Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition.

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear aligner) therapy, particularly when compared to the use of traditional fixed appliances. This becomes particularly significant in cases involving anteroposterior, vertical, and transverse corrections, where precise comparisons are of paramount importance. To address these inquiries, this study introduces a meticulously devised protocol, placing a primary emphasis on digitally superimposing the movement of maxillary posterior teeth to facilitate accurate analysis. The sample included 25 patients who had completed their first series of Invisalign (clear) aligners. Four maxillary digital models (pre-treatment, post-treatment, ClinCheck-initial, and final models) were digitally superimposed using the palate rugae and dentitions as stable references. A software combination was used for model superimposition and tooth segmentation. Transformation matrices then expressed the differences between the achieved and predicted tooth positions. Thresholds for clinically relevant differences were at ±0.25 mm for linear displacement and ±2° for rotation. Differences were assessed using Hotelling's T-squared tests with Bonferroni correction. The mean differences in rotation (2.036° ± 4.217°) and torque (-2.913° ± 3.263°) were significant statistically and clinically, with p-values of 0.023 and 0.0003 respectively. De-rotation of premolars and torque control for all posterior teeth were less predictable. All mean differences for the linear measurements were statistically and clinically insignificant, except that the first molars seemed slightly (0.256 mm) more intruded than their predicted position. The clear aligner system appears to meet its prediction for most translational tooth movements and mesial-distal tipping in maxillary posterior teeth for non-extraction cases with mild to moderate malocclusions.

Craniofacial features of adult obese obstructive sleep apnoea patients in relation to the obesity onset - A pilot study.

INTRODUCTION: Obesity and craniofacial structures are aetiologies of obstructive sleep apnoea (OSA). The effect of obesity onset on the craniofacial development and growth of obese OSA subjects has been suggested, but supporting data were lacking. This study aimed to assess the craniofacial features of adult obese OSA patients in relation to their obesity onset. MATERIALS AND METHODS: A total of 62 adult OSA patients were included in the study, consisting of 12 early-onset (i.e. before puberty), 21 late-onset (i.e. after puberty) and 29 non-obese. All participants underwent a sleep study and cephalometric radiograph. Cephalometric analysis was conducted to measure the craniofacial features among the groups. RESULTS: The early obesity onset group (n = 12) showed a more prognathic mandible, longer lower facial height, protrusive incisors, a more caudal position of the hyoid bone and a wider lower airway. The late-onset group (n = 21) had more proclined and protrusive upper incisors, a shallower overbite, a more inferiorly positioned hyoid bone and an obtuse craniocervical angle. The overall obese group showed a combination of the findings above, plus a shorter soft palate and shorter airway length. There was no significant difference between early and late obesity onset groups. However, the early group showed a tendency for a shallower or decreased mandibular plane angle and deeper overbite. CONCLUSIONS: The current pilot study had many limitations but holds important information as a hypothesis generator. Craniofacial features of OSA patients with different obesity onset showed discrepancies and were distinguished from non-obese controls. Adult OSA patients with an early obesity onset showed a tendency for a more hypodivergent growth pattern than those with a late obesity onset.

A new method assessing predicted and achieved mandibular tooth movement in adults treated with clear aligners using CBCT and individual crown superimposition.

The purpose of this study was to demonstrate a new method for quantifying the difference between predicted and achieved tooth movement with Invisalign using stable three-dimensional (3D) mandibular landmarks and dental superimposition. Cone-beam computed tomography (CBCT) scans before (T1) and after (T2) the first series of aligners, their corresponding digital models (ClinCheck initial of the first series as T1 and ClinCheck initial of the refinement series as T2), and the ClinCheck final model of the first series as the predicted were obtained from 5 patients treated with non-extraction Invisalign therapy. After segmentation of the mandible and its dentition, T1 and T2 CBCTs were superimposed on stable anatomic structures (Pogonion and bilateral mental foramen) along with the pre-registered ClinCheck models. The 3D prediction differences between the predicted and achieved tooth position for 70 teeth with four types (incisor, canine, premolar and molar) were measured using a combination of software. The method employed in this study was tested to be reliable and repeatable with a very high intraclass correlation coefficient (ICC) for both intra- and inter-examiner reliability. Premolar Phi (rotation), Incisor Psi (mesiodistal angulation), and Molar Y (mesiodistal translation) showed a significant prediction difference (P < 0.05), which is also clinically relevant. The method involving CBCT and individual crown superimposition to measure the 3D positional changes in the mandibular dentition is a robust and novel one. While, our finding in terms of the predictability of Invisalign treatment in the mandibular dentition mainly served as a crude, cursory examination, which warrants further and more rigorous investigations. With this novel methodology, it is possible to measure any amount of 3D tooth position difference in the mandibular dentition either between the simulated and the actual or with treatment and/or growth. Deliberate use of overcorrection of which specific type of tooth movement with clear aligner treatment and to what extent, might be possible with future studies.

