Two-thirds anteroposterior ramus length is the preferred osteotomy point for intraoral vertical ramus osteotomy.

OBJECTIVES: This study aimed to investigate the mandibular canal of ramus and design a suitable osteotomy line for intraoral vertical ramus osteotomy (IVRO) using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Ninety patients were classified into class I, II, and III skeletal pattern groups. When extended from the horizontal base plane (0 mm, mandibular foramen [MF]), with a 2-mm section interval, to 10 mm above and 10 mm below the MF, the following landmarks were identified: external oblique ridge (EOR), posterior border of the ramus (PBR), and posterior lateral cortex of ramus (PLC): IVRO osteotomy point. RESULTS: In the base plane (0-mm plane), the EOR-PBR distance of class III (34.78 mm) and the IOR-PBR distance of class II (32.72 mm) were significantly higher than those of class I (32.95 mm and 30.03 mm). Compared to the EOR-PLC distance, the designed osteotomy point (two-thirds EOR-PBR length) has a 3.49-mm safe zone at the base plane and ranging from 0.89 mm (+ 10-mm plane) to 8.37 mm (- 10-mm plane). CONCLUSIONS: The position at two-thirds EOR-PBR length (anteroposterior diameter of the ramus) can serve as a reference distance for the IVRO osteotomy position. CLINICAL RELEVANCE: Mandibular setback operations for treating mandibular prognathism mainly include sagittal split ramus osteotomy (SSRO) and IVRO. IVRO has a markedly lower incidence of postoperative lower lip paraesthesia than SSRO. Our design presented a reference point for identification during IVRO, to prevent damage to the inferior alveolar neurovascular bundle.

Clinical significance of postoperative skeletal relapse in the treatment of mandibular prognathism: Receiver operating characteristic curve analysis.

BACKGROUND/PURPOSE: Postoperative skeletal relapse is the most important issue in patients undergoing orthognathic surgery. This study aimed to investigate clinical skeletal relapse (≥2 mm) after mandibular setback surgery (intraoral vertical ramus osteotomy: IVRO) using receiver operating characteristic curve (ROC curve) analysis. METHODS: Serial cephalograms of 40 patients with mandibular prognathism were obtained at different time points: (1) before surgery (T1), (2) immediately after surgery (T2), and (3) at least with a 2-year follow-up postoperatively (T3). The menton (Me) was used as the landmark for measuring the amount of mandibular setback and postoperative skeletal relapse. Postoperative stability (T32) was divided into groups A and B by skeletal relapse ≥2 mm and <2 mm, respectively. The area under the ROC curve (AUC) was used to determine the cut-off point for mandibular setback. RESULTS: At the immediate surgical setback (T21), the amount of setback in group A (15.55 mm) was significantly larger than in group B (10.97 mm). Group A (T32) showed a significant relapse (4.07 mm), while group B showed a significant posterior drift (1.23 mm). The amount of setback had the highest AUC area (0.788). The cut-off point was 14.1 mm (T21) that would lead to a clinical relapse of 2 mm (T32). CONCLUSION: In IVRO, the postoperative mandibular positions reveal posterior drift and anterior displacement (relapse). The experience of clinical observation and patient perception of postoperative skeletal relapse was ≥2 mm. In the ROC curve analysis, the cut-off point of setback was 14.1 mm.

Comparison of Intraoperative Blood Loss and Postoperative Pain After Two Different Anterior Mandibular Osteotomies.

