Uniformity of palatal volume and surface area in various malocclusions.

AIMS: To assess palatal volume, surface area and linear dimensions across sagittal and vertical components of malocclusion. METHODS: Pre-treatment cephalographs and dental casts of 178 non-growing patients (88 males, 90 females, age 25.81 ± 8.23 years) were used for classification in sagittal malocclusion groups: Class I (n = 48), Class II division 1 (n = 42), Class II division 2 (n = 40) and Class III (n = 48); and in vertical divergence groups based on the MP/SN angle: hypodivergent (n = 35), normodivergent (n = 95) and hyperdivergent (n = 48). Dental casts were scanned and palatal measurements recorded: palatal width, depth and interdental distances; palatal surface area (PSA, mm2 ) and volume (PV, mm3 ). A 3-way ANOVA was used to compare palatal dimensions across groups. Pearson product-moment correlations were employed to assess associations among variables. RESULTS: PSA and PV (in both sex groups) were not statistically significantly different across sagittal malocclusions and vertical patterns. Significant differences were depicted more among the vertical divergence groups than sagittal groups. Correlations between PSA and PV and palatal dimensions were low to moderate. Predictability of PSA and PV ranged between 15 and 18%. CONCLUSION: The finding of similar palatal volume and surface area, on average, across malocclusions possibly underscores the limitations of environmental influences within the inherited orofacial phenotype. The vertical facial pattern seems to be more interactive with palatal dimensions than sagittal relations. Studies of palatal changes following orthodontic and orthognathic treatments are warranted.

Novel genes linked to Class II Division 1 malocclusion with mandibular micrognathism.

INTRODUCTION: Mandibular micrognathism (MM) is an underdeveloped mandible resulting from complex interactions between genetic and environmental factors. Prior research focused mainly on the genetic determinants of mandibular retrognathism, not necessarily reflecting micrognathism, thus supporting the need to study MM. This study aimed to explore the inheritance pattern and identify the candidate genes involved in the development and familial transmission of MM. METHODS: Diagnosing probands with MM was based on clinical and lateral cephalometric data. The pedigrees were drawn for 11 identified families, 5 of whom accepted to undergo detailed data and biospecimen collection. These families included 15 MM and 13 non-MM subjects over 2-3 generations. The procedure involved the withdrawal of 5 mL of blood. Genomic DNA was isolated from blood cells to investigate protein-coding regions via whole exome sequencing. Standardized filtering steps were employed, and candidate genes were identified. RESULTS: Most of the pedigrees suggested a Mendelian inheritance pattern and segregated in an autosomal-dominant manner. One of the families, which also underwent biospecimen, displayed an X-linked inheritance pattern of the trait. Genetic screening disclosed 8 potentially novel genes (GLUD2, ADGRG4, ARSH, TGIF1, FGFR3, ZNF181, INTS7, and WNT6). None of the recognized exonic regions were previously reported. CONCLUSIONS: Eight novel genes were identified in association with MM in the largest number of families reported to date. The genes were X-linked in 1 family, a finding previously not observed in mandibular genetics.

Role of surgical hyoid bone repositioning in modifying upper airway collapsibility.

Background: Surgical hyoid bone repositioning procedures are being performed to treat obstructive sleep apnea (OSA), though outcomes are highly variable. This is likely due to lack of knowledge regarding the precise influence of hyoid bone position on upper airway patency. The aim of this study is to determine the effect of surgical hyoid bone repositioning on upper airway collapsibility. Methods: Seven anaesthetized, male, New Zealand White rabbits were positioned supine with head/neck position controlled. The rabbit's upper airway was surgically isolated and hyoid bone exposed to allow manipulation of its position using a custom-made device. A sealed facemask was fitted over the rabbit's snout, and mask/upper airway pressures were monitored. Collapsibility was quantified using upper airway closing pressure (Pclose). The hyoid bone was repositioned within the mid-sagittal plane from 0 to 5 mm (1 mm increments) in anterior, cranial, caudal, anterior-cranial (45°) and anterior-caudal (45°) directions. Results: Anterior displacement of the hyoid bone resulted in the greatest decrease in Pclose amongst all directions (p = 0.002). Pclose decreased progressively with each increment of anterior hyoid bone displacement, and down by -4.0 ± 1.3 cmH2O at 5 mm. Cranial and caudal hyoid bone displacement did not alter Pclose (p > 0.35). Anterior-cranial and anterior-caudal hyoid bone displacements decreased Pclose significantly (p < 0.004) and at similar magnitudes to the anterior direction (p > 0.68). Conclusion: Changes in upper airway collapsibility following hyoid bone repositioning are both direction and magnitude dependent. Anterior-based repositioning directions have the greatest impact on reducing upper airway collapsibility, with no effect on collapsibility by cranial and caudal directions. Findings may have implications for guiding and improving the outcomes of surgical hyoid interventions for the treatment of OSA.