Theory-Guided Remote Cooperative Learning-Based Preventive Dental Education as Part of the School Curriculum.

BACKGROUND: Oral health is fundamental to overall well-being. As teens are at high risk for tooth decay, we require a unique approach to motivate them to maintain oral health. METHODS: Sixty-four adolescents (10-13 years) were recruited from 2 schools. Oral health education was based on cooperative learning guided by the social determination theory (SDT) principles. Students' oral health knowledge and oral self-care skills were assessed at baseline (before education), 3 weeks, and 6 months after the education. RESULTS: Complete data were available for 51 students (follow-up rate 79.7%). There were significant (p < 0.001) changes in the mean (SD) toothbrushing score from 10.1 (±6.3) (baseline) to 26.5 (±6.0) (follow-up 1) and to 28.1 (±5.3) (follow-up 2). The mean (SD) tooth brushing time significantly (p < 0.001) increased from the baseline of 84.0 (±43.5) to the first follow-up to 107.0 (±39.8) and to 102.3 (±33.1) at the second follow-up. The mean (SD) diet knowledge scores significantly (p < 0.001) increased from 8.2 (±2.1) at the baseline to 10.2 (±2.7) at the first follow-up and remained the same at the second follow-up. CONCLUSION: Social determination theory-guided cooperative learning was efficient in improving student oral health-related knowledge and oral self-care skills, and this improvement was maintained for 6 months after the discontinued education.

Accuracy of intraoral scan images in full arch with orthodontic brackets: a retrospective in vivo study.

OBJECTIVES: The purpose of this retrospective study was to evaluate the accuracy of intraoral scan (IOS) images in the maxillary and mandibular arches with orthodontic brackets. MATERIAL AND METHODS: From digital impressions of 140 patients who underwent orthodontic treatment, consecutive IOS images were selected based on standardized inclusion criteria: Two pre-orthodontic IOS images (IOS1 and IOS2) of permanent dentition with fully erupted second molars and IOS images obtained immediately after orthodontic bracket bonding (IOSb). Superimpositions were performed to evaluate the reproducibility of repeated IOS images. Accuracy of IOSb images was analyzed by comparing the average surface errors between IOS1c and IOS2c images, which were IOS images cut based on the same region of the interest as between IOS1 and IOSb images. RESULTS: A total of 84 IOS images was analyzed. The average surface errors between IOS1 and IOS2 images were 57 ± 8 µm and 59 ± 14 µm in the maxillary and mandibular arch, respectively, and their reliability was almost perfect. The average errors between IOSb and IOS1c images exhibited an increase, which measured 97 ± 28 µm in the maxillary arch and 95 ± 29 µm in the mandibular arch. These surface deviations between IOSb and IOS1c images were significantly larger in each region as well as entire dentition (P < 0.001) compared to those between IOS1c and IOS2c images. CONCLUSIONS: The average surface errors of the scans with brackets showed increased values compared with those without brackets. This suggests that orthodontic brackets could affect the trueness of intraoral scan images. CLINICAL RELEVANCE: It is necessary for clinicians to consider the effect of brackets on digital impression when using IOS images in orthodontic patients.

Outcomes of orthodontic treatment performed by individual orthodontists vs 2 orthodontists collaborating on treatment.