PURPOSE: The aim of this study was to compare intraoperative blood loss and postoperative pain in patients undergoing 2 different procedures for the treatment of bimaxillary protrusion with chin deficiency: anterior subapical osteotomy (ASO) of the maxilla (ASO Mx), ASO of the mandible (ASO Md), and genioplasty (Gep); and ASO Mx, bilateral parasymphyseal osteotomy (BPsO) of the mandible (BPsO Md), and Gep. MATERIALS AND METHODS: A 10-cm visual analog scale (VAS) was used to evaluate postoperative pain >2 days in 32 patients who underwent orthognathic surgery. According to osteotomy of mandible, patients were divided into 2 groups: 15 in the ASO group and 17 in the BPsO group. Patient- and operation-related factors (age, blood loss, operation time, and pre and postoperative blood parameters) were assessed, and postoperative pain using VASs were compared between both groups. RESULTS: Patient- and operation-related factors showed no significant difference in both groups. Mean operation time and blood loss were 406.67 minutes and 388.67 mL in the ASO group, and 447.35 minutes and 365 mL in the BPsO group. Mean VAS scores on the first and second postoperative days were 3 and 1.4 cm in the ASO group, and 2.82 and 1.76 cm in the BPsO group, also indicating no significant between-group differences. CONCLUSION: Intraoperative blood loss and postoperative pain control following orthognathic surgery were within acceptable parameters, with no significant differences between the ASO and BPsO procedures.

Correlation Between Blood Loss and Patient-Related Factors in the Bilateral Parasymphyseal Osteotomy.

The aim of this study was to determine the correlation between pre- and postsurgical loss of blood and blood components among patients undergoing treatment of facial deformities by bilateral parasymphyseal osteotomy (BPsO).The pre- and postoperative values of blood components were determined in 30 facial deformity patients who underwent orthognathic surgery by hypotensive anesthesia. Correlations among the blood loss, sex, age, operation time, and reduced values of blood components were assessed by a correlation matrix. The mean blood loss and operation time were 437.5 (± 52.5) mL and 355.8 (± 209.42) minutes, respectively. Two patients included in this study had required blood transfusion. The mean reduced red blood cell (× 10/µL), hemoglobin (g/dL), and hematocrit (%) were -1.02, -2.98, and -9.18, respectively. There was no significant correlation between blood loss and other related factors (eg, age, operation time, and reduced blood components). All patients, however, showed significantly lower values of blood components after surgery. In conclusion, no significant factor was associated with blood loss and reduced blood components among patients undergoing BPsO. Furthermore, hypotensive anesthesia is a well-accepted method to reduce blood loss during orthognathic surgery.

Impact of removable dentures on oral health-related quality of life among elderly adults in Taiwan.

BACKGROUND: Although the use of removable dentures can improve oral function and esthetics for elderly people, compared to those who do not wear removable dentures, those wearing removable dentures could have worse oral health related-quality of life (OHRQoL). Additional information is required to assess which factors related to denture wearing influence the OHRQoL of elderly individuals. The purpose of this study is to evaluate the association between denture wearing and OHRQoL in a sample of elderly individuals in Taiwan. METHODS: The study population included 277 elderly people wearing removable dentures (mean age = 76.0 years). Using face-to-face interviews, we collected data on the participants' socio-demographic characteristics, dental care service usage (regular dental checkups, treatment during toothache, dental visits in the last year), and factors related to denture wearing (perceived oral pain, perceived loose denture, perceived oral ulcer, perceived halitosis, perceived dry mouth, and perceived total denture satisfaction scores). OHRQoL was measured using the Taiwanese version of the Geriatric Oral Health Assessment Index (GOHAI-T). The location and number of remaining natural teeth and the type of denture were also recorded. Hierarchical multiple regression analysis was performed using GOHAI-T scores as the dependent variable. RESULTS: All the predictors together accounted for 50% of the variance in GOHAI-T scores. Further, education level, number of natural teeth, denture status, perceived loose denture, perceived oral ulcer, and perceived total denture satisfaction scores had statistically significant influences on OHRQoL. When compared with other variables, factors related to denture wearing, especially perceived total denture satisfaction scores, had the greatest impact on GOHAI-T scores. CONCLUSIONS: Of the factors analyzed in this study, denture satisfaction was the strongest predictor of OHRQoL. This suggests that denture satisfaction is useful for assessing the effect of denture treatment on the OHRQoL of elderly individuals wearing removable dentures.