Semantic Segmentation of Maxillary Teeth and Palatal Rugae in Two-Dimensional Images.

The superimposition of sequential radiographs of the head is commonly used to determine the amount and direction of orthodontic tooth movement. A harmless method includes the timely unlimited superimposition on the relatively stable palatal rugae, but the method is performed manually and, if automated, relies on the best fit of surfaces, not only rugal structures. In the first step, motion estimation requires segmenting and detecting the location of teeth and rugae at any time during the orthodontic intervention. Aim: to develop a process of tooth segmentation that eliminates all manual steps to achieve an autonomous system of assessment of the dentition. Methods: A dataset of 797 occlusal views from photographs of teeth was created. The photographs were manually semantically segmented and labeled. Machine learning methods were applied to identify a robust deep network architecture able to semantically segment teeth in unseen photographs. Using well-defined metrics such as accuracy, precision, and the average mean intersection over union (mIoU), four network architectures were tested: MobileUnet, AdapNet, DenseNet, and SegNet. The robustness of the trained network was additionally tested on a set of 47 image pairs of patients before and after orthodontic treatment. Results: SegNet was the most accurate network, producing 95.19% accuracy and an average mIoU value of 86.66% for the main sample and 86.2% for pre- and post-treatment images. Conclusions: Four architectural tests were developed for automated individual teeth segmentation and detection in two-dimensional photos that required no post-processing. Accuracy and robustness were best achieved with SegNet. Further research should focus on clinical applications and 3D system development.

Oral health status in a Lebanese geriatric population.

Background: The sustained growth of older people and the epidemiological shift from communicable to chronic health problems have attracted increased attention to geriatric wellbeing, including oral health. Aims: To evaluate the oral health of urban community-dwelling older people and identify their priority oral health needs. Methods: We recruited 352 adults aged ≥ 65 years in 2015 from social organizations and primary healthcare centres in Beirut and its suburbs. Older people underwent dental examination including the decayed, missing and filled teeth (DMFT) score, gingival health [plaque index (PI) and Periodontal Screening and Recording (PSR)], and dental functional units (FUs). Sociodemographic data were gathered through a structured questionnaire in a face-to-face interview. The participants were stratified into 3 age groups, and according to restoration with partial, complete and no dentures. Statistical analyses included the Mann-Whitney, Kruskal-Wallis and χ2 tests to explore the oral health status by sociodemographics. Results: Missing teeth contributed most to high DMFT score. Mean PI and root caries indices were high. Mean FU scores were low, but higher in women and in complete denture wearers. Lower numbers of remaining mandibular anterior and maxillary posterior teeth, higher DMFT scores, but better periodontal status (lower PSR scores) were found in the older age groups. The more educated participants exhibited the healthier scores. Conclusion: We observed poor oral health, particularly missing teeth and low FUs, in older people, warranting interventions to integrate oral health within the scope of geriatric general health.

Morphometric analysis of palatal rugae in different malocclusions.

