Volume 38 (2022): Issue 2 (July 2022)

The management of a Class III malocclusion in the mixed dentition presents with many challenges, in particular, the post-treatment growth-related changes which can continue into adulthood. This case report describes the multidisciplinary management of a 9-year-old female using titanium dental implants, rapid maxillary expansion and a Delaire facemask. Pre-treatment, post-treatment and long-term follow-up records of the patient are presented.

The ectopic eruption path of a permanent molar can cause incomplete emergence through interference by an adjacent tooth, early loss of a primary molar, or an arch length discrepancy. It is clinically important to determine the appropriate appliance that may easily be placed for the considered application of a molar corrective force. A newly designed appliance is introduced for the distal uprighting of an ectopically erupting molar and supported by two case presentations. The current technique of using a segmental wire incorporating double-sided hooks may easily and effectively resolve this problem.

Objectives: To compare the ability of SureSmile^TM, Insignia^TM and Invisalign^TM to achieve predicted intra-arch tooth positions and further compare their objective grading scores for alignment/rotations, marginal ridge relationships and buccolingual inclination.

Materials and methods: The study was a prospective clinical trial of 145 arches from 44 females and 29 males (54 SureSmile^TM arches, 35 Insignia^TM arches, and 56 Invisalign^TM arches). All arches were treated by a non-extraction approach and had ≤7 mm of crowding and 45° of tooth rotation. The manufacturer’s recommendations were followed for each group and the final scans were acquired before refinements, rebonding, or wire bending. The virtual set-ups were superimposed on the final scans and the coordinates of 34 landmarks per arch were compared. One hundred and twenty-six end-of-participation arches were suitable for 3D printing and were compared using the American Board of Orthodontics Objective Grading Scores (OGS) for alignment/ rotations, marginal ridge relationships, and buccolingual inclination.

Results: No statistically significant differences were identified in the mean deviation between the target and achieved the position of the anterior landmarks within the treatment groups. The exception was the Suresmile group which had greater vertical discrepancies in the position of the labial CEJ. Although the mean differences between the target and achieved anterior landmark positions for all groups were under 0.5 mm, the range of maximum discrepancy was between 0.7 mm and 4.1 mm. The Insignia^TM system showed significantly greater deviation in upper posterior landmark positions in the transverse and sagittal dimensions, and lower posterior landmarks in the transverse dimension. However, this was due to the Insignia^TM initial set-ups being wider. There was no statistically significant difference between the three systems in combined intra-arch OGS. However, the Invisalign^TM system had a significantly poorer alignment/rotation score than the SureSmile^TM group. The Insignia^TM system performed better in achieving buccolingual tooth inclination compared to Suresmile^TM, and the Invisalign^TM system performed better than the Suresmile^TM system in the marginal ridge score.

Conclusions: The three systems were comparable in achieving the predicted tooth positions of the anterior teeth in non-extraction, mild-to-moderate, crowded cases. Large discrepancies requiring operator intervention were common within the three systems. Although the three systems had no statistically significant difference in overall intra-arch OGS scores, there were significant differences in the score components.

Introduction: The aim was to assess the relationship between airway morphology and surgical intervention in a cohort of patients presenting with increased body mass index (BMI) and a confirmed diagnosis of obstructive sleep apnoea (OSA). A secondary aim was to revisit the relationship between morphology and OSA severity.

Methods: A retrospective analysis was conducted of pre-operative maxillofacial 3D-CT scans of thirty-two patients with a confirmed diagnosis of OSA who received treatment from an ear nose and throat specialist (ENT). Lateral cephalograms were imported into Quick Ceph Studio (Quick Ceph Systems Inc, San Diego, CA, USA) after which linear and angular measurements of selected hard and soft tissues were obtained. 3D-CT images were loaded into the software program 3dMDVultus (3dMD) which permitted 3D visualisation of the airway. Measurements were repeated 3 times on the images of six patients after an interval of two weeks to establish the intraclass correlation coefficient (ICC) for intra-examiner accuracy and reliability. Logistic regression was applied to determine the relationships between morphology, OSA and surgical treatments.

