontal Screening and Recording" index (PSR; T3 only). RESULTS: At T0, 30.4% had no caries experience decreasing to 25.6%, 22.4% and 6.8% at T1, T2 and T3 resp. The median MFT (95% CI) at T0, T1, T2 and T3 was 2 (1;3), 3 (2;4), 3 (2;4) and 7 (6;9) resp. increasing significantly at each time point (p < 0.001 each); 30.1% had WSL at debonding. Patients with caries experience at T0 had a 2.4-fold increased risk of WSL at debonding. Dentine caries, caries experience and WSL at T1 were significantly associated with incident caries at T2, but not at T3. PSR at T3 had a significant association with previous caries incidence and WSL. CONCLUSIONS: Caries experience prior to orthodontic treatment may constitute a risk indicator for WSL, and caries experience and WSL at its end for caries incidence in the near term. CLINICAL RELEVANCE: Present caries and WSL may help identifying orthodontic patients with special need for prevention and counselling.

White spot lesions after fixed appliance treatment-Can we expect spontaneous long-term (≥15 years) improvement?

OBJECTIVE: To investigate the extent to which post-orthodontic white spot lesions (WSLs) change in appearance over a period of ≥15 years and whether an association with caries data exists. SUBJECTS AND METHODS: Seventy-two patients treated with a Herbst-Multibracket appliance at age 14.0 ± 2.7 years for 20.1 ± 5.1 months who attended a recall 18.3 ± 2.9 years post-treatment. Post-treatment (T1) intraoral photographs were assessed by a panel of five dentists using a modified version of the WSL-Index by Gorelick. For affected incisors, photographs from before treatment (T0) and recall (T3) were evaluated. In addition, the WSL-Change Index by Pancherz and Muehlich was assessed for all adequately visible incisors considering T1, T2 (if available), and T3. Radiographic (T0, T1, and T2-if available) and clinical (T3) MFT data were used. RESULTS: 37.5% of the patients exhibited WSLs on ≥ 1 incisor at T1; in total, 81 incisors (14.9%) were affected. At T3, 48% of the WSLs had improved. The modified WSL-Index decreased from 1.2 ± 0.4 to 0.8 ± 0.6 (P < .001), with a score 0 in 28% of the previously affected incisors. When comparing T2 vs. T3, additional improvement after T2 occurred in 11% of the teeth. While no difference existed at T0, the MFT values at T1, T2, and T3 were higher (P ≤ .05) in patients with WSLs at T1 than in those without. LIMITATIONS: The homogeneity of the subjects was limited and no patient-reported outcome was assessed. CONCLUSIONS: Long-term, post-orthodontic WSLs showed spontaneous full recovery in 28% and improvement in 48% of the teeth. Patients affected with WSLs exhibited higher post-treatment MFT values.

What to Prefer in Patients with Multibracket Appliances? Digital vs. Conventional Full-Arch Impressions-A Reference Aid-Based In Vivo Study.

This study aimed to investigate the transfer accuracy and required time for digital full-arch impressions obtained from intraoral scanners (IOSs) versus conventional alginate impressions (CAIs) in patients with multibracket appliances (MBA). Thirty patients with buccal MBAs (metal brackets, archwire removed) were examined using an established reference aid method. Impression-taking using four IOSs (Primescan, Trios 4, Medit i700, Emerald S) and one CAI with subsequent plaster casting were conducted. One-hundred-twenty (n = 30 × 4) scans were analyzed with 3D software (GOM Inspect) and 30 (n = 30 × 1) casts were assessed using a coordinate measurement machine. Six distances and six angles were measured and compared to the reference aid values (ANOVA; p < 0.05). Except for the intermolar distance, transfer accuracy was significantly higher with IOSs than with CAIs (p < 0.05). No such difference was found regarding the six angles. In patients with MBAs, digital impression-taking using IOSs can be recommended. For all measured variables except one, the transfer accuracy of IOSs was better than or at least equivalent to the data from CAIs. In addition, significantly (p < 0.001) less time was necessary for all IOSs in comparison to CAIs plus plaster casting.

The transfer accuracy of digital and conventional full-arch impressions influenced by fixed orthodontic appliances: a reference aid-based in vitro study.