OBJECTIVES: Studies of the association between palatal rugae (PR) and malocclusion are scarce. While unstable following treatment such as rapid maxillary expansion, we hypothesized that PR differ among malocclusions because of genetic determination but also different environmental conditions during development. Our goal was to assess the possible association between PR morphometric measurements and both sagittal and vertical characteristics of malocclusion. METHODS: Maxillary pretreatment dental casts of 243 nongrowing individuals (115 males, 128 females, age 25.5 ± 7.5 years) were laser scanned (Perceptron ScanWorks® V5, Hallam VIC, Australia); angular and linear measurements of the first three PR were recorded in transverse and anteroposterior directions. Cephalometric measurements were obtained from corresponding digitized lateral cephalograms. Statistics included analyses of variance to compare PR measurements among sagittal (class I, class II divisions 1 and 2, class III) and vertical (hypodivergent, normodivergent, hyperdivergent) malocclusion groups and the Pearson correlations among PR dimensions and cephalometric measurements. RESULTS: PR measurements were statistically different between malocclusions, especially with respect to vertical patterns. A majority of transverse and anteroposterior rugae measurements were greatest in class II division 2 subjects. PR were more anteriorly directed in hypodivergent than hyperdivergent groups; the transverse separation between opposing rugae points was smaller. Correlations were generally low. CONCLUSIONS: The findings suggest the possibility for PR to adapt to environmental effects in developing malocclusions, mostly in the class II division 2 phenotype. This premise reinforces the need to explore in longitudinal studies the long-term environmental influences on rugae superimposed on their genetically determined morphological pattern.

Barriers to the use of dental services by children in Lebanon and association with parental perception of oral health care.

BACKGROUND: Oral health is important to general health but use of dental services varies considerably, particularly for children. AIMS: We aimed to determine factors associated with parents' use of dental services for their children in Lebanon, and their perception of dental care relative to medical care. METHODS: A convenience sample of public and private schools in Beirut was selected between January and May 2013. Parents of children in grades 2-6 (aged 7-12 years) were invited to complete a questionnaire covering socioeconomic characteristics and use of dental services. Logistic regression analysis was used to assess the relationship between use of dental services, and parents' socioeconomic characteristics and awareness and perceptions of dental services. RESULTS: The parents of 316 children returned the questionnaire. Most children (72.8%) had been taken to the dentist in the past year, mainly for emergency care. Most parents (78.2%) considered dental care as important as or more important than medical care, and 89.9% were willing to contribute to dental insurance. Use of dental services was significantly associated with: older age of the parent (odds ratio, OR = 1.04; 95% confidence interval, CI: 1.02-1.06); awareness of dental care centres offering affordable treatment (OR = 3.18; 95% CI: 1.52-6.68); and children being in private schools (OR = 2.00, 95% CI: 1.08-3.95). It was negatively associated with > 4 children in the family compared with 1 child (OR = 0.18; 95% CI: 0.04-0.81). CONCLUSION: Barriers to dental care for children were mostly related to economic factors.

Potential and limitations of orthodontic biomechanics: recognizing the gaps between knowledge and practice.

The perennial goals of efficient biomechanics are to obtain more controlled and faster movement and using more discrete appliances. The most recent technological advances have buttressed these goals. Temporary anchorage devices have revolutionized orthodontic practice and loom as a solid cornerstone of orthodontic science, along with the use of light forces, facilitated by "smart" archwires for optimal tooth movement. Accelerated tooth movement with decortication has been successful because of decreasing the resistance of cortical bone but micro-osteoperforation has not matched the same results. Clear aligners and preprogrammed regular or lingual appliances reflect the importance of three-dimensional technology in appliance design based on treatment outcome. These mechanical developments have inched the science closer to the traditional goals, but advances lack regarding their enhancement by biomaterials in a system where the physical stimulus is exerted on the teeth but the expression of tooth displacement is through the biological processes within the surrounding tissues. In this article, present tenets, applications, and advances are explored along with the gaps between knowledge and practice and the possibilities to bridge them. Anchorage control remains the major widely used development but slower is the development of faster noninvasive treatment.

Overcoming compact bone resistance to tooth movement.

The general boundaries to tooth movement are within the adjacent compact and trabecular bones, gingiva, mucosa, and muscular envelope. Findings from finite element analysis of maxillary posterior teeth distalization against mini-implants suggest that stiff outer and interproximal compact bone resists tooth movement, regardless of bone thickness, and that teeth should be steered away from this bone during orthodontic treatment. However, individual variation in the tooth-bone interface dictates the course and outcome of treatment, offering the basis for inferences on the limits of mini-implant anchorage and the presumed influence of the regional acceleratory phenomenon through decortication and microperforation, 2 modalities advocated to effect faster tooth movement.