Masticatory factors as predictors of oral health-related quality of life among elderly people in Kaohsiung City, Taiwan.

OBJECTIVE: This study aimed to evaluate which masticatory factor is the best predictor of oral health-related quality of life (OHRQoL) in elderly Taiwanese individuals aged 65 years and older. METHODS: Subjects were 332 community-dwelling, independently living elderly adults (mean age, 76.0 ± 0.4 years) in Kaohsiung City, Taiwan. Information concerning age, gender, and socioeconomic status was collected via face-to-face interview questionnaires; the number of food groups rated 'easy to chew' was determined by using food intake questionnaires; and OHRQoL data were obtained by using the Taiwanese version of the Geriatric Oral Health Assessment Index (GOHAI-T). The number of natural teeth, functional tooth units, and posterior occlusal contacts according to Eichner Index was assessed by dental examination. Multiple regression analysis was conducted to determine the best masticatory factor that could serve as a predictor of GOHAI scores. RESULTS: The number of food groups rated 'easy to chew' was found to be the only masticatory factor affecting GOHAI-T scores, after adjustment for age, gender, socioeconomic status, and other masticatory variables. As compared to subjects who listed less food groups as 'easy to chew,' subjects who rated more food groups as 'easy to chew' were less likely to have low GOHAI-T scores. CONCLUSIONS: Of the masticatory predictors analyzed in this study, perceived masticatory ability, as measured using a food intake questionnaire, could be the best masticatory predictor of OHRQoL in the elderly.

Maturation of the Female Pharyngeal Airway from Adolescence to Adulthood.

BACKGROUND: The present study aimed to investigate developmental changes in the female pharyngeal airway from adolescence to adulthood, considering variations in the anatomical structures related to the airway dimensions. METHODS: Lateral cephalograms of 214 females were analyzed and categorized into five developmental stages: early adolescence (10-13 years), middle adolescence (14-17 years), late adolescence (18-21 years), early adulthood (22-30 years), and middle adulthood (31-50 years). The focus of the analysis included the point A-Nasion-point B (ANB) angle, tongue pharyngeal airway space (TPS), epiglottis pharyngeal airway space (EPS), soft palate airway space (SPS), and the horizontal and vertical positions of the hyoid bone. RESULTS: The ANB angle exhibited significant variation across groups, being significantly larger in the early-adolescence group (4.22°) compared to the middle-adolescence, late-adolescence, and early-adulthood groups. The TPS and EPS were significantly shorter in the early-adolescence group. Negative correlations were observed between the ANB angle and the lengths of the pharyngeal airway spaces (SPS, TPS, and EPS). The horizontal and vertical positions of the hyoid bone remained stable after middle adolescence. CONCLUSION: The maturation of the ANB angle and pharyngeal airway in females seems nearly completed during middle adolescence (14-17 years). Additionally, a significant and negative correlation was identified between the ANB angle and the lengths of various pharyngeal airway spaces (SPS, TPS, and EPS). The horizontal and vertical positions of the hyoid bone showed stability after middle adolescence.

Impact of oral health behaviours and oral habits on the number of remaining teeth in older Taiwanese dentate adults.

PURPOSE: To evaluate the impact of oral health behaviours and oral habits on the number of remaining teeth in older Taiwanese dentate adults. SUBJECTS AND METHODS: Subjects comprised dentate patients (mean age, 60.0 ± 9.9 years) in Taiwan. Information on demographic data, oral health behaviours, oral habits and self-perceived health status was collected via self-administered questionnaires and dentition status was assessed by oral examination. Multiple logistic regression analyses were used to determine variables correlated with the low dentition group (subjects with less than 20 natural teeth or 8 functional tooth units). RESULTS: The analysis showed that the low dentition group was more likely to be older and to exhibit low educational levels, less frequent use of dental floss, more common smoking habits, poor self-perceived dental health and to be exbetel- nut chewers. In addition, the low dentition group was less likely to be current betel-nut chewers. CONCLUSIONS: These results underscore the importance of the use of dental floss and confirm the adverse effects of smoking on dental health. Hence, the dental profession should continue to encourage proper oral health behaviours and oral habits.

