OBJECTIVE: The purpose of this cross-sectional study was to use multiple regression analysis to evaluate the relationship between the mandibular curve of Spee (COS) and the maxillary compensating curve with dentoskeletal morphology in young Chinese adults with normal occlusion.
METHODS: This study comprised 62 young adults (31 males, mean age: 24.1 ± 2.2 years; 31 females, mean age: 23.3 ± 3.3 years) with Angle class I normal occlusion. For every subject, intraoral scan models of the maxillary and mandibular arches and lateral cephalograms were acquired. The depth of the COS and compensating curve were assessed on the intraoral scan models. Multiple dental arch dimensional and cephalometric variables were screened by univariate analysis. Subsequently, a multiple linear regression model (forward stepwise selection) was constructed to determine which variables were significantly correlated with the two curve depths.
RESULTS: In the mandible, the COS depth was deepest at the mesiobuccal cusp of the first molar. Overjet, mandibular arch width and mandibular-occlusal plane angle significantly correlated with the COS depth (P < 0.05), accounting for 33.1% of the variation in the mandibular COS. In the maxilla, the deepest point of the compensating curve was at the distobuccal cusp of the first molar. Mandibular arch perimeter and overbite significantly correlated with the maxillary compensating curve (P < 0.05), explaining 23.3% of the variation.
CONCLUSIONS: Overjet, overbite, mandibular-occlusal plane angle, mandibular arch width and perimeter should be considered when reconstructing occlusal curves in clinical orthodontic treatment and in prosthetic restoration.
UNASSIGNED: ZIELSETZUNG: Ziel dieser Querschnittsstudie war es, mit einer multiplen Regressionsanalyse die Beziehung zwischen der mandibulären Spee-Kurve („curve of Spee“,COS) und der maxillären Kompensationskurve mit der dentoskelettalen Morphologie bei jungen chinesischen Erwachsenen mit normaler Okklusion zu untersuchen.
METHODS: Die Studie umfasste 62 junge Erwachsene (31 Männer, Durchschnittsalter: 24,1 ± 2,2 Jahre; 31 Frauen, Durchschnittsalter: 23,3 ± 3,3 Jahre) mit normaler Angle-Klasse-I-Okklusion. Für jeden Probanden wurden intraorale Scanmodelle der Ober- und Unterkieferzahnbögen und seitliche Kephalogramme angefertigt. An den intraoralen Scanmodellen wurden die Tiefe der COS und die ausgleichende Kurve beurteilt. Mehrere dimensionale und kephalometrische Variablen des Zahnbogens wurden durch eine univariate Analyse überprüft. Anschließend wurde ein multiples lineares Regressionsmodell (schrittweise Vorwärtsselektion) erstellt, um festzustellen, welche Variablen signifikant mit den beiden Kurventiefen korrelierten.
UNASSIGNED: Im Mandibulabereich war die COS-Tiefe am mesiobukkalen Höcker des ersten Molaren am größten. Overjet, Breite des Unterkieferbogens und der Winkel zwischen Unterkiefer und Okklusionsebene korrelierten signifikant mit der COS-Tiefe (p < 0,05) und machten 33,1 % der Variation der Unterkiefer-COS aus. In der Maxilla lag der tiefste Punkt der kompensierenden Kurve auf dem distobukkalen Höcker des ersten Molaren. Unterkieferbogenumfang und Overbite korrelierten signifikant mit der kompensierenden Kurve in der Maxilla (p < 0,05) und erklärten 23,3 % der Variation.
UNASSIGNED: Overjet, Overbite, Winkel zwischen Unterkiefer und Okklusionsebene sowie Breite und Ausdehnung des Unterkieferbogens sollten bei der Rekonstruktion der Okklusionskurven in der klinischen kieferorthopädischen Behandlung und bei der prothetischen Versorgung berücksichtigt werden.