Effect of force direction and tooth angulation during traction of palatally impacted canines: A finite element analysis.

INTRODUCTION: Treatment of a palatally impacted canine (PIC) is associated with demanding anchorage control, increased treatment duration, and undesirable side effects. Accurate PIC localization and force application impact treatment success. The objective of this research was to determine the stresses on the PIC when subjected to initial force activation in various directions (buccal, vertical, and distal) and relative to impaction severity. METHODS: Thirty PICs from 21 scans underwent finite element modeling. A prototype 3D model was reconstructed and segmented into its anatomic components. Each PIC was precisely positioned in the prototype model according to impaction position. Stresses in response to a (1.0 N) force in the distal, vertical, and buccal directions were evaluated at different levels of the root (apical, middle, and cervical). RESULTS: Distal and buccal forces yielded higher stress (6.64 and 6.41 kPa, respectively) than the vertical force (5.97 kPa) on the total PIC root and the apical and cervical root levels, but not at midroot. Statistically significant differences between severity groups were found mostly at the apical level among all force directions, except between distal and buccal forces in the higher severity group. In this group, stress was greatest at the cervical level with the buccal force significantly different from the stresses generated by either the distal or the vertical force. CONCLUSIONS: Vertical forces generated the lowest stresses. Differentially distributed stresses over the root reflected an initial tipping movement. Greater cervical stresses from the buccal force indicate resistance to movement, suggesting treatment initiation with vertical and distal forces over buccal forces, particularly with severely inclined canines.

Evaluation of commonly used occlusal indices in determining orthodontic treatment need.

OBJECTIVE: The main objective of this study was to validate commonly used occlusal indices in measuring treatment need, irrespective of their original objective: Index of Orthodontic Treatment Need (IOTN) that includes a dental health component (DHC) and an aesthetic component (AC), Peer Assessment Rating (PAR) index, Index of Complexity, Outcome, and Need (ICON), Discrepancy Index (DI), and Facial Aesthetic Index (FAI). METHODS: The dental casts, x-rays, and photographs of 101 participants were randomly selected among patients whose orthodontic treatment was completed. The indices were validated against the panel assessments of four experts using the receiver operating characteristic curve analysis. The area under the curve (AUC) helped to determine their optimal cut-off points. RESULTS: The raters exhibited an excellent level of inter-rater reliability in assessing need scores [intra-class correlation coefficients (ICC) = 0.85]. The DHC, AC, ICON, and PAR demonstrated 'good' diagnostic properties (AUC = 0.85, 0.84, 0.83, and 0.82, respectively). Adding the AC and the DHC into a combined index score [our proposed Combined Index of Orthodontic Treatment Need (CIOTN)] yielded the strongest correlation with need (r = 0.79) and the highest AUC value of 88 per cent with 91 per cent sensitivity and 71 per cent specificity. The DI had poor discriminating abilities (AUC = 0.69), however, its dental component was substantially better (AUC = 0.81). The supplemental FAI did not enhance the correlation of indices with need. CONCLUSION: The DHC, AC, ICON, PAR, and only the dental component of the DI reliably captured treatment need. The newly combined CIOTN had superior diagnostic properties than its components and all other indices, probably because of the cumulative values of its components. The FAI could not be validated as a supplemental measure of treatment need.

Differentiation between maxillary and malar midface position within the facial profile.

