The effect of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion

Objective: The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion. Methods: Sixty male Sprague-Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated. Results: TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group. Conclusions: Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.ope

The success and effectiveness of miniscrew-assisted rapid palatal expansion are age- and sex-dependent

Objectives: This study aimed to assess the success rate and the amount of suture separation after the miniscrew-assisted rapid palatal expansion (MARPE) procedure in relation to the chronological age and sex of the patients. Materials and methods: The periapical radiographs of 215 subjects (95 male; 120 female; range, 6-60 years) who had undergone MARPE treatment were retrospectively analyzed. The success of suture separation was determined and, in suture-separated subjects, the amount of suture separation was evaluated by suture separation ratio calculated from the periapical radiograph obtained after active expansion. Association tests were performed using linear-by-linear association, the Jonckheere-Terpstra test, Fisher's exact test, and the Mann-Whitney U test, and linear regression models were also developed. Results: The success rate of suture separation was 61.05% in male, 94.17% in female, and 79.53% in both sexes. There was a statistically significant association between older age and suture nonseparation in male (p < 0.001), but not in female (p = 0.221). In suture-separated subjects, there was a statistically significant trend toward a low amount of suture separation with older age subgroups in both sexes (p < 0.001); however, there was no statistically significant difference in the amount of suture separation between male and female in all age subgroups. Conclusions: Older patients treated with MARPE, particularly in male, may have a reduced likelihood of both success in suture separation and sufficient basal bone expansion. Clinical relevance: This study demonstrates that clinicians should consider that the success rate of MARPE and the amount of suture separation may depend on chronological age and sex.ope

Total intrusion and distalization of the maxillary arch to improve smile esthetics

This case report illustrates the successful treatment of a patient with skeletal Class II malocclusion and an unesthetic smile involving excessive gingival display and large buccal corridors. By applying dual buccal interradicular miniscrews, total intrusion of the maxillary dentition along with distalization was induced to improve both the occlusion and smile esthetics. In addition to the conventional cephalometric superimposition, three-dimensional superimposition was performed and evaluated to validate the treatment outcome.ope

Esthetic Improvement of the Maxillary Anterior Teeth during the Ten Years after Single-Implant Restoration Replacing an Ankylosed Maxillary Central Incisor in a Class II Malocclusion

This case report illustrates the long-term changes of an adult Class II malocclusion treated with premolar extraction and a single-implant restoration replacing an ankylosed upper central incisor. A 20-year-old female showing Class II malocclusion with maxillary protrusion and ankylosed upper central incisor due to previous trauma visited the clinic. To improve the occlusion, first premolars of the maxillary and mandibular arch were extracted followed by comprehensive orthodontic treatment. After orthodontic treatment, the ankylosed upper incisor was extracted and replaced with a dental implant. Overall, the occlusion was stably maintained during the 10 years of retention. Interestingly, the interdental papilla between the implant and the adjacent central incisor and the gingival soft tissue continued to remodel over time improving the micro-esthetics of the maxillary incisor region as well as the occlusion.ope

Long-term survival of retained deciduous mandibular second molars and maxillary canine incorporated into final occlusion

Orthodontic treatment of a complex case that involves retained deciduous mandibular second molars with missing permanent successors is challenging. Usually, congenitally missing teeth are manifested with other dental anomalies that further complicate orthodontic treatment, such as retained deciduous teeth, impactions, transpositions and peg-shaped lateral incisors. Even though the long term prognosis of the retained deciduous tooth is not fully predictable, if the teeth are in good condition, the patient and clinician may incline towards a decision to preserve the deciduous teeth as long as possible. This case report demonstrates that deciduous teeth, in this case the mandibular second molars and maxillary canine, can be incorporated into final occlusion with clinically stable long-term results.ope

The comparison of torque values in two types of miniscrews placed in rabbits: tapered and cylindrical shapes: Preliminary study.

OBJECTIVE: This study compared the stability of cylindrical miniscrews (Cy, 7 mm in length) with that of tapered miniscrews (Ta, 5 mm in length), using torque values to determine if the healing time before loading affects the stability of the miniscrew and if the insertion torque is associated with the removal torque measured after a few weeks of healing. METHODS: Ta and Cy with different thread lengths were placed in the tibias of 12 female New Zealand white rabbits (body weight: 3.0 - 3.5 kg), and the maximum insertion torque values (ITV) were measured. No orthodontic forces were applied so as to allow us to determine the pure effects of the different shapes. After 3 different healing periods (2, 4, and 6 weeks), maximum removal torque values (RTV) were measured immediately before the rabbits were sacrificed. RESULTS: No miniscrews were loosened. There were no significant differences in ITV or RTV between the Ta and Cy nor were there any significant differences in the ITV and RTV between the 3 groups, which had different healing periods. There was a correlation between the ITV and RTV. CONCLUSIONS: Shorter Ta showed similar stability as Cy, as determined by torque values. This result strongly suggests that the tapered shape is more advantageous than the cylindrical shape. The RTV did not increase significantly over time. It is recommended that a miniscrew be loaded immediately; waiting a few weeks before loading should be avoided. The correlation between the ITV and RTV suggests that the ITV can be used to estimate a screw's future stability.ope