BACKGROUND: Presurgical plate therapy has been widely accepted as a treatment prior to palatal cleft closure. The effects of passive presurgical plate therapy on cleft morphology prior to single-stage unilateral cleft lip and palate (UCLP) repair were quantified.
METHODS: We compared the dimensions of cleft width and cleft area (true cleft and palatal cleft) measured preoperatively at 2 European cleft centers. Center A performed single-stage UCLP repair in 8-month-old infants without any presurgical orthopedic treatment. Center B initiated passive presurgical plate therapy immediately after the birth of the neonates, followed by single-stage UCLP repair at 8 months of age.
RESULTS: We included 28 patients with complete UCLP from Center A and 12 patients from Center B. The average anterior width of the true cleft before surgery was significantly smaller in infants at Center B than that in Center A (p = 0.001) with 95% confidence interval of (1.8, 5.7) mm, but the average posterior width was similar in the 2 groups. The mean presurgical true cleft area amounted to 106.8 mm2 (SD = 42.4 mm2) at Center A and 71.9 mm2 (SD = 32.2 mm2) at Center B, with a confidence interval for the difference being (9.8, 60.1) mm2. This corresponded to a 32.7% reduction of the true cleft area when passive presurgical plate therapy was used for the first 8 months of the infants\' life.
CONCLUSIONS: Passive presurgical plate therapy in UCLP significantly reduced the cleft area. Implications for the subsequent surgical outcome might depend on the surgical technique used.

BACKGROUND: The process of respiration is the primary factor of the posture of the jaws and tongue. Thus, a changed respiratory form like mouth breathing can change the posture of the head, jaw, and tongue. This, in turn, could change the equilibrium of pressure on the jaws and teeth thus affecting jaw growth and teeth positions. The influence of nasorespiratory function on craniofacial growth has stimulated interest and debate for more than a century. Mouth breathing is the reason for numerous orthodontic glitches such as a mouth breather\'s face evolving aberrantly because of of functional disruptions triggered by chronic airway obstruction. The relationship between nasorespiratory function and dentofacial development remains controversial despite the long-standing clinical concern of orthodontists, so there was a need to evaluate and compare the relationship between head posture, airway inadequacy, and craniofacial morphology in mouth breathers and nasal breathers.
METHODS: Forty patients were selected and divided equally into two groups: mouth breathers and nasal breathers. Patients were diagnosed as mouth breathers based on physical examination and a history of chronic allergic rhinitis, adenoid, and tonsil enlargement. Lateral cephalograms were taken for all patients in the natural head position (NHP) with the Planmeca Proline XC Dimax3 x-ray machine (Planmeca, Helsinki-Uusimaa, Finland). All lateral cephalograms were traced and analysis was done to check airway, head posture, and craniofacial morphology. Descriptive statistics were performed to obtain the means and standard deviation of all the sample sizes. Unpaired t test was performed between nasal breathers and mouth breathers to check and evaluate the relationship.
RESULTS: Mouth-breathing patients varied from nasal-breathing patients in airway adequacy and craniofacial morphology. A little, but not statistically significant, difference was seen in head posture between the two groups.
CONCLUSIONS: Early interception of mouth breathing in patients could be very helpful, as the postural changes in the mouth-breathing patients, if continued for a longer period of time, could be the reason for severe skeletal deformities as well as dental malocclusion.