AIMS: To define midfacial position differentiating maxillary and zygomatic regions and to evaluate the corresponding cephalometric characteristics discerning midfacial flatness and fullness. MATERIAL AND METHODS: A total of 183 pretreatment lateral cephalometric radiographs of non-growing orthodontic patients (age 25.98 ± 8.43 years) screened at our university orthodontic clinic. The lateral cephalographs of the orthodontic patients were stratified in four groups: flat, normal toward flat, normal toward full, full,according to distances from nasion and sella to points J and G (NJ, SJ, NG and SG). J is the midpoint of the distance connecting orbitale to point A, and G the center of the triangle connecting orbit, key ridge and pterygomaxillary fissure. Statistics included the Kendall tau-b test for best associations among measurements. RESULTS: All measurements were statistically significantly different between flat and full groups. The highest associations were between NJ and SJ (τb = 0.71; p < 0.001) and NG and SG (τb = 0.70; p < 0.001). Flat midfaces were characterized by canting of the cranial base and palatal plane, hyperdivergent pattern and maxillary retrognathism. The opposite was true for fuller midfaces. CONCLUSION: Midface skeletal location was assessed differentially in the naso-maxillary and malo-zygomatic structures differentially. Craniofacial characteristics were identified according to this stratification, indicating the potential for application in facial diagnosis and need for testing on 3D cone-beam computed tomography images.

Two distalization methods compared in a novel patient-specific finite element analysis.

INTRODUCTION: Orthodontic mini-implants aid in the correction of distocclusions via direct anchorage (pull from mini-implant to teeth) and indirect anchorage (teeth pulled against other teeth anchored by the mini-implant). The aim of this study was to compare stress levels on the periodontal ligament (PDL) of maxillary buccal teeth in direct and indirect distalization against orthodontic mini-implants and accounting for individual variation in maxillary anatomy and biomechanical characteristics of the compact bone. METHODS: A 3D model of the maxilla containing the different components (teeth, PDL, trabecular and cortical bones) was generated from a computed tomographic scan. Cortical bone was divided into several areas according to previously defined zones. Bone stiffness and thickness data, obtained from 11 and 12 cadavers, respectively, were incorporated into the initial model to simulate the individual cortical bone variation at the different locations. Subsequently, a finite element analysis was used to simulate the distalization modalities. RESULTS: Stresses at the buccal, palatal, mesial, and distal surfaces were significantly different between adjacent teeth under stiffness but not thickness variation. In both distalization modalities, low or no significant correlations were found between stress values and corresponding cortical bone thicknesses. High significant and inverted correlations were observed at the first molar between stress amounts and cortical bone stiffness (direct modality: -0.68 < r < -0.72; indirect modality: -0.80 < r < -0.82; P <0.05). CONCLUSIONS: With the use of a novel finite element approach that integrated human data on variations in bone properties, findings suggested that cortical bone stiffness may influence tooth movement more than bone thickness. Significant clinical implications could be related to these findings.

Three novel genes tied to mandibular prognathism in eastern Mediterranean families.

INTRODUCTION: Mandibular prognathism (MP) is subject to major polygenic influence and segregates within families in autosomal dominance with variable expressivity and incomplete penetrance. We aimed to identify the inheritance pattern and genes and loci involved in the development of MP in Mediterranean families and to evaluate the dentoskeletal characteristics of affected individuals. METHODS: Fifty-one eastern Mediterranean families with individuals affected by MP were identified. Data and biospecimens were collected from 14 of the families, including clinical examination, lateral cephalography (on subjects with Class III malocclusion), and 5 mL blood drawn from consenting affected and nonaffected relatives. Next-generation sequencing (NGS) was performed on 8 families (7 Lebanese, 1 Lebanese/Syrian), including large numbers of affected individuals over many generations and severe conditions, with the use of whole-exome sequencing. RESULTS: Most pedigrees suggested autosomal-dominant inheritance with an equal number of affected male and female individuals. Affected individuals had macrognathic and prognathic mandibles with dentoalveolar compensation. Genetic screening did not correspond with previously reported MP-linked genes, but yielded 3 novel genes (C1orf167, NBPF8, NBPF9) on chromosome 1 potentially responsible for mandibular development and macrognathism. CONCLUSIONS: In this first genetic study with the use of NGS on the largest reported number of families with MP, novel genes (C1orf167, NBPF8, NBPF9) were associated with familial MP in the eastern Mediterranean population.

Finite element analysis of stresses on adjacent teeth during the traction of palatally impacted canines.