Locating the Mandibular Lingula Using Cone-Beam Computed Tomography: A Literature Review.

This study aimed to review the literature on adult mandibular lingula (ML) locations and related distances determined using cone-beam computed tomography (CBCT). A search was conducted for studies on CBCT using the following databases: PubMed, Web of Science, and Embase. The search results were limited to studies published between 1970 and 2021. The inclusion criteria were the investigation of ML location, CBCT, and participants aged ≥18 years. Eligible studies were examined for the distances from the lingual tip to the anterior ramus border, posterior ramus border, sigmoid notch, inferior ramus border, and occlusal plane. Eight studies on CBCT qualified for inclusion in the study. The mean distances from the ML to the anterior ramus border were 15.57 to 20 mm. In most of these, the ML was located above the occlusal plane. No significant differences were observed in the location and related distances for the ML among patients of different sexes, ethnicities, or skeletal patterns.

Morphological Study of the Mandibular Lingula and Antilingula by Cone-Beam Computed Tomography.

The patterns of the lingula and antilingula are crucial surgical reference points for ramus osteotomy. Cone-beam computed tomography (CBCT) provides three-dimensional images, and patient radiation dose is significantly lower for CBCT than for medical CT. The morphology of the mandibular lingula and antilingula of ninety patients (180 sides) were investigated using CBCT. The lingula were classified as having triangular, truncated, nodular, and assimilated shapes. The antilingula were classified as having hill, ridge, plateau, and plain shapes. The patients' sex, skeletal patterns (Classes I, II, and III), and right and left sides were recorded. The most to least common lingula shapes were nodular (37.8%), followed by truncated (32.8%), triangular (24.4%), and assimilated (5%). The most to least common antilingulae were hill (62.8%), plain (18.9%), plateau (13.9%), and ridge (4.4%) patterns, respectively. The lingula and antilingula had identical patterns on both sides in 47 (52.2%) and 46 patients (51.1%), respectively. Sex and skeletal pattern were not significantly correlated to lingula and antilingula shapes. No significant correlation was observed between lingula and antilingula shapes.

Evaluation of a self-assessed screening test for masticatory ability of Taiwanese older adults.

OBJECTIVES: The aim of this study was to evaluate a screening test based on a food intake questionnaire to discriminate the masticatory ability of Taiwanese older adults with 20 and more natural teeth and at least 8 functional tooth units (FTUs) from the masticatory ability of those with fewer than 20 natural teeth and 8 FTUs. MATERIALS AND METHODS: The subjects were 2244 patients (mean age, 60.4±10.0 years) recruited from 23 counties and cities in Taiwan. Information about their demographic data, dentition, and masticatory ability was collected. Masticatory ability was measured for 23 food groups comprising 35 common Taiwanese foods, and receiver operation characteristic curve analysis was performed. RESULTS: The results showed that the final questionnaire included 14 food groups and a subject choosing 'difficult to eat' responses for 4 and more of these food groups had the same masticatory ability as individuals with fewer than 20 natural teeth and 8 FTUs. CONCLUSION: In conclusion, foods that are the most difficult to eat are not necessarily good discriminatory indicators. Hence, the 14-food group questionnaire can be considered the best screening test for masticatory ability of Taiwanese older adults in terms of the presence of 20 and more natural teeth and at least 8 FTUs.

Detrimental effects of maternal lead exposure during pregnancy and lactation on molar development in the young rat.