OBJECTIVE: To reflect upon our non-surgical respiratory management by evaluating clinical outcomes regarding airway, feeding, and growth during the first year of life in patients with Robin Sequence.
METHODS: Prospective study.
METHODS: Sophia Children\'s Hospital, Rotterdam, the Netherlands.
UNASSIGNED: 36 patients with Robin Sequence who were treated between 2011 and 2021.
METHODS: Positional therapy and respiratory support.
METHODS: Data on respiratory outcomes included polysomnography characteristics and capillary blood gas values. Feeding outcomes were based on the requirement of additional tube feeding. Outcomes on growth were expressed as standard-deviation-scores (SDS) for weight-for-age (WFA) and height-for-age (HFA).
RESULTS: Twenty patients were treated with positional therapy (PT), whilst the other 16 patients required respiratory support. Twenty-two patients presented with non-isolated Robin Sequence (RS). During the first year of life, obstructive apnea hypopnea index decreased, oxygen levels enhanced, and capillary blood gas values improved. Eighty-six percent (31/36) experienced feeding difficulties, which completely resolved in 71% (22/31) during their first year of life. From start treatment, to stop treatment, to the age of 1 year, the SDS WFA worsened from -0.40 to -0.33 to -1.03, respectively.
CONCLUSIONS: Non-surgical respiratory treatment resulted in an improvement of respiratory outcomes to near normal during the first year of life in patients with RS. These patients often experience feeding difficulties and endure impaired weight gain up to 1 year of age, despite near normalization of breathing. The high prevalence of feeding difficulties and impaired weight for age indicate the urgency for early recognition and adequate treatment to support optimal growth.

OBJECTIVE: Masticatory function, including masticatory muscle activity and occlusal function, can be affected by craniofacial morphology. This study aimed to investigate the relationship between craniofacial morphology and masticatory function in participants who had completed orthodontic treatment at least two years before and had stable occlusion.
METHODS: Fourty-two healthy participants were prospectively enrolled and divided into three vertical cephalometric groups according to the mandibular plane angle. Masticatory muscle activity (MMA) in the masseter and anterior temporalis muscles was assessed using surface electromyography. The occlusal contact area (OCA) and occlusal force (OF), defined as occlusal function in this study, were evaluated using occlusal pressure mapping system. Masticatory muscle efficiency (MME) was calculated by dividing MMA by OF. The craniofacial morphology was analyzed using a lateral cephalogram. The masticatory function was compared using one-way analysis of variance. Pearson correlations were used to assess relationships between craniofacial morphology and masticatory function.
RESULTS: The hypodivergent group had the lowest MMAand the highest MME in the masseter (167.32 ± 74.92 µV and 0.14 ± 0.06 µV/N, respectively) and anterior temporalis muscles (0.18 ± 0.08 µV/N, p < 0.05). MMA in the masseter showed a positive relationship with mandibular plane angle (r = 0.358), whereas OCA (r = -0.422) and OF (r = -0.383) demonstrated a negative relationship (p < 0.05). The anterior temporalis muscle activity negatively correlated with ramus height (r = -0.364, p < 0.05).
CONCLUSIONS: Vertical craniofacial morphology was related to masticatory function. Hypodivergent individuals may have low MMA and high occlusal function, resulting in good masticatory muscle efficiency.
CONCLUSIONS: Hypodivergent individuals require careful consideration in orthodontic diagnosis and prosthetic treatment planning.

OBJECTIVE: Accurate nationwide epidemiological evidence is vital to study the seasonal, geographic, and ethnic influence on the trends of orofacial cleft prevalence in Kuwait.
METHODS: Data obtained from the National Center for Health Information and Ministry of Health Hospital digital records were reviewed retrospectively to identify patients with orofacial clefts (OFC) using the ICD-10 diagnostic codes. The Jonckheere-Terpstra test was used to assess the trend of birth prevalence across the different years. The associations of types of OFC with ethnic and geographic influences were tested with chi-square or Fisher\'s exact tests, while the strength of that association was tested with multi-nominal logistic regression.
RESULTS: Birth prevalence in Kuwait ranged from 0.75-2.55 per 1000 live births (0.73- 2.73 among Kuwaitis, 0.60-3.27 among non-Kuwaitis), with no statistically significant change observed during the past 28 years. The risk of unilateral cleft lip and palate was eight times higher during summer compared to Autumn, while the risk of cleft lip and palate remained lower during winter. Jahra (OR-7.76, CI- 1.51-39.80), Farwaneya (OR-6.65, CI- 1.34-33.06), and Hawalli (OR-6.72, CI- 1.26-35.98) governorates had higher odds of bilateral cleft lip when compared to Mubarak Alkabeer.
CONCLUSIONS: The study outcome is an indicator to improve patient care and customize healthcare infrastructure in the Ministry of Health. It also provides insight to develop projections of future needs. Future studies should focus on understanding the factors that might be a potential contributor to the seasonal change observed in the prevalence of OFC.