OBJECTIVE: To evaluate stresses on maxillary teeth during alignment of a palatally impacted canine (PIC) under different loading conditions with forces applied in vertical and buccal directions. MATERIALS AND METHODS: A three-dimensional finite element model of the maxilla was developed from a cone beam computed tomographic scan of a patient with a left PIC. Traction was simulated under different setups: (1) palatal spring extending from a transpalatal bar (TPB) anchored on the first molars (M1) and alternatively combined with different archwires (0.016 × 0.022-inch; 0.018 × 0.025-inch) with and without engaging second molars and (2) a buccal force against 0.018-inch, 0.016 × 0.022-inch, and 0.018 × 0.025-inch archwires with and without engaging the left lateral incisor (I2). RESULTS: Without fixed appliances, stresses were assumed by M1; with fixed appliances, stresses were distributed on all teeth, decreasing mesially toward the midline. Direct buccal pull exerted most stress on neighboring I2 (19-20% with different wire sizes) and first premolar (12-17%), decreasing distally, along a similar pattern with different archwire sizes. When I2 was bypassed, stresses on adjacent teeth increased only by 3-6%. Higher stresses occurred with the lighter round wire. CONCLUSIONS: This first research on stresses on adjacent teeth during PIC traction provided needed quantitative data on the pattern of stress generation, suggesting the following clinical implications: use of distal-vertical pull from posterior anchorage (TPB) as initial movement and when using a buccal force, bypassing the lateral incisor and using heavier wires that would minimize side effects.

Palatally impacted canines: A new 3-dimensional assessment of severity based on treatment objective.

INTRODUCTION: The severity of a palatally impacted canine (PIC) is gauged radiographically on 2-dimensional and 3-dimensional positional components: eg, angulation and height. We hypothesized that the position of a PIC relative to its virtual alignment in the arch is a better indication of impaction severity and treatment requirements. The aims of this research were to evaluate variations in PIC location on 3-dimensional images and to determine positional components associated with impaction severity. METHODS: Linear and angular measurements of 38 PICs from 28 cone-beam computed tomography scans were made on the panoramic, coronal, sagittal, and axial sections. Measurements included angulation of the PIC to the virtually aligned canine, midline, and palatal plane; and distances between cusp tip and apex to various reference planes-eg, occlusal and midpalatal. Statistical assessments comprised t tests for group comparisons based on PIC and virtually aligned canine severity (cutoff at 30°) and Pearson product moment correlations for associations among variables. RESULTS: Angulations of the PIC to the virtually aligned canine were 32.5° ± 15.5° (range, 9°-59°) and 19.6° ± 6.9° and 45.37° ± 9.6°, respectively, in the less severe and more severe groups (P <0.001). Group differences were significant (0.023 

Chin-throat anatomy: Normal relations and changes following orthognathic surgery and growth modification.

OBJECTIVES: To determine if a new facial line (T), tangent to the throat, intersects the mandibular border in anterior (ANT) and posterior (POST) parts in proportions varying with facial configuration, and to evaluate the association between chin projection and throat inclination and the potential for the T-line to reflect this association. MATERIALS AND METHODS: Measurements on profile photographs and cephalograms of 135 adults (aged 18-50 years)-45 each of Class I, II, and III (CI, CII, CIII) malocclusions-included ANT and POST, chin-throat (CTA), and mento-cervical (MCA) angles. Pre- and posttreatment measurements were compared in two subgroups (n = 25 each) of CII and CIII orthognathic surgery patients and in CII, division 1 early-treatment patients (n = 63). Statistics included analysis of variance and t-test for group differences, and Pearson correlation for associations among variables. RESULTS: ANT was nearly equal to POST in CI (50.99%) and CIII (51.86%) subjects and shorter in CII (36.01%) subjects. CTA and MCA were greater in CII profiles and smaller in CIII profiles. Significant differences (P < .0001) were observed for ANT, POST, CTA, and MCA between Classes I/II and II/III and for MCA between Classes II/III (P = .016). High correlations were noted between ANT and CTA in Classes I (r = -0.83), II (r = -0.73), and III (r = -0.68). In surgically treated patients, posttreatment measurements approached CI values. In the early-treatment group, ANT increased but remained smaller than POST; CTA decreased by nearly 13%. CONCLUSIONS: Chin-throat relations and chin extension are associated and require routine assessment in terms of diagnosis and treatment outcome. A practical tool to assess chin-throat relationship, the T-line bisects the mandibular body nearly equally in Class I faces.