INTRODUCTION: One factor that can affect treatment outcomes is the treatment provider, and this factor has not been extensively studied. This research aimed to evaluate orthodontic treatment quality, length, and efficiency when 2 orthodontists collaborated on treatment, compared with the treatment provided solely by either orthodontist. METHODS: A total of 150 consecutively treated subjects were divided into 3 equal groups based on the treating clinician. Patients in group A were treated by orthodontist A, group B by orthodontist B, and group C by both orthodontists in collaboration. The Peer Assessment Rating (PAR), Index of Complexity, Outcome, and Need (ICON), American Board of Orthodontics-Discrepancy Index, and American Board of Orthodontics-Cast and Radiographic Evaluation were used to assess the pretreatment and posttreatment status. Patient age, gender, type of malocclusion, extraction treatment, orthognathic surgery, treatment length, number of visits, and treatment efficiency index were assessed. RESULTS: Posttreatment PAR and ICON indices showed excellent results in all 3 groups. American Board of Orthodontics-Cast and Radiographic Evaluation was significantly higher in group C (25.3 points) than in group A (21.5 points) or group B (22.0 points) (P = 0.014). Patients in group A had significantly shorter treatment time (23 months) than those in either group B or C (26 months) (P = 0.011). Patients in group C required more appointments (27 visits) than those in either group A or B (23 and 25 visits, respectively). The treatment efficiency index showed no statistically significant difference among the 3 groups. CONCLUSIONS: There was no difference in treatment quality among the 3 groups, as assessed by the PAR index and ICON. Jointly treated cases required 2 to 4 more visits and had higher American Board of Orthodontics-Cast and Radiograph Evaluation scores than those treated by either orthodontist. Complex cases required 6 to 7 more months when they were treated collaboratively.

Mandibular dental changes following serial and late extraction of mandibular second premolars.

OBJECTIVES: To determine changes in occlusal curves and dental tipping occurring from mandibular second premolar serial extraction, early extraction of deciduous mandibular second molars with missing second premolars, and late second premolar extraction compared with untreated controls. MATERIALS AND METHODS: Information was collected from 85 subjects at three time points: T0, prior to serial extraction; T1, after serial extraction and drift prior to orthodontic treatment, and pretreatment for the late premolar extraction patients; and T2, posttreatment. Untreated age- and gender-matched controls were used for comparison. Three occlusal curves were measured on digitized mandibular casts, and dental tipping was assessed using lateral cephalograms. RESULTS: At T0, there were no significant differences among groups. At T1, there was significant steepening of Monson's sphere and the curve of Wilson between early and late extraction and control groups. At T2, the differences in Monson's sphere and the curve of Wilson were fully corrected. At T1, there were significant differences in the tipping of mandibular 6's, 4's, and 3's between the early extraction groups compared with the late extraction and control groups. At T2, these differences in tipping were fully corrected. There were no differences in mandibular incisor tipping between groups at T1 or T2. CONCLUSIONS: Serial extraction produced steeper occlusal curves and significant tipping of mandibular first molars, first premolars, and canines after extraction and physiologic drift (T1). Accentuated occlusal curves and tooth tipping were fully corrected following orthodontic treatment (T2). Mandibular incisor position was unchanged by serial or late second premolar extraction.

Fistula in Cleft Lip and Palate Patients-A Systematic Scoping Review.

