Objective: Since its establishment in 1981, the Orthodontics department of the Chiba Dental Medical Center of Tokyo Dental College has been committed to providing orthodontic treatment to patients with cleft lip and/or palate who have occlusal abnormalities, in collaboration with other medical hospitals that cleft lip and palate patients with different techniques of lip and palatoplasty for malocclusion. This study investigated the prevalence of crossbite among cleft lip and palate patients, conducting a comprehensive clinical and statistical analysis of its dynamics. In addition, we investigated the evolution of crossbite in institutions that perform palatoplasty with different techniques while also assessing the role of our department within the local community.
 Methods: Over the span of 40 years, from the establishment of Tokyo Dental College Chiba Hospital in 1981 to 2020, 1,254 patients with cleft lip and palate were admitted for treatment. This study examined 470 cases who underwent palatoplasty, i.e., isolated cleft palate, and unilateral or bilateral cleft lip and palate. All cases were at the stage of initiation of active orthodontic treatment. Using parallel study models, the incidence of crossbite was classified based on its position and the dimensions of the dental arch were calculated. Additionally, a comparative study was conducted between the two primary referral hospitals with different palatoplasty techniques to examine variations in crossbite occurrence associated with different palatoplasty techniques.
 Results: When classifying patients based on the position of their crossbite, the percentage of Type 1 patients without crossbite increased, while the percentage of Type 6 patients with overall crossbite decreased from Phase 1 to 4. There were no significant changes in the length and width of the dental arch over time. Therefore, it was hypothesized that changes in the anteroposterior relationship between the maxillomandibular arch, rather than changes in the shape of the dental arches, play a role in decreasing crossbite. Regarding the position of crossbite incidence in relation to the palatoplasty method, a significant difference was noted only in Phase 2 of bilateral cleft lip and palate, where Type 6 had a notably high ratio, suggesting that two-stage palatoplasty had a better treatment outcome. However, no significant variations were observed in other cleft types suggesting no significant differences were observed in the classification of crossbites based on various palatoplasty techniques.
 Conclusions: The incidence of crossbite in patients with cleft palate, as well as unilateral and bilateral cleft lip and palate, at the department has shown a decreasing trend over time. There was no relationship between the position of the crossbite and changes in the width or length of the dental arch. Furthermore, differences in palatoplasty did not affect the classification of crossbite.

 Recently, more centers are performing gingivoperiosteoplasty（GPP）to achieve early cleft closure for infants with cleft lip and palate. In many cases, presurgical infant orthopedics（PIO）must be performed prior to GPP for the molding of alveoli. However, some studies suggest that PIO and GPP cause narrowing of the maxillary arch and suppress maxillary growth. Therefore, the three-dimensional morphology of the maxilla was evaluated by analyzing computed tomography（CT）images obtained immediately after PIO and GPP in infants with complete unilateral cleft lip and alveolus（UCLA）. To compare the values of UCLA, CT images were also taken from age-matched infants with incomplete UCLA and infants without clefts.
 CT images of infants with complete and incomplete UCLA who underwent primary surgery at Kanagawa Children’s Medical Center were taken under sedation at 2 weeks postoperatively. All infants with complete UCLA（n = 24）underwent simultaneous GPP and cheiloplasty as the primary surgery after PIO（Group A）. The infants with incomplete UCLA（n = 11）did not undergo PIO; only cheiloplasty was performed as the primary surgery（Group B）. The anteroposterior length, vertical position, and transverse width of the maxilla and the lateral deviation of the anterior nasal spine were three-dimensionally measured in the CT images. CT images were taken from 25 age-matched infants with otitis media and used for references.
 There were no significant differences in the anteroposterior length, vertical position, or transverse width of the maxilla between groups A and B. The lateral deviation of the anterior nasal spine was significantly larger in Group A than in Group B.
 These findings suggest that PIO was not likely to cause narrowing or shortening of the maxilla in infants with complete UCLA immediately after surgery.