Variations in position of the maxillary lateral incisor in cleft alveolus

Alveolar bone graft allows a tooth adjacent to cleft alveolus to erupt. When the cleft is located distal to the lateral incisor, bone graft is performed for the canine; while it is necessary for the lateral incisor if the cleft is located mesial to the lateral incisor. This study was performed to investigate position of the maxillary lateral incisor to the cleft and to decide appropriate timing for alveolar bone graft. Position of the maxillary lateral incisor was evaluated for 139 patients who had been diagnosed as cleft alveolus. Congenital missing of the maxillary lateral incisor was noted 40% (n = 55); distal position to the cleft, 46% (n = 64); mesial, 9% (n = 13); mesial and distal, 5% (n = 7). The maxillary lateral incisor was most commonly found distal to the cleft, which indicates the alveolar bone graft needs to be performed for eruption of the lateral incisor.ope

Skeletal myogenic differentiation of human periodontal ligament stromal cells isolated from orthodontically extracted premolars

OBJECTIVE: To investigate the stem cell-like characteristics of human periodontal ligament (PDL) stromal cells outgrown from orthodontically extracted premolars and to evaluate the potential for myogenic differentiation. METHODS: PDL stromal cells were obtained from extracted premolars by using the outgrowth method. Cell morphological features, self-replication capability, and the presence of cell-surface markers, along with osteogenic, adipogenic, and chondrogenic differentiation, were confirmed. In addition, myogenic differentiation was induced by the use of 5-aza-2'-deoxycytidine (5-Aza) for DNA demethylation. RESULTS: PDL stromal cells showed growth patterns and morphological features similar to those of fibroblasts. In contrast, the proliferation rates of premolar PDL stromal cells were similar to those of bone marrow and adipogenic stem cells. PDL stromal cells expressed surface markers of human mesenchymal stem cells (i.e., CD90 and CD105), but not those of hematopoietic stem cells (i.e., CD31 and CD34). PDL stromal cells were differentiated into osteogenic, adipogenic, and chondrogenic lineages. Myotube structures were induced in PDL stromal cells after 5-Aza pretreatment, but not in the absence of 5-Aza pretreatment. CONCLUSIONS: PDL stromal cells isolated from extracted premolars can potentially be a good source of postnatal stem cells for oromaxillofacial regeneration in bone and muscle.ope

Autotransplantation of a Third Molar as a Lower Second Molar Combined with Orthognathic Surgery

We report the treatment of an adult Class II malocclusion with severe crowding and a hopeless lower second molar. According to the treatment plan, 4 premolars and 4 third molars were to be extracted for 2-jaw surgery. To replace the hopeless lower second molar, one upper third molar was successfully autotransplanted during the pre-surgical orthodontic treatment. Multiple teeth are frequently extracted for treatment purposes in adult surgical cases. Under precise diagnosis, the reuse of extracted teeth to replace missing teeth can be a successful alternative even in adult surgical patients.ope

Thermo-mechanical properties of 3D printed photocurable shape memory resin for clear aligners

To overcome the limitations of the conventional vacuum thermoforming manufacturing method, direct 3D printing of clear aligners has been developed. The present study investigated the thermo-mechanical and viscoelastic properties of a photocurable resin TC-85, which is a new material for the direct 3D printed clear aligners, comparing to a conventional thermoplastic material polyethylene terephthalate glycol. Dynamic mechanical analysis was performed to analyse the mechanical behaviours of the two materials at 37 °C and 80 °C, respectively. Furthermore, the shape memory property of the two materials was evaluated using a U-shape bending test, and the shape recovery ratio for 60 min at 37 °C was calculated. The results indicate that TC-85 can constantly apply a light force to the teeth when used for the 3D printed clear aligners, owing to its flexibility and viscoelastic properties. In addition, it is expected that the force decay induced by repeated insertion of the clear aligners will be reduced and a constant orthodontic force will be maintained. Furthermore, its geometric stability at high temperatures and the shape memory properties provide advantages for the clinical application.ope