Results: A positive correlation was found between age and the apnoea-hypopnea index (AHI). Morphological measurements of the airway did not exhibit a positive relationship with OSA severity. Posterior airway space at the level of the uvula and tongue, the length of the soft palate and position of the hyoid bone were significantly associated with BMI. No variables were found to be correlated with uvulopalatopharyngoplasty (UPPP) surgery. Notwithstanding, airway length and posterior airway space at the level of the uvula tip were significantly associated with tongue channelling.

Conclusions: Radiographic airway assessment is an invaluable and opportunistic tool for screening OSA but requires judicial use in its prescription and interpretation. There is little correlation between OSA severity and airway morphology and between surgical intervention and morphology. Additional factors need to be considered before a treatment modality is considered and is best managed in a multidisciplinary setting.

Objectives: The aim of the present study was to investigate the effect of third molars on the efficiency and biomechanics of a novel miniscrew-supported 3D^® Maxillary Bimetric Distalising Arch (3D-MBDA).

Methods: Twenty-three patients, whose third molars were either extracted at the beginning of treatment (Group 1, n =11) or retained (Group 2, n =12), were included in the study. Lateral cephalometric films and dental casts, taken at the beginning (T0) and at the end of upper molar distalisation (T1), were analysed to study the differences between groups.

Results: Crown distalisation of the first molars was similar between the groups; however, root distalisation, both at the trifurcation and apex levels, intrusion at the mesiobuccal cusp tip, and the distalisation rate were significantly higher in Group 1. The resultant tipping of the first molars in both groups was mesially-directed, unlike the usual distal tipping. The second molars distalised more, displaced less vestibularly and rotated mesiobuccally in Group 1, whereas they demonstrated a significantly higher vestibular displacement and distobuccal rotation in Group 2. The mean distalisation time was significantly shorter in Group 1 when compared to Group 2. The miniscrew success rate was 95.5% for Group 1 and 91.7% for Group 2.

Conclusion: The miniscrew-supported 3D-MBDA was found to have greater effects on root distalisation and the final inclination of the molars. The third molars were associated with limited root movement, unfavourable displacement of the second molars, as well as a slower distalisation rate. Therefore, the extraction of third molars prior to distalisation is recommended, especially when the miniscrew-supported 3D-MBDA is the appliance choice.

The present article reports the successful non-extraction orthodontic treatment using miniscrew anchorage in a patient who presented with maxillary left central incisor loss and unstable jaw movements. The chief complaints of the 23-year-old female patient were her protruding teeth and crowding of the mandibular anterior segment. The patient lost her maxillary left central incisor as a result of a traumatic injury during childhood. However, the crown was saved and attached to the adjacent teeth. The patient was diagnosed with a skeletal Class III and Angle Class III dental malocclusion. The jaw movements determined by a 6 degrees of freedom jaw movement recording system were unstable and irregular. Miniscrew anchorage was applied for distalisation of the maxillary right dentition and the mandibular dentition during non-extraction treatment. The maxillary left dentition was mesialised using miniscrew anchorage to close the space as a result of the lost maxillary left central incisor. After an active treatment duration of 36 months, the patient achieved a Class II molar relationship on the left side, a Class I on the right side, an optimal overjet and overbite, and a pleasing facial profile. Despite the asymmetric molar relationships, functionally stable and smooth jaw movements were established. The skeletal, occlusal and functional stability remained satisfactory after a 2-year retention period. In conclusion, miniscrew anchorage was valuable in supporting asymmetric tooth movement during non-extraction appliance treatment in a patient who presented with traumatic unilateral tooth loss.

Backround: The in vitro cytotoxic effects of six different clear aligner materials were evaluated using the MTT analysis.

