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, Jin-Young Choi , Julie McCray, Andrew Hayes, Patricia Schneider, Ki Beom Kim Abstract : Objective: The purpose of this study was to evaluate and compare the dimensional accuracy between thermoformed and direct-printed aligners. Methods: Three types of aligners were manufactured from the same reference standard tessellation language (STL) file: thermoformed aligners were manufactured using Zendura FLXTM (n = 12) and Essix ACETM (n = 12), and direct-printed aligners were printed using Tera HarzTM TC-85DAP 3D Printer UV Resin (n = 12). The teeth were not manipulated with any tooth-moving software in this study. The samples were sprayed with an opaque scanning spray, scanned, imported to Geomagic® Control XTM metrology software, and superimposed on the reference STL file by using the best-fit alignment algorithm. Distances between the aligner meshes and the reference STL file were measured at nine anatomical landmarks. Results: Mean absolute discrepancies in the Zendura FLXTM aligners ranged from 0.076 ± 0.057 mm to 0.260 ± 0.089 mm and those in the Essix ACETM aligners ranged from 0.188 ± 0.271 mm to 0.457 ± 0.350 mm, while in the direct-printed aligners, they ranged from 0.079 ± 0.054 mm to 0.224 ± 0.041 mm. Root mean square values, representing the overall trueness, ranged from 0.209 ± 0.094 mm for Essix ACETM, 0.188 ± 0.074 mm for Zendura FLXTM, and 0.140 ± 0.020 mm for the direct-printed aligners. Conclusions: This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.
, Fábio Lourenço Romano, Murilo Fernando Neuppmann Feres, Maria Bernadete Sasso Stuani, Ana Carla Raphaelli Nahás-Scocate , Mírian Aiko Nakane MatsumotoAbstract : In this report, we demonstrate the effectiveness of the InvisalignⓇ system in the treatment of severe gingival recession and bone dehiscence through torque, translation, and intrusion movements in a young woman. Cone-beam computed tomography was used to assess bone parameters and check the teeth during treatment. The root of the mandibular right central incisor, which was buccally positioned and exhibited bone dehiscence of 9.4 mm, was moved toward the center of the alveolar process by using the InvisalignⓇ system and SmartForceⓇ features. The patient was monitored by a periodontist throughout the orthodontic treatment period. Her gingival recession reduced, while the bone dehiscence reduced from 9.40 mm to 3.14 mm. Thus, movement of the root into the alveolus promoted bone neoformation and treated the gingival recession. The findings from this case suggest that orthodontic treatment using the InvisalignⓇ system, along with periodontal monitoring, can aid in the treatment of gingival recession and alveolar defects.
, Lorenzo Rustico , Miriam Longo, Giacomo Oteri, Moschos A. Papadopoulos, Riccardo NuceraAbstract : Objective: The aim of this systematic review was to evaluate the complications and side effects associated with the clinical use of orthodontic miniscrews by systematically reviewing the best available evidence. Methods: A survey of articles published up to March 2020 investigating the complications associated with miniscrew insertion, in both the maxilla and mandible, was performed using 7 electronic databases. Clinical studies, case reports, and case series reporting complications associated with the use of orthodontic miniscrew implants were included. Two authors independently performed study selection, data extraction, and risk-of-bias assessment. Results: The database survey yielded 24 articles. The risk-of-bias assessment revealed low methodological quality for the included studies. The most frequent adverse event reported was root injury with an associated periradicular lesion, vitality loss, pink discoloration of the tooth, and transitory loss of pulp sensitivity. Chronic inflammation of the soft tissue surrounding the miniscrew with mucosal overgrowth was also reported. The other adverse events reported were lesion of the buccal mucosa at the insertion site, soft-tissue necrosis, and perforation of the floor of the nasal cavity and maxillary sinus. Adverse events were also reported after miniscrew removal and included secondary bleeding, miniscrew fracture, scars, and exostosis. Conclusions: These findings highlight the need for clinicians to preliminarily assess generic and specific insertion site complications and side effects.