OBJECTIVES: The aim of this in vitro study was to investigate the influence of fixed orthodontic appliances (FOAs) on the transfer accuracy of full-arch impressions by five intraoral scanners (IOSs): CS3600, Primescan, Trios 4, Medit i500, Emerald S, and one conventional alginate impression (CAI). MATERIALS AND METHODS: To compare the data with the actual model situation, an established reference aid-based method was applied. A test model with human teeth was used and modified for each testing group, resulting in five different settings: natural teeth (group A), metal brackets without/with wire (groups B/C), ceramic brackets without/with wire (groups D/E). A total of 300 (n = 12 × 5 × 5) scan datasets of IOSs were analyzed using a 3D software (GOM Inspect) and 60 (n = 12 × 5) plaster casts of CAI were measured with a coordinate measurement machine. The deviations between the reference aid and the impressions were determined. RESULTS: For all groups with brackets (B to E), IOSs showed a higher transfer accuracy compared to CAI, even for long-span distances. However, some significant differences between the IOSs were observed (p < 0.05). CONCLUSIONS: Within the limitations of this in vitro study, IOSs can be recommended for impressions with and without FOAs, even if CAI showed the smallest average deviations in settings without FOAs. CLINICAL RELEVANCE: IOSs are widely used in orthodontics and the current study demonstrated that their use enables fast impression taking even in settings with fixed orthodontic appliances. In addition, for these settings, the transfer accuracy is higher than with conventional alginate impressions. Nevertheless, a re-investigation in a clinical setting should be performed to verify the current in vitro findings.

Accuracy of a Smartphone Application Measuring Snoring in Adults-How Smart Is It Actually?

About 40% of the adult population is affected by snoring, which is closely related to obstructive sleep apnea (OSA) and can be associated with serious health implications. Commercial smartphone applications (apps) offer the possibility of monitoring snoring at home. However, the number of validation studies addressing snoring apps is limited. The purpose of the present study was to assess the accuracy of recorded snoring using the free version of the app SnoreLab (Reviva Softworks Ltd., London, UK) in comparison to a full-night polygraphic measurement (Miniscreen plus, Löwenstein Medical GmbH & Co., KG, Bad Ems, Germany). Nineteen healthy adult volunteers (4 female, 15 male, mean age: 38.9 ± 19.4 years) underwent simultaneous polygraphic and SnoreLab app measurement for one night at home. Parameters obtained by the SnoreLab app were: starting/ending time of monitoring, time in bed, duration and percent of quiet sleep, light, loud and epic snoring, total snoring time and Snore Score, a specific score obtained by the SnoreLab app. Data obtained from polygraphy were: starting/ending time of monitoring, time in bed, total snoring time, snore index (SI), snore index obstructive (SI obstructive) and apnea-hypopnea-index (AHI). For different thresholds of percentage snoring per night, accuracy, sensitivity, specificity, positive and negative predictive values were calculated. Comparison of methods was undertaken by Spearman-Rho correlations and Bland-Altman plots. The SnoreLab app provides acceptable accuracy values measuring snoring >50% per night: 94.7% accuracy, 100% sensitivity, 94.1% specificity, 66.6% positive prediction value and 100% negative prediction value. Best agreement between both methods was achieved in comparing the sum of loud and epic snoring ratios obtained by the SnoreLab app with the total snoring ratio measured by polygraphy. Obstructive events could not be detected by the SnoreLab app. Compared to polygraphy, the SnoreLab app provides acceptable accuracy values regarding the measurement of especially heavy snoring.

3D-analysis of unwanted tooth movements despite bonded orthodontic retainers: a pilot study.

BACKGROUND: Recently, reports of unwanted tooth movements despite intact orthodontic bonded retainers have increased. These movements are not subject to relapse but are classified as a new developed malocclusion. The aims of the present pilot study were to analyze the prevalence of unwanted tooth movements despite intact bonded cuspid-to-cuspid retainers and to identify possible predisposing factors. MATERIALS AND METHODS: Plaster casts of all patients finishing orthodontic treatment during three consecutive years were assessed before treatment (T0), after multibracket appliance debonding (T1) and after two years of retention (T2). After multibracket appliance treatment, all patients received a cuspid-to-cuspid flexible spiral wire retainer bonded to each tooth of the retained segment in the upper and lower jaw. The study group (SG) consisted of 44 patients (16 male, 28 female) with tooth movements (T1-T2) of the retained segment despite intact bonded cuspid-to-cuspid retainer and the control group (CG) of 43 patients (19 male, 24 female) without unwanted tooth movements. The casts of the SG were digitized, superimposed and measured. Using the Chi-square test, Fisher´s exact test and Mann-Whitney-U-test (p < 0.05), mandibular plane angle, incisor proclination, oral dysfunctions or habits (T0) and intercanine distance, overjet and interincisal relationship (T0, T1, T2) were compared between SG and CG. RESULTS: The prevalence of patients with unwanted tooth movements in one or both jaws was 27.0%. Maxillary retainers were affected more often (20.9%) than mandibular retainers (14.1%). The median amount of tooth movements was 0 to 0.66 mm with large interindividual variations. Oral dysfunctions or habits at T0, such as a lack of interincisal contact at all time points, were associated with unwanted tooth movements. CONCLUSION: Unwanted tooth movements occurred more often with maxillary than mandibular retainers. Patients with oral dysfunctions/habits and without interincisal contact had a higher prevalence of unwanted tooth movements.

