A novel method quantifying caries following orthodontic treatment

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19–25, 1994, levels 0–3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1–3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20–100% before and 52.3% after MB. The incidence in the UJ (71–79%) as well as the LJ (64–76%) was highest for the first and second premolars and lowest for LJ incisors (22–35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.

Area and Volume of Remaining Cement and Enamel after Removal and Polishing of Buccal or Lingual Multibracket Appliances

The aim of the present study was to compare the area and volume of remaining cement after lingual and buccal multibracket appliance debonding. Further, the area and volume of cement remaining and the area and volume of enamel were also analyzed using a morphometric digital measurement technique. Ten buccal and 10 lingual multibracket appliances were cemented in 20 extracted teeth embedded into an epoxy resin model simulating a dental arch. The models were scanned before bonding the lingual and buccal multibracket appliances, after debonding the lingual and buccal multibracket appliances, and after polishing the remaining cement. Afterwards, the standard tessellation language (STL) digital files were aligned, segmented, and realigned by using engineer morphometry software. A comparative analysis was performed using Student’s t test statistical analysis. Lingual appliances showed statistically significantly (p < 0.001) less area (7.07 ± 4.85 mm2) and volume (0.87 ± 1.34 mm3) of remaining cement than the area (21.99 ± 4.18 mm2) and volume (p = 0.002) (3.48 ± 0.96 mm3) of buccal appliances. Moreover, lingual appliances showed statistically significantly (p = 0.001) less area (4.48 ± 3.08 mm2) and volume (0.13 ± 0.15 mm3) of remaining cement after polishing than the area (12.22 ± 5.98 mm2) and volume (p = 0.004) (0.70 ± 0.56 mm3) of buccal appliances. Lingual multibracket appliance therapy leads to less area and volume of cement remaining after multibracket appliance debonding and less area and volume of cement remaining after cement polishing than buccal multibracket appliance therapy; however, the area and volume of enamel removed after cement polishing were similar between both lingual and buccal multibracket appliance therapies.

A Repeatable and Reproducible Digital Method to Quantify the Cement Excess and Enamel Loss after Debonding Lingual Multibracket Appliance Therapy

The aim of the present study is to present a repeatable, reproductible, and accurate morphometric measurement method for measuring and quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances. Ten conventional lingual brackets were cemented in 10 extracted teeth embedded into an epoxy resin model simulating a dental arch. This model was scanned before and after bonding the lingual brackets, after debonding, and after polishing the surfaces. We also performed a Micro-Computed Tomography scan of the lingual brackets used. Afterward, the standard tessellation language (STL) digital file was aligned, each tooth was segmented individually, and the file was re-aligned using engineer morphometry software. Inter-operator and intra-operator comparative analyses were performed using the ANOVA test, and the repeatability and reproducibility of the morphometric measurement technique were analyzed using Gage R&R statistical analysis. Repeatability showed 0.07% and 0.16% variability associated with the area and volume measures, respectively, while reproducibility showed 0.00% variability associated with the area and volume measures, respectively. In conclusion, the morphometric measurement technique is a repeatable, reproductible, and accurate morphometric measurement method for quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances.

Herbst–multibracket appliance treatment: is there an association between lower incisor position changes and the development of labial gingival recessions?