, Kyung-Suk Cha , Jin-Woo Lee, Sang-Min LeeAbstract : Objective: The aim of this study was to compare the differences in mandibular posterior anatomic limit (MPAL) distances stratified by vertical patterns in patients with skeletal Class III malocclusion by using cone-beam computed tomography (CBCT). Methods: CBCT images of 48 patients with skeletal Class III malocclusion (mean age, 22.8 ± 3.1 years) categorized according to the vertical patterns (hypodivergent, normodivergent, and hyperdivergent; n = 16 per group) were analyzed. While parallel to the posterior occlusal line, the shortest linear distances from the distal root of the mandibular second molar to the inner cortex of the mandibular body were measured at depths of 4, 6, and 8 mm from the cementoenamel junction. MPAL distances were compared between the three groups, and their correlations were analyzed. Results: The mean ages, sex distribution, asymmetry, and crowding in the three groups showed no significant differences. MPAL distance was significantly longer in male (3.8 ± 2.6 mm) than in female (1.8 ± 1.2 mm) at the 8-mm root level. At all root levels, MPAL distances were significantly different in the hypodivergent and hyperdivergent groups (p < 0.001) and between the normodivergent and hyperdivergent groups (p < 0.01). MPAL distances were the shortest in the hyperdivergent group. The mandibular plane angle highly correlated with MPAL distances at all root levels (p < 0.01). Conclusions: MPAL distances were the shortest in patients with hyperdivergent patterns and showed a decreasing tendency as the mandibular plane angle increased. MPAL distances were significantly shorter (~3.16 mm) at the 8-mm root level.
, Sun-Hyung Park, Jae Hyun Park, Kee-Joon Lee Abstract : Maxillary transverse deficiency often manifests as a posterior crossbite or edge-to-edge bite and anterior crowding. However, arbitrary arch expansion in mature patients has been considered to be challenging due to the possible periodontal adverse effects such as alveolar bone dehiscence and gingival recession. To overcome these limitations, nonsurgical maxillary expansion of the basal bone has been demonstrated in young adults. However, the age range for successful orthopedic expansion has remained a topic of debate, possibly due to the underlying individual variations in suture maturity. This case report illustrates nonsurgical, miniscrew-assisted rapid palatal expansion (MARPE) in a 60-year-old patient with maxillary transverse deficiency accompanied by anterior and posterior crossbites, crowding, and gingival recession. The use of MARPE allowed relief of crowding and correction of the crossbite without causing significant periodontal adverse effects.
, Carlos Flores-Mir, Márcio Rodrigues de Almeida, Bruno da Silva Vieira, Karina Maria Salvatore de Freitas, Daniela Calabrese Nunes, Marcos Cezar Ferreira, Weber UrsiAbstract : Objective: To identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns. Methods: CBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars’ distal roots and second molars’ mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test. Results: There was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns. Conclusions: There was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.
, Hyoung-Seon Baik, Sang-Sun Han, Woowon Jang, Yoon Jeong Choi Abstract : Objective: This study aimed to evaluate the following null hypothesis: there are no differences in the morphology of the temporomandibular joint (TMJ) structures in relation to vertical and sagittal cephalometric patterns. Methods: This retrospective study was performed with 131 participants showing no TMJ symptoms. The participants were divided into Class I, II, and III groups on the basis of their sagittal cephalometric relationships and into hyperdivergent, normodivergent, and hypodivergent groups on the basis of their vertical cephalometric relationships. The following measurements were performed using cone-beam computed tomography images and compared among the groups: condylar volume, condylar size (width, length, and height), fossa size (length and height), and condyle-to-fossa joint spaces at the anterior, superior, and posterior condylar poles. Results: The null hypothesis was rejected. The Class III group showed larger values for condylar width, condylar height, and fossa height than the Class II group (p < 0.05). Condylar volume and superior joint space in the hyperdivergent group were significantly smaller than those in the other two vertical groups (p < 0.001), whereas fossa length and height were significantly larger in the hyperdivergent group than in the other groups (p < 0.01). The hypodivergent group showed a greater condylar width than the hyperdivergent group (p < 0.01). The sagittal and vertical cephalometric patterns showed statistically significant interactions for fossa length and height. Conclusions: TMJ morphology differed across diverse skeletal cephalometric patterns. The fossa length and height were affected by the interactions of the vertical and sagittal skeletal patterns.