Digital versus Conventional Impression Taking Focusing on Interdental Areas: A Clinical Trial.

Due to the high prevalence of periodontitis, dentists have to face a larger group of patients with periodontally compromised dentitions (PCDs) characterized by pathologic tooth migration and malocclusion. Impression taking in these patients is challenging due to several undercuts and extensive interdental areas (IAs). The aim of this clinical trial was to analyze the ability of analog and digital impression techniques to display the IAs in PCDs. The upper and the lower jaws of 30 patients (n = 60, age: 48-87 years) were investigated with one conventional impression (CVI) using polyvinyl siloxane and four digital impressions with intraoral scanners (IOSs), namely True Definition (TRU), Primescan (PRI), CS 3600 (CAR), and TRIOS 3 (TIO). The gypsum models of the CVIs were digitalized using a laboratory scanner. Subsequently, the percentage of the displayed IAs in relation to the absolute IAs was calculated for the five impression techniques in a three-dimensional measuring software. Significant differences were observed among the impression techniques (except between PRI and CAR, p-value < 0.05). TRU displayed the highest percentage of IAs, followed by PRI, CAR, TIO, and CVI. The results indicated that the IOSs are superior to CVI regarding the ability to display the IAs in PCDs.

Comparison of Quantitative light-induced fluorescence-digital (QLF-D) images and images of disclosed plaque for planimetric quantification of dental plaque in multibracket appliance patients.

The purpose of the present cross-sectional clinical study was to check the ability of plaque detection and quantification by QLF-D against conventional digital photographs of disclosed plaque in multibracket appliance (MB) patients. 20 patients were included according to the following criteria: (1) upper and lower jaw treated by MB appliance, (2) patients being 16 years of age or older, (3) all central and lateral incisors as well as canines in situ, (4) absence of developmental defects, carious lesions, surface fillings, prosthetic restorations or recessions greater than 1/3 of root length in central/lateral incisors and canines as well as (5) declaration of consent. QLF-D and conventional photographs were analyzed planimetrically regarding plaque coverage on buccal and oral surfaces of central/lateral incisors and canines. The conventional photographs of stained plaque served as gold standard. On average, in QLF-D pictures 20.7% ± 17.4 of the tooth surfaces were covered with plaque, while the conventional photographs of disclosed plaque presented a mean plaque-covered area of 36.2% ± 23.5. The Bland-Altman plot for both imaging modalities showed a very large inconsistent scattering with both negative and positive deviations. The method discrepancy increased with increasing plaque coverage, thus indicating a systematic method error. On average, the deviation of the methods from the optimal line of accordance was -15.5%. In patients wearing MB appliances, there was no clinical significant agreement regarding the plaque-covered tooth surface depicted by QLF-D respectively conventional images of disclosed plaque. Due to the large method discrepancy, QLF-D is currently not reliable for precise plaque quantification in MB patients.

In vitro comparison of analog versus digital impressions of the periodontally compromised dentition focused on interdental areas.

AIM: For orthodontic aligner treatment, excellent full-arch impressions with correctly displayed interdental areas (IAs) are required. To analyze the ability of impression taking of the IAs in periodontally compromised dentitions, two intraoral scanning systems and one conventional impression technique were investigated in vitro under standardized testing conditions. MATERIALS AND METHODS: A total of 60 impressions of the maxilla and mandible were taken from a periodontally compromised test model (A-PB) with three different techniques (n = 20): One conventional impression (EXA'lence) (CVI) and two digital impressions with the intraoral scanners Trios III (3Shape) (TIO) and True Definition (3M ESPE) (TRU). Standard tessellation language (STL) datasets were generated for TIO and TRU, whereas type IV dental stone casts were manufactured for CVI. The casts were then digitized with a laboratory scanner (ATOS). The percentage of displayed IAs in relation to the complete IA was calculated for each IA using evaluation software (GOM Inspect). Finally, the data were subjected to the median test. RESULT: TRU showed a significantly higher percentage of displayed IAs compared with the other two methods (P < 0.05). Only a few IAs were shown in CVI. TIO showed significantly better results compared with CVI, although the results were not as good as those of TRU. CONCLUSION: Within the limitations of this in vitro study, intraoral scanners - and especially the one based on active wavefront sampling (AWS) technology (as for TRU) - can be recommended for the reproduction of wide IAs (undercuts) in periodontally compromised patients.