The purpose of this animal study was to investigate the influence of maternal lead exposure during pregnancy and lactation on molar development in the offspring. Scanning electron microscopy revealed no significant differences in the molar morphology among the groups. However, in all the experimental groups, deep, wide cracks were found in the occlusal enamel. Further, the experimental groups had smaller molar diameters than the control group, lead exposure during lactation had a greater influence on the molar size in the offspring, and the groups with the higher dose of lead exposure during pregnancy and lactation had significantly smaller molar sizes than the groups that received the lower dose. The mesiodistal and buccolingual diameters of molars were measured as 3.10 ± 0.07 and 1.95 ± 0.04 mm for control group, 2.97 ± 0.08 and 1.94 ± 0.01 mm for lactation group of low dose, 2.96 ± 0.05 and 1.84 ± 0.02 mm for lactation group of high dose, 3.09 ± 0.06 and 1.94 ± 0.04 mm for pregnancy group of low dose, and 3.02 ± 0.06 and 1.85 ± 0.06 mm for pregnancy group of high dose, respectively.

Morphological Investigation of Mandibular Lingula: A Literature Review.

PURPOSE: The purpose of the study was to review the literature on the shape of the mandibular lingula. METHODS: English articles published from 1970 to 2021 in databases (PubMed, Web of Science, and Embase) were selected. Articles meeting the search strategy were evaluated based on the eligibility criteria (participants aged 18 years and over). Dry mandibles and cone beam computed tomography (CBCT) images were used as research materials. The shapes of mandibular lingula were classified as triangular, truncated, nodular, and assimilated. RESULTS: Based on the eligibility criteria, 10 articles (six with dry mandibles and four with CBCT images) were selected for full-text reading and detailed examination. In the dry mandible group, triangular, truncated, nodular, and assimilated lingula were observed on 446, 398, 232, and 69 sides, respectively. In the CBCT group, nodular, truncated, triangular, and assimilated lingula were observed on 892, 517, 267, and 88 sides, respectively. Therefore, the most common lingula types in the dry mandible and CBCT groups were different. The assimilated type was the least common in both groups. CONCLUSION: In the dry mandible group, the most common lingula type was triangular, followed by truncated, nodular, and assimilated types. In the CBCT group, the most common lingula type was nodular, followed by truncated, triangular, and assimilated types. There were no significant differences in lingula types between the left and right sides of the mandible.

Changes in Facial Profile after Modified Anterior Maxillary Subapical Osteotomy.

(1) Background: This study explored the effects of modified anterior maxillary subapical osteotomy (AMSO) on facial profile changes in patients with bimaxillary protrusion. (2) Methods: Cephalograms of patients were collected preoperatively and over 2 months postoperatively. The following landmarks were recorded: pronasale (Prn), subnasale (Sn), labrale superius (Ls), anterior nasal spine (ANS), and incisor superius (Is). The following distances and angles were measured: ANS-Prn, ANS-Sn, ANS-Ls, Is-Sn, Is-Ls, SNA angle, and nasolabial (NLA) angle. (3) Results: Is and ANS were significantly retracted by 7.3 and 2.3 mm, respectively. Soft tissue landmarks (Prn, Sn, and Ls) were significantly retracted (1.2, 1.6, 4.4 mm, respectively). Postoperative changes in soft/hard tissue ratios were 0.54, 0.72, 0.31, and 0.60 for Prn/ANS, Sn/ANS, ANS/Is, and Ls/Is, respectively. The NLA angle was increased significantly by 7.1°. (4) Conclusions: The horizontal soft/hard tissue ratios of Sn/Is, ANS/Is, and Ls/Is were 0.22, 0.31, and 0.60, respectively. The NLA angle was increased significantly by 7.1°. The modified AMSO provides an increased blood supply, allows for direct vision, and results in fewer complications than other AMSO methods.

Assessment of the related factors of blood loss and blood ingredients among patients under hypotensive anesthesia in orthognathic surgery.