Purpose To assess a potential association between lower incisor (LI) position changes during Herbst–multibracket appliance (Herbst–MBA) treatment and the development of labial gingival recessions (LGR). Methods All class II patients (Department of Orthodontics, University of Giessen, Giessen, Germany) who had undergone Herbst–MBA treatment until 2015 with study models and lateral cephalograms available from before (T0) and after treatment plus ≥24 months of retention (T3) were included (n = 259). Lateral cephalograms were evaluated regarding LI position changes: iiL/ML (angle between LI long axis and mandibular plane [MP]), ii-MLPg (distance between LI incisal edge and a line perpendicular to MP through pogonion), apex-MLPg (distance between LI apex and a line perpendicular to MP through pogonion), ii-MLii (distance between LI incisal edge and MP on a line perpendicular to MP through incisal edge). Using study models the distance between the cementoenamel junction and the deepest point of the gingival margin was defined as LGR. Results The following cephalometric mean changes were recorded (T0–T3): iiL/ML +5.9 ± 5.76° (p = 0.929), ii-MLPg −0.2 ± 0.25 mm (p = 0.430), apex-MLPg +0.1 ± 0.32 mm (p = 0.363), ii-MLii +0.1 ± 0.36 mm (p = 0.206). The mean increase of LGR magnitude measured on the study models was 0.1 ± 0.35 mm. However, no association with the cephalometric LI position changes was found (|R| ≤ 0.2). Conclusion There is no association between the amount of LI position changes and the development of LGR during Herbst–MBA treatment plus retention. Nevertheless, individual predisposition or excessive treatment changes and extraordinary treatment approaches, respectively, might still lead to development of LGR.

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.

Outcome quality of Class II division 1 Herbst-multibracket appliance treatment: influence of pretreatment Class II severity and skeletal maturity

Summary Background No reliable predictive factors for treatment (Tx) success and outcome quality in Class II:1 Tx have been identified yet. Objective To assess the influence of pre-Tx Class II severity and skeletal maturity on outcome quality after Herbst-multibracket appliance (MBA) Tx. Subjects and methods All Class II:1 patients who completed Herbst-MBA Tx between 1986 and 2014 at University of Giessen, Germany. Pre-Tx (T0), post-Tx (T1), and (if available) post-retention (≥24 months; T2) study casts were evaluated using the Peer Assessment Rating (PAR) index and the Ahlgren scale. Three occlusal severity (mild, moderate, and severe) and four skeletal maturity (pre-peak, peak, post-peak, and adult) subgroup categories were defined. Results Four hundred eight-five patients (age at T0: 14.4 ± 3.2 years) could be evaluated; post-retention (T3) data were available for 230 patients. For the total sample, the median PAR score was 32.4 ± 8.85 at T0, 8.0 ± 4.52 at T1, and 8.8 ± 5.11 at T2. Very low correlations between the subgroup categories (occlusal severity/skeletal maturity) and PAR-score reduction were detected both during Tx (r = 0.12/r = 0.05) and the total observation period (r = 0.17/r = 0.03). The overall outcome quality according to Ahlgren was: 17.0% excellent, 34.8% good, 43.8% acceptable, 2.2% unacceptable, and 2.2% not assessable. The association with the subgroup categories was: p = 0.019 (occlusal severity)/p = 0.820 (skeletal maturity). Limitations Retrospective study design with follow-up data was not available from all subjects and no data from untreated controls. Tx was performed by several physicians using different kind of MBAs. Conclusion Class II:1 Herbst-MBA Tx is an effective and successful Tx approach irrespective of pre-Tx skeletal maturity but dependent—to a certain extent—on Class II severity. Thus, when considering a Herbst appliance for Class II correction, neither of the two variables should considerably limit the indication.