UNASSIGNED: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth.
UNASSIGNED: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7-24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements.
UNASSIGNED: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different.
UNASSIGNED: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

The present study aimed to evaluate the correlation between frontal sinus morphology and craniofacial morphology, and to investigate the effects of orthodontic treatment on the development of the frontal sinus in female adolescents (mean age: 13.9 ± 1.3 years). In total, 53 patients were recruited and underwent cephalography and computed tomography before and after orthodontic treatment. Of these patients, most had a bilaterally symmetrical fan-shaped frontal sinus without any fusion. The average size and volume of the frontal sinus before orthodontic treatment were 45.8 ± 12.3 mm in breadth, 29.8 ± 7.3 mm in height, 22.7 ± 5.1 mm in depth, and 5151.6 ± 2711.4 mm2 in volume. Sinus volume in patients with skeletal Class III malocclusion tended to be larger than that in patients with skeletal Class I and II malocclusion. Upon comparison with the pretreatment measurements, the sizes and volumes of the frontal sinus were significantly larger following orthodontic treatment, regardless of the skeletal pattern; however, since these changes were small, the increases in the size and volume of the frontal sinus may have been caused by pubertal growth and not orthodontic treatment. The clinical relevance of the frontal sinus remains controversial.

BACKGROUND: The objective of this study was to evaluate the applicability of distraction osteogenesis with or without collagen membrane coverage to approximate the bone surfaces surrounding alveolar defects in pigs.
METHODS: The sample comprised six pigs. One animal was control, and in the other five, alveolar bone defects were created and distraction osteogenesis was carried out to approximate adjacent bone surfaces in the defect site. Resorbable membranes were placed to cover the alveolar defects on one palatal side of the experimental animals. Radiographs were taken, and the histology was studied in each bone defect site at the 2nd, 9th, 16th, 23rd, and 46th days of healing.
RESULTS: The radiographs showed that the alveolar bone defects were successfully corrected. Initial osteogenesis was delayed, but bone bridge formation was complete in the membrane-covered samples at the 46th day of healing. In the other group, bone bridge formation was incomplete at the end of the study.
CONCLUSIONS: Distraction osteogenesis was effective in approximating transported bones to host bones. The resorbable membranes produced complete bone bridges in the approximation sites.

UNASSIGNED: This study aimed to evaluate if single nucleotide polymorphisms (SNPs) in runt-related transcription factor 2 (RUNX2) and bone morphogenetic protein 2 (BMP2) are associated with different craniofacial patterns. Furthermore, we also investigated if RUNX2 and BMP2 expression in the maxilla and mandible are differently expressed according to facial phenotypes and influenced by the SNPs in their encoding genes. Orthognathic patients were included.
UNASSIGNED: Lateral cephalometric radiographs were used to classify facial phenotypes based on Steiner\'s ANB and Ricketts\' NBa-PtGn angles. Bone samples from 21 patients collected during orthognathic surgery were used for the gene expression assays. DNA from 129 patients was used for genotyping the SNPs rs59983488 and rs1200425 in RUNX2 and rs235768 and rs1005464 in BMP2. The established alpha was 5%.
UNASSIGNED: A statistically significant difference was observed in the relative BMP2 expression in the mandible between Class I and III participants (P = 0.042). Homozygous GG (rs59983488) had higher RUNX2 expression (P = 0.036) in the mandible. In maxilla, GG (rs1200425) had a higher BMP2 expression (P = 0.038).
UNASSIGNED: In conclusion, BMP2 is expressed differently in the mandible of Class I and Class III participants. Genetic polymorphisms in RUNX2 and BMP2 are associated with their relative gene expression.