AIMS: (1) Assess the level of available evidence regarding fistula occurrence in cleft lip and palate patients, (2) identify main research areas in the original studies, (3) evaluate the quality of original studies, and (4) summarize the evidence. METHODS: Two independent researchers searched the Cochrane Database of Systematic Reviews, Medline, Web of Knowledge, Web of Science and EMBASE, the Grey literature, and the reference lists of main references. The level of evidence was assessed based on study design and according to the Hierarchy of Evidence. The quality assessment was done using the adapted Consolidated Standards of Reporting Trials and Strengthening the Reporting of Observational Studies in Epidemiology checklists and a validity scoring system. Main findings were summarized, and fistula rates were compared between early and more recent articles, also between high-quality and low-quality studies. RESULTS: The systematic search and relevance assessment identified a total of 127 sources of evidence. The overall level of evidence was weak because it was dominated by small studies (<30 subjects), retrospective cohort studies, and case series. Main research areas were either: (1) focused on surgeries or (2) focused on risk determinants associated with fistula occurrence. Recent reports were of higher quality than the older ones, but the overall quality in the majority of reports was low. Knowledge synthesis demonstrated a wide range of rates for primary fistula (0-78%). No significant difference was found in the fistula rates of older studies compared with more recent studies or among different quality studies. Multiple risk determinants were studied and age at surgery, surgeon's experience, type and severity of cleft were the most frequently examined risk determinants. However, findings concerning different risk determinants and fistula occurrence were not consistent. CONCLUSIONS: The research mainly focused on surgeries and fistula-related risk determinants. The available evidence was low level and of poor quality. No consistent pattern between fistula occurrence and any of the risk determinants could be detected. Reported fistula rates did not differ significantly when comparing older studies with more recent studies or when high-quality studies were compared with low-quality studies.

Mandibular changes secondary to serial extractions compared with late premolar extractions and controls.

INTRODUCTION: Variations in treatment times for serial extraction and late premolar extraction patients may be due to differences in the time needed to flatten the occlusal curves. In this study, we compared tooth tipping and occlusal curves in patients treated by serial extractions or late premolar extractions with untreated controls. METHODS: Mandibular dental casts and cephalometric radiographs were collected from 90 subjects (30 Class I control subjects, 30 patients with serial extractions, and 30 with late premolar extractions) at 3 time points: T0, baseline for the controls and serial extraction patients; T1, after natural drift and preorthodontics for the controls and the serial extraction patients, and pretreatment for the late premolar extraction patients; and T2, after comprehensive orthodontic treatment for the serial extraction and the late premolar extraction groups. The long axes of the central incisor, canine, and first molar to the palatal plane were measured on digitized headfilms to determine the direction and the amount of tipping between the time points. Three occlusal curves were measured by sphere fitting cusp-tip landmarks on digitized mandibular casts. RESULTS: From T0 to T1, incisors and canines in the patients with serial extractions tipped distally. Molars at T1 in the patients with serial extractions were tipped forward more than in the late premolar extraction patients and the controls. From T1 to T2, canines and molars in the patients with serial extractions were uprighted. CONCLUSIONS: Serial extractions produce steeper occlusal curves and distal tipping of the incisors and canines after drift (T1). Posttreatment (T2) occlusal curves in the patients with serial extractions are steeper than in the late premolar extraction patients and controls (except for the curve of Spee). After the serial extractions, orthodontic treatment included incisor and canine proclination, with molar uprighting and occlusal curve flattening.

Orthodontic treatment considerations for a patient with erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) is an inherited blood disorder in which formation of the heme group of hemoglobin is defective. Specifically, a deficiency of the enzyme ferrochelatase leads to the accumulation of protoporphyrin, resulting in often painful photosensitivity of the skin and tissues. The prevalence of EPP is estimated at 1:75,000 to 1:200,000. Photosensitivity is exhibited upon exposure to light with specific wavelengths through the creation of reactive oxygen products (oxidants), activation of the complement system, and mast cell degranulation. The aim of this article is to report the orthodontic treatment of an 11-year-old boy with EPP, a Class III skeletal relationship, and an anterior crossbite. Orthodontic treatment established normal overbite and overjet. Short-term periodontal and dental tissue responses to treatment were noted. Extra care was needed when collecting photographic and radiographic records for this patient and during some treatment procedures to avoid causing a photosensitive reaction of the skin or oral mucosa.

The development, implementation, utilization and outcomes of a comprehensive dental program for older adults residing in long-term care facilities.

This paper documents the experience of the University of British Columbia's Geriatric Dentistry Program (GDP) with emphasis on the dental treatment needs of patients during its first year of operation. The GDP provided access to dental care for residents of longterm care facilities, education for hospital staff concerning daily mouth care, education of dental students and an opportunity for research. The first year of clinical activity saw a small, yet significant, improvement in oral health for residents using the dental services. We hope that the outcomes of this new dental program for long-term care facilities will encourage dentists to provide care for this vulnerable population.