A New Method for Quantifying Labial White Spot Lesions

Aims: This study aimed to evaluate the prevalence as well as incidence of White Spot Lesions (WSL) before and after labial multibracket appliance (MB) therapy. The goal was also to determine the intensity of WSL based on the Enamel Decalcification Index (EDI) by Banks & Richmond (1994). Moreover, this study investigated the scope of WSL by using a newly-developed evaluation tool. Materials & methods: Digital photographs of 121 patients (63 ♂, 58 ♀) with labial metal brackets were analyzed retrospectively before and after MB therapy. The patients were 12.5±2.1 years old. The treatment took 3.1±1.4 years. Adult patients as well as patients with structural or restaurative modifications were excluded from the study. All patients received standardized prophylactic instructions. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated by using the Enamel Decalcification Index (EDI) by Banks & Richmond (1994, levels 0-3) and a specially developed scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Results: Before MB, 69.4% of the patients had WSL. After MB therapy, 97.5% of the patients presented at least one WSL. The incidence amounted to 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1-3. After MB, 51.8% of the TS featured WSL. Before and after MB, the prevalence for WSL was higher on UJ and LJ canine teeth and premolars than on incisors. 18.2% of the TS showed a WSL to the extent of ≥ 20-100% before MB and 52.3% after MB. The majority (40.8%) of the newly-developed WSL concerned ≥ 40% of TS. The incidence in the UJ was highest for the first and second premolars (71-79%), followed by the lateral incisors (61-63%). In the LJ, the incidence was highest for the second and first premolars (64-76%) and lowest for incisors (22-35%). The logistic regression showed a statistically increased risk to develop WSL after MB for lateral incisors, UJ canine teeth, and for UJ and LJ premolars in male patients. The probability for developing a new distal WSL is higher than developing gingival, mesial, and occlusal WSL. Conclusion: Labial MB therapy is found to drastically increase the risk of developing WSL. Particularly, premolars and canine teeth showed an increased prevalence. In using the specially developed evaluation index, we were able to verify through simple handling and intra-rater reliability a concise quantification of the extent of labial WSL.

Multiple Dental Inclusion in Monozygotic Twins with Congenital Visual Impairment

The study presents two monozygotic twins (MZ) with multiple impacted teeth, affecting the upper canines and lower second molars, as well as congenital aniridia. The clinical aspect of the upper canines is peculiar because of the different positions—palatal in one and buccal in the other twin. Studies reporting different scenarios of impaction in monozygotic twins can contribute more data to the debate on tooth eruption aetiology and more so in this case because of the association with a genetic panocular disease. Patients’ Concerns. The patients were referred by a general dentist, who diagnosed the presence of multiple inclusions. Diagnostic Study. Both patients showed severe malocclusion, classified as grade 5 of the Index of Orthodontic Treatment Need (IOTN). The MZ showed class I malocclusion, upper and lower crowding, and impacted lower right and left second molars. A Dentascan was prescribed for the canine impaction. The impaction of the upper canine was palatal of 2.3 in one of the MZ and buccal of 1.3 in the other one. The same altered pattern of eruption of the lower second molars was identified in both twins. The proposed treatment plan contemplated orthodontic surgical recovery of the impacted elements, followed by orthodontic treatment with multibracket appliance after the extraction of the first four premolars, given the crowding entity. The use of a retraction spring action was chosen for the recovery of the lower second molars. Many aspects of the possible genetic aetiology of tooth impaction are still under discussion. The study of diseases in twins offers decisive information. Finally, the possibility that alterations in the eruptive pattern of the dental elements may be associated with other congenital problems broadens the range of investigations related to the possible aetiological causes of the inclusions in humans.

Novel Digital Technique to Quantify the Area and Volume of Cement Remaining and Enamel Removed after Fixed Multibracket Appliance Therapy Debonding: An In Vitro Study

The aim of this study was to construct a novel, repeatable, reproducible, and accurate measurement protocol for the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere fixed multibracket appliances. A total of 30 brackets were cemented and removed with over 30 extracted teeth embedded into three experimental models of epoxy resin. The models were scanned before and after bracket placement, bracket debonding, and polishing the remaining cement. The brackets were submitted to micro-computed tomography. The standard tessellation language digital files were aligned, segmented, and re-aligned using geomorphometric software. The digital measurement technique accuracy, repeatability, and reproducibility were analyzed using Gage R&R statistical analysis. The variability attributable to the area and volume measurement techniques of the total variability of the samples was 0.70% and 0.11% for repeatability, respectively, and 0.79% and 0.01% for reproducibility, respectively. The re-alignment procedure is a repeatable, reproducible, and accurate technique that can be used to measure the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere the fixed multibracket appliance.