Instability of palatal rugae following rapid maxillary expansion.

BACKGROUND: Existing evidence on changes of the palatal rugae following rapid maxillary expansion (RME) is scarce and inconclusive, particularly immediate post-expansion changes in three-dimensional assessments. OBJECTIVES: Our aims were to assess the dimensional stability of the palatal rugae in the antero-posterior and transverse dimensions following RME treatment, as well as the three-dimensional changes in palatal volume and area. MATERIAL AND METHODS: The sample consisted of the dental casts of 30 adolescents (16 males; 14 females, age 11.46 ± 1.42 years) who underwent RME. The models, available at T1 (pretreatment) and T2 (immediately after expansion) were scanned using a laser scanning system. Various parameters were recorded including individual ruga transverse and antero-posterior linear and angular measurements; palatal dimensions (width, length, volume, surface area, vault depth/height); and dental characteristics (interincisor, intercanine, interpremolar, and intermolar distances). Statistical analyses included paired t-tests for group comparisons, and Pearson moment product for associations among variables. RESULTS: Palatal rugae were altered by RME in all dimensions in both linear and angular measurements, almost equally on right and left sides, albeit the average linear changes were about 1 mm. Correlation coefficients among rugal and dental measures suggested an association between rugae changes and the underlying bony movements. Except for the first rugae that had higher correlations to the intercanine width, the correspondence of changes seems to be asymmetric, thus not precisely predictable. CONCLUSIONS: The results suggest a variable trend in the rugae response to expansion, likely reflecting the constitutional asymmetric pattern or nature of pairs of rugae.

Centennial inventory: the changing face of orthodontics.

The American Journal of Orthodontics and Dentofacial Orthopedics celebrates its centennial, safeguarded by the nearly 115-year-old American Association of Orthodontists. This journey witnessed the rise and demise of various developments, concepts, and procedures, while basic knowledge is still needed. Various periods can be defined in the past century, but the goals remain to obtain more accurate diagnosis through precise anatomic imaging, more controlled and faster tooth movement, more discreet appliances, and the balance of esthetics, function, and stability. The most recent technologic advances have buttressed these goals. Cone-beam computed tomography has brought 3-dimensional assessment to daily usage, albeit the original enthusiasm is tempered by the risk of additional radiation. Temporary anchorage devices or miniscrews have revolutionized orthodontic practice and loom as a solid cornerstone of orthodontic science. Decortication and microperforation promise to speed up tooth displacement by stimulating vascularization. The concept of the regional acceleratory phenomenon has touched upon even the timing of orthognathic surgery. The burden of esthetic appliances remains, with the demand for "cosmetic" appliances and clear aligners. Have these developments changed the face of orthodontics? Have we engaged in another turn wherein certain treatment modalities may fade, while others join mainstream applications? These questions are addressed in this essay on the challenges, promises, and limitations of current orthodontic technology, enhancement of biologic response, and personalized treatment approaches.

Coenraad F. A. Moorrees: Journey to the top of Mons Scolaris (Mount Scholar).

Coenraad F. A. Moorrees was a pioneer in orthodontic education and research. He was the first academic leader to merge clinical and research requirements in a 3-year residency. Beyond his lifelong association with the Harvard School of Dental Medicine and the Forsyth Dental Center (now the Forsyth Institute), his scholarly impact has reached worldwide through his multifaceted publications, but perhaps more potently through his postdoctoral fellows, 52% of whom achieved professorial ranks at academic institutions, and 15% became heads of orthodontic departments. His scholarly productivity cut across various components of facial growth and development, including the critical consideration of the soft tissue profile in evaluating the total face and the assessment of constitutional and psychobiologic panels in diagnosis and treatment of the individual patient. His investigations on dental development yielded cornerstone knowledge that was readily transferred to clinical applications. His contributions in various organizations included extended service for the prestigious National Institute for Dental Research, which oversees the most important research output in the United States. Numerous national and international recognitions were bestowed on him. He combined in his person the attributes of "renaissance educator" and "citizen of the world," reflecting a unique combination of science and humanity.