Methods: The clear aligner material samples [Duran (ScheuDental GmbH, Iserlohn, Germany), Zendura-Flx (Bay Materials LLC, Fremont, CA, USA), Taglus (Laxmi Dental Export Pvt. Ltd, Mumbai, India), Smart Track (Align Technology, San Jose, CA, USA), Zendura (Bay Materials LLC, Fremont, CA, USA), Essix C + (Essix^® (Raintree Essix, Inc., 4001 Division St, Metairie, LA-USA)] were initially kept in a saline solution in airtight test tubes for 8 weeks at 37°C. According to the recommended ISO standards, the weights of the samples were divided by the volumes of the dilutions in the ratio of 0.1 g/ml. To evaluate the cytotoxicity of the samples, an MTT analysis was performed using a human gingival fibroblast cell line (HGF). To analyse the data, the Kruskal– Wallis test was applied (a=0.05).

Results: Zendura was the most cytotoxic material resulting in 67.3 ± 16.20% cell viability, followed by Smart Track with 87.6 ± 5.53% cell viability. While Duran, Essix C + had 92.6 ± 26.34% and 94.9 ± 8.54% cell viability, Zendura-Flx, Taglus had 106.9 ± 12.76% and 113.183 ± 7.45% cell viability, respectively.

Conclusion: While Zendura and Smart Track showed mild cytotoxicity, other materials showed greater cell viabilities. According to the ISO standards, the clinical use of each brand of aligners, except Zendura, may be considered reliable. Taking into account standard deviation, Zendura and Duran should be used with caution. The suppliers of aligners should adhere to the manufacturer’s recommendations since an increase in ion release might arise from material wear.

Objectives: To determine if an association exists between the prevalence of white spot lesions (WSLs) and orthodontic treatment using clear aligners.

Methods: Electronic databases were searched with no restrictions on year. Article selection criteria included human clear aligner studies conducted during the permanent dentition and with a full description of the applied technique and oral hygiene status.

Results: The search strategy resulted in a total of 4177 articles. After title and abstract screening, 156 relevant articles were identified from which five remained after the application of the exclusion criteria. The articles were mostly classified as having a low risk of bias.

Conclusions: Clear aligner therapy induces a lower development rate of new WSLs than orthodontic treatment by fixed appliances. In patients who have poor oral hygiene and/or existing WSLs, clear aligner treatment could be recommended.

Objective: To evaluate the effectiveness and influence of micro-osteoperforation on the rate of canine retraction and patient pain perception.

Method: In this prospective split-mouth clinical trial, forty adult patients in the age range of 15-25 years (18 men and 22 women) requiring bilateral first premolar extraction and upper canine retraction involving maximum anchorage, were enrolled. Two groups of 20 patients each (Group-I and Group-II) were randomly assigned and were further subdivided into subgroups A and B according to the allocation of a maxillary quadrant. Group-I A and Group-II A were the experimental quadrants in which 3 micro-osteoperforations (MOPs) and 2 MOPs were performed, respectively, and Group-I B and Group-II B served as control quadrants. With the help of a mini-screw (1.6 mm diameter, 8 mm length), MOPs were created distal to the maxillary canine following which, canine retraction continued for three months. The collection of data was obtained from monthly plaster models. The primary outcomes were the rate of canine retraction per month and the total distance moved by the canines. The secondary outcomes were to assess patient pain following the MOP procedure.

Result: A significant increase in the rate of tooth movement was seen in Group-I A, whereas, in Group II, there was no significant difference in the movement rate between the subgroups A and B. In addition, Group-I A showed a significant increase in the rate of canine retraction compared to Group-II A. The patients did not report significant pain, nor discomfort nor other complications during or after the procedure.

Conclusion: Micro-osteoperforation appears to be an effective, comfortable, and safe procedure to accelerate tooth movement and significantly reduce the duration of orthodontic treatment.