, Jeong Won Shin , Hai-Van Giap, Ki Beom Kim, Hwa Sung Chae, Young Ho Kim, Hae Won Choi Abstract : Objective: The aim of this retrospective study was to assess the midfacial soft tissue changes following maxillary expansion using micro-implant-supported maxillary skeletal expanders (MSEs) in young adults by cone-beam computerized tomography (CBCT) and to evaluate the correlations between hard and soft tissue changes after MSE usage. Methods: Twenty patients (mean age, 22.4 years; range, 17.6–27.1) with maxillary transverse deficiency treated with MSEs were selected. Mean expansion amount was 6.5 mm. CBCT images taken before and after expansion were superimposed to measure the changes in soft and hard tissue landmarks. Statistical analyses were performed using paired t-test and Pearson’s correlation analysis on the basis of the normality of data. Results: Average lateral movement of the cheek points was 1.35 mm (right) and 1.08 mm (left), and that of the alar curvature points was 1.03 mm (right) and 1.02 mm (left). Average forward displacement of the cheek points was 0.59 mm (right) and 0.44 mm (left), and that of the alar curvature points was 0.61 mm (right) and 0.77 mm (left) (p < 0.05). Anterior nasal spine (ANS), posterior nasal spine (PNS), and alveolar bone width showed significant increments (p < 0.05). Changes in the cheek and alar curvature points on both sides significantly correlated with hard tissue changes (p < 0.05). Conclusions: Maxillary expansion using MSEs resulted in significant lateral and forward movements of the soft tissues of cheek and alar curvature points on both sides in young adults and correlated with the maxillary suture opening at the ANS and PNS.
, Mattia Longo, Niki Arveda, Michele Nacucchi, Fabio De Pascalis, Giorgio Alfredo Spedicato, Giuseppe Siciliani, Luca Lombardo Abstract : Objective: To assess the effects of thermoforming on aligner thickness and gap width in six aligner systems with the same nominal thickness. Methods: Six passive upper aligners of different brands were adapted to a single printed cast. Each sample was evaluated with high-resolution micro-computed tomography. To investigate aligner thickness and gap width, two-dimensional (2D) analysis was conducted assessing the effects of the following variables: tooth type (central incisor, canine, and first molar), 2D reference points, and aligner type. Data were analyzed and compared using analysis of variance and Tukey’s post-hoc tests (p < 0.05). Results: Tooth type, dental region, and aligner type affected both the gap width and aligner thickness. The aligner thickness remained moderately stable across the arch only in the F22. Conclusions: All thermoformed samples displayed smaller aligner thickness and gap width at anterior teeth and both gingival and coronal centers than at posterior teeth and occlusal surfaces.
, Ningning Sun, Chunmiao Jiang, Yanshan Liu, Jian Sun Abstract : Objective: To examine the accuracy of computer-aided intraoperative navigation (Ci-Navi) in bimaxillary orthognathic surgery by comparing preoperative planning and postoperative outcome. Methods: The study comprised 45 patients with congenital dentomaxillofacial deformities who were scheduled to undergo bimaxillary orthognathic surgery. Virtual bimaxillary orthognathic surgery was simulated using Mimics software. Intraoperatively, a Le Fort I osteotomy of the maxilla was performed using osteotomy guide plates. After the Le Fort I osteotomy and bilateral sagittal split ramus osteotomy of the mandible, the mobilized maxilla and the distal mandibular segment were fixed using an occlusal splint, forming the maxillomandibular complex (MMC). Realtime Ci-Navi was used to lead the MMC in the designated direction. Osteoplasty of the inferior border of the mandible was performed using Ci-Navi when facial symmetry and skeletal harmony were of concern. Linear and angular distinctions between preoperative planning and postoperative outcomes were calculated. Results: The mean linear difference was 0.79 mm (maxilla: 0.62 mm, mandible: 0.88 mm) and the overall mean angular difference was 1.20°. The observed difference in the upper incisor point to the Frankfort horizontal plane, midfacial sagittal plane, and coronal plane was < 1 mm in 40 cases. Conclusions: This study demonstrates the role of Ci-Navi in the accurate positioning of bone segments during bimaxillary orthognathic surgery. Ci-Navi was found to be a reliable method for the accurate transfer of the surgical plan during an operation.
1.361
2021 IF
2.043
5-Year IF