Effect of orthognathic surgery on profile esthetics in Class II:1 malocclusions.

OBJECTIVES: To measure the effect of orthognathic surgery on Class II:1 profile silhouette esthetics and to identify pretreatment parameters and thresholds for consistent esthetic improvement. METHODS: Pre- and posttreatment black profile silhouettes of 20 patients with Class II:1 malocclusion who had received combined orthodontic/orthognathic treatment were evaluated retrospectively by 20 European orthodontists and laypeople each using a visual analogue scale (VAS). A variety of pretreatment skeletal and facial angles were measured cephalometrically and on the silhouette profiles. Descriptive statistics and Pearson's correlation coefficients were calculated. RESULTS: The population showed a mean VAS improvement of 12.6%. VAS changes were significantly and directly related to pretreatment ANB in all evaluator groups (r = 0.48-0.59), whereas the interrelation with the degree of pretreatment profile convexity angle was less clear and statistically significant for the orthodontic evaluators only (r = -0.34 to -0.51). The highest correlation coefficients in all evaluator groups were seen for the relationship with pretreatment VAS scores (r = -0.64 to -0.73). CONCLUSION: The lower the pretreatment VAS score and the profile convexity angles or the larger the pretreatment ANB angles were, the more the VAS improved. Pretreatment thresholds for consistent improvements were as follows: VAS score < 20 mm, ANB > 8°, and profile angle ≤ 155°.

Excellent versus unacceptable orthodontic results: influencing factors.

AIM: To retrospectively compare patients with excellent and unacceptable orthodontic treatment results with respect to possible prognostic factors. MATERIAL AND METHODS: All patients, who completed treatment at the Department of Orthodontics of the Justus-Liebig-University Giessen, Germany between 1993 and 2009 with an excellent or unacceptable outcome according to the Ahlgren index. Possibly influencing factors regarding case history, treatment, cephalometrics, and plaster casts were analyzed. Furthermore, PAR index pre- and post-treatment was compared. The explorative statistical analysis was performed using Fishers Exact test, Chi-square test, and Mann-Whitney U-test. RESULTS: Out of 1653 patients, treatment outcome was excellent in 226 (13.7 per cent) and inacceptable in 56 (3.4 per cent) patients. For the remaining cases, a good or acceptable outcome was assessed. Pretreatment PAR scores showed no difference between the excellent and unacceptable group. The following factors were significantly more common in the unacceptable group: male predominance (P = 0.009), occurrence of general diseases (P = 0.003), habits (P < 0.001), prolonged active appliance treatment duration (P = 0.014), negative cooperation (P < 0.001), denial of recommended appliance or premature removal of appliances (P < 0.001), decreased pretreatment overbite (P = 0.005), and hyperdivergent jaw base relationships (P = 0.005). CONCLUSION: Patient cooperation remains the outstanding parameter determining treatment success. A proportionally higher frequency of unacceptable treatment results must be expected in patients with open bite configurations (skeletally, dentally, and functionally).

Oral microbiota carriage in patients with multibracket appliance in relation to the quality of oral hygiene.

BACKGROUND: The present study aimed to investigate the prevalence of oral microbiota (Candida species (spp.), Streptococcus mutans, and Lactobacilli) in patients with multibracket (MB) appliances in relation to the quality of oral hygiene. Saliva and plaque samples were collected from three groups of 25 patients each (good oral hygiene (GOH), poor oral hygiene (POH), and poor oral hygiene with white spot lesions (POH/WSL)). Counts of colony forming units (CFU) of the investigated oral microbiota were compared using Chi-square and Mann-Whitney U tests. RESULTS: Both saliva and plaque samples showed a high prevalence of Candida spp. in all patients (saliva: 73.4 %, plaque: 60.9 %). The main Candida species was C. albicans. The salivary CFU of Candida spp. in the GOH group was significantly lower than that in the POH group (p = 0.045) and POH/WSL group (p = 0.011). S. mutans was found in the saliva and plaque samples of all patients. Lactobacilli were found in the saliva samples of all patients and in 90.7 % of the plaque samples. In the saliva samples, the CFU of Lactobacilli were more numerous in the POH and POH/WSL groups than in the GOH group (p = 0.047). CONCLUSIONS: The investigated sample of patients showed a high carriage of oral Candida spp. Patients with WSL formation during MB appliance treatment exhibited higher counts of Candida and Lactobacilli compared with patients with good oral hygiene. Independent of oral hygiene quality, S. mutans was detected in all patients.