 Children with cleft palate are known to have a high incidence of otitis media effusion and are refractory to treatment with tympanic tube placement. The importance of early diagnosis and treatment of hearing loss has been strongly recognized with the spread of newborn hearing screening. Against this backdrop, the number of cases of tube placement within the first year of life in children with cleft palate and exudative otitis media has been increasing. In this study, we investigated the differences in the frequency of ear leakage, postoperative condition at home, and family psychology depending on the timing of tube placement. The subjects were 83 patients who had tubes implanted between January 2018 and October 2022, and for whom more than six months had passed since implantation. The patients were divided into three groups according to the time of tube placement: 30 were under 1 year of age, 40 were in the 1-year age range, and 13 were 2 years of age or older, with the mean age of placement in each group being 5.17 months, 14.3 months, and 56.5 months, respectively. The results showed that 27（90％）, 26（65％）, and 7（53.8％）of the families in each group felt that their children’s response to sound had improved. In addition, 8（26.7％）, 3（7.5％）, and 0（0％）of the families felt that their children’s emotional conditions had improved. It was found that many of the families in the under 1 year old group felt improvement in both the daily life and emotional aspects. Next, with regard to ear leakage, 4（13.3％）, 20（50％）, and 5（38.5％）of the patients in each group had no ear leakage, and 12（40％）, 10（25％）, and 3（23.1％）of the patients in the under 1 year old group had ear leakage that did not stop for a week or more, indicating a high likelihood of ear leakage and a low likelihood of stopping. However, while ear leaks were more common, they were less likely to be stopped at the hospital. However, while ear leakage was common, 3（10.0％）, 12（30％）, and 2（15.4％）of the families in each group felt it was a burden to go to the hospital. In terms of family psychology, 27（90％）, 28（70％）, and 8（61.5％）of the families in each group felt that they were glad their children had undergone surgery. Although ear leaks are more frequent when tubes are placed during infancy, many families were glad the surgery was performed because of the improvement in the child’s life and emotional state, and the sense of security that the otitis media could be treated. The results of the study showed that the families were happy that their children had undergone the surgery.

 Purpose: In two-stage palatal repair, the soft palate and the posterior half of the hard palate are closed at 1 year 6 months in the first operation. In the second, closure of the residual anterior half of the hard palate and alveolar bone grafting are performed simultaneously at 6-7 years of age. We evaluated the impact of this procedure on speech function.
 Methods: The subjects were 36 consecutively treated patients with complete unilateral cleft lip and palate. Patients underwent the first and second operation at a mean age of 1 year 8 months and 6 years 8 months, respectively. After the first operation, 18 patients did not wear a palatal plate as an obturator (non-plate group) as the unclosed cleft reduced remarkably in the anterior half of the hard palate. A total of 18 patients wore a palatal plate (plate group) as the unclosed cleft was opened widely and there was nasal emission, affecting adequate articulation. Velopharyngeal closure function (VPC) and articulation were evaluated at a mean age of 5 years 1 month and 7 years 5 months before (age 5) and after the second operation (post-2nd), respectively, and we considered the non-plate and plate groups.
 Results: In all cases, the acquisition rate of excellent and good VPC was 88.9％ at age 5 and 94.4％ at post-2nd. The acquisition rate of acceptable and intelligible speech (adequate articulation) increased from 44.4％ at age 5 to 61.1％ at post-2nd. The acquisition rate of excellent and good VPC in the plate group was significantly lower at 77.8％ compared to 100％ in the non-plate group at age 5. VPC was good with no significant difference at 94.4％ in both groups at post-2nd. No significant difference was observed in the acquisition rate of adequate articulation in the non-plate (55.6％) and plate group (33.3％) at age 5. The acquisition rate increased to 83.3％ in the non-plate group but remained significantly low at 38.9％ and showed no improvement in the plate group at post-2nd.
 Conclusions: Half of all cases that were able to avoid the use of a palatal plate obtained good VPC at age 5 and adequate speech outcome in almost all cases at post-2nd. Articulation disorder in the other half that needed to use the palatal plate did not improve even at post-2nd. To facilitate speech development without delay, an unclosed cleft should be reduced to the appropriate size without adversely affecting VPC acquisition before 5 years of age at the latest.