OBJECTIVE: The objective of the study was to understand the factors associated with presurgical and postsurgical blood loss and blood ingredients among patients in the treatment of mandibular prognathism by intraoral vertical ramus osteotomy combined genioplasty. METHODS: Preoperative and postoperative values of blood loss and blood ingredients were collected from 30 mandibular prognathic patients who underwent orthognathic surgery. The linear regression models and correlation coefficients were used to identify factors with respect to patients' blood loss level and 3 types of blood ingredients (ie, red blood cells, hemoglobin, and hematocrit). RESULTS: The mean blood loss and operation time were 179.2 mL and 311.7 minutes, respectively. No blood transfusion was received by our patients. After adjusting for potential factors, the regression models showed that no significant factor was found to be associated with blood loss and reduce blood ingredients. Moreover, female patients were found to be more likely to have a low level of presurgical blood ingredients (ß = -0.293 to -3.551; P < 0.05), whereas female sex (ß = -1.606 to -4.008; P < 0.001), a high blood loss level (ß = -0.003 to -0.009; P < 0.05), and long operation time (ß = -0.005 to -0.018; P < 0.05) were associated with a low level of postsurgical blood ingredients (ie, hemoglobin and hematocrit). CONCLUSIONS: No significant factor was associated with blood loss and reduced blood ingredients among patients in orthognathic surgery with hypotenstive anesthesia. Improvements in anesthesia provided surgeons with more time to promote hemostasis during surgery. Hypotensive anesthesia was a well-accepted method to reduce blood loss during orthognathic surgery.

Investigation of Immediate Postoperative Pain following Orthognathic Surgery.

PURPOSE: The purpose of this study was to compare postintervention pain related to orthodontic treatment and orthognathic surgery. Material and Methods. One hundred patients who received only orthodontic treatment are the nonsurgical group. One hundred other patients were separated equally into the following four orthognathic surgical subgroups. The visual analog scale (VAS) score was used to measure postoperative pain. Patient- and operation-related factors were compared among the four surgical subgroups. The null hypothesis was that there was no difference between orthodontic treatment and orthognathic surgery in terms of posttreatment pain. RESULTS: There were no significant differences between the nonsurgical and surgical groups for gender (P = 0.780) or age (P = 0.473). The VAS scores of the nonsurgical group (mean: 3.59) were significantly (P = 0.007) higher than those of the surgical group (mean: 3.06). The null hypothesis was rejected. Within the surgical subgroups, no significant differences were observed between the men and women for age, operation time, blood loss volume, or blood laboratory values. CONCLUSIONS: The VAS scores of the orthodontic (nonsurgical) group were significantly higher than those of the surgical group. No significant differences in VAS scores were found between the four surgical subgroups.

Investigation of the Effectiveness of Surgical Treatment on Maxillary Medication-Related Osteonecrosis of the Jaw: A Literature Review.

AIM: Medication-related osteonecrosis of the jaw (MRONJ) occurs after exposure to medication (antiresorptive or antiangiogenic agents) for bone-related complications. It is more common in the mandible than in the maxilla. The present study investigated maxillary MRONJ in elderly patients through a meta-analysis. METHODS: Keywords, including "MRONJ", "maxilla", and "surgery", were entered into databases, including Embase, PubMed/MEDLINE, Cochrane Library, and ProQuest, which were searched systematically. RESULTS: Investigating 77 studies, we found that 18 (2 case reports and 16 case series) papers conformed to the standards. The results revealed a 2.6:1 female-to-male ratio of disease occurrence. The average age of patients was 70.6 ± 5.5 years, and most patients were in the third stage (43.6%). The average time of medication usage was 50.0 ± 20.1 months. The pooled proportion of clinical efficacy of surgery was 86%. CONCLUSION: To prevent and manage MRONJ, all elderly patients should maintain proper oral hygiene and receive dental examinations regularly. Risk assessment and safety management of MRONJ should be performed by medical teams.

Effect of Microimplant Neck Design with and without Microthread on Pullout Strength and Destruction Volume.

The microthread neck concept has been applied to dental implants. This study investigated the pullout strength and destruction volume of orthodontic microimplants with and without the microthread neck design. Fifteen microimplants (diameter: 1.5 × 10 mm) of three types (Types A and B: without microimplant neck; Type C: with microimplant neck) were tested. The insertion torque (IT), Periotest value (PTV), horizontal pullout strength (HPS), and horizontal destruction volume (HDV) of each type were measured. Kruskal-Wallis H test and Dunn's post-hoc comparison test were performed to compare the measured values of the three types of microimplants. The correlations of the measured values were used to perform the Spearman's correlation coefficient analysis. The ITs of Types B (8.8 Ncm) and C (8.9 Ncm) were significantly higher than those of Type A (5.2 Ncm). Type B yielded the lowest PTV (4.1), and no statistical differences in PTV were observed among the three types. Type A had a significantly lower HPS (158.8 Ncm) than Types B (226.9 Ncm) and C (212.8 Ncm). The three types did not exhibit any significant differences in the HDV. The results of the Spearman's correlation coefficient test revealed that HDV (ρ = 0.710) and IT (ρ = 0.813) were strongly correlated with HPS, whereas for PTV and HPS, it was not. HPS was strongly and significantly correlated with HDV. The orthodontic microimplant with a microimplant neck design did not perform better than that without a microthread in the mechanical strength test.

Skeletal Stability after Mandibular Setback via Sagittal Split Ramus Osteotomy Verse Intraoral Vertical Ramus Osteotomy: A Systematic Review.

PURPOSE: The purpose of present study was to review the literature regarding the postoperative skeletal stability in the treatment of mandibular prognathism after isolated sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO). MATERIALS AND METHODS: The articles were selected from 1980 to 2020 in the English published databases (PubMed, Web of Science and Cochrane Library). The articles meeting the searching strategy were evaluated based on the eligibility criteria, especially at least 30 patients. RESULTS: Based on the eligibility criteria, 9 articles (5 in SSRO and 4 in IVRO) were examined. The amounts of mandibular setback (B point, Pog, and Me) were ranged from 5.53-9.07 mm in SSRO and 6.7-12.4 mm in IVRO, respectively. In 1-year follow-up, SSRO showed the relapse (anterior displacement: 0.2 to 2.26 mm) By contrast, IVRO revealed the posterior drift (posterior displacement: 0.1 to 1.2 mm). In 2-year follow-up, both of SSRO and IVRO presented the relapse with a range from 0.9 to 1.63 mm and 1 to 1.3 mm respectively. CONCLUSION: In 1-year follow-up, SSRO presented the relapse (anterior displacement) and IVRO posterior drift (posterior displacement). In 2-year follow-up, both of SSRO and IVRO showed the similar relapse distances.

The investigation of pharyngeal airway space by cephalogram landmarks in primary school children in Taiwan.

BACKGROUND/PURPOSE: Proper breathing is essential to healthy growth and development of children. The present study aimed to investigate changes in the pharyngeal airway space in primary-school children. MATERIALS AND METHODS: Cephalometric radiographs were obtained from 93 primary-school children, who were divided into three age groups (Group I, aged 7-8 years; Group II, aged 9-10 years; and Group III, aged 11-12 years). Landmarks identified on each cephalogram included the tip of the uvula (U), hyoid bone (H), and epiglottis (E). Linear and angular measurements comprised nasopharyngeal airway (NP); PS (shortest distance from the soft palate to the pharyngeal wall); UP (distance from the tip of the uvula to the pharyngeal wall); TS (shortest distance from the posterior tongue to the pharyngeal wall); EP (distance, parallel to the X-axis, from the epiglottis to the pharyngeal wall). Statistical analysis was performed using one-way analysis of variance and Pearson correlation tests. RESULTS: Group III had the highest values for all the variables. The three groups exhibited significant differences for all pharyngeal airway variables, except for EP. The three groups had significantly different vertical U, H, and E. There were positive correlations between age and NP, PS, UP, and TS; however, no significant correlation was observed between age and EP. Age significantly correlated with the vertical U, E, and H. Correlations between age and the horizontal U, E, and H were nonsignificant. CONCLUSION: Among primary-school children from various grades, age significantly correlated with all pharyngeal airway variables, except with EP.