Overexpression of αCGRP promotes osteogenesis of periodontal ligament cells by regulation of YAP signaling.

Human periodontal ligament cells (hPDLCs) are considered as an ideal cell type for periodontal tissue engineering as hPDLCs own mesenchymal stem cell-like properties. Additionally, it is suggested that α-calcitonin gene-related peptide (αCGRP) plays a pivotal role in the pathogenesis of periodontitis. However, the specific role of αCGRP on the regulation of alveolar bone regeneration which is essential for treatment of periodontitis remains unclear. In this study, lentiviral αCGRP expression vector was first transfected into hPDLCs. αCGRP expression and the osteogenesis-related gene (ALP, RUNX2, OCN, and BSP) expressions were detected. The results showed that expressions of osteogenic phenotypes were upregulated in αCGRP-transfected hPDLCs combined with an increased expression of Yes-associated protein (YAP), which is the key downstream effectors of Hippo pathway. Our observations suggest that αCGRP-mediated hPDLCs' osteogenesis might relate with the activity of YAP signaling. These observations may reflect intrinsic functions of αCGRP in hPDLCs' osteogenesis and its promising role in the treatment of bone deficiency in periodontal regeneration.

Growth-dependent phenotype in FasL-deficient mandibular/alveolar bone.

FASL (CD178) is known for its role in triggering apoptosis, mostly in relation with immune cells but additional functions have been reported more recently, including those in bone development. Examination of postnatal FasL-deficient mice (gld) showed an increased bone deposition in adult mice when compared with wild types. However, a different phenotype was observed prenatally, when the gld bone was underdeveloped. The aim of the following investigation was to evaluate this indication for an growth-dependent bone phenotype of gld mice and to search for the 'switch point'. This study focused on the mandibular/alveolar bone as an important structure for tooth anchorage. In vivo micro-computed tomography (CT) analysis was performed at different stages during the first month (6, 12 and 24 days) of postnatal bone development. In 6-day-old gld mice, a decrease in bone volume/tissue volume (BV/TV), trabecular thickness and trabecular number was revealed. In contrast, the 12-day-old gld mice showed an increased BV/TV and trabecular thickness in the alveolar bone. The same observation applied for bone status in 24-day-old gld mice. Therefore, changes in the bone phenotype occurred between day 6 and 12 of the postnatal development. The switch point is likely related to the changing proportion of bone cells at these stages of development, when the number of osteocytes increases. Indeed, the immunohistochemical analysis of FASL localized this protein in osteoblasts, whereas osteocytes were mostly negative at examined stages. The impact of FASL particularly on osteoblasts would agree with an earlier in vivo observed effect of FASL deficiency on expression of Mmp2, typical for osteoblasts, in the gld mandibular/alveolar bone. Notably, an age-dependent bone phenotype was reported in Mmp2-deficient mice.

Evaluating of Platelet-Rich Fibrin in the Treatment of Alveolar Cleft With Iliac Bone Graft By Means of Volumetric Analysis.

The purpose of this study was to evaluate the efficiency of platelet-rich fibrin usage in the treatment of alveolar cleft with iliac bone graft by means of volumetric analysis. In this study, 22 patients with alveolar clefts-including 13 unilateral and 9 bilateral-were treated with anterior iliac crest bone grafts. Patients were divided into 2 groups as control (group A) and platelet-rich fibrin (group B) groups. Cone beam computed tomography (CBCT) scans were obtained preoperatively and 6 months postoperatively. Three-dimensional reconstructions of CBCT images were created by using Mimics software. Preoperative alveolar cleft volume and postoperative newly formed bone volume were assessed volumetrically. The percentages of preoperative alveolar cleft volume ranged from 0.51 to 2.04 cm, with a mean volume of 0.98 ±â€Š0.33 cm. The percentages of newly formed bone in group B ranged from 50.70% to 80.09%, with a mean percentage of 68.21 ±â€Š10.80%. In Group A, the percentages of bone formation ranged from 47.02% to 79.23%, with a mean percentage of 64.62 ±â€Š9.49%. Platelet-rich fibrin can be used in the treatment of alveolar cleft with corticocancellous bone graft harvested from the anterior iliac crest, but in this study, there was no statistically significant difference between the groups for postoperative newly formed bone volume (P > 0.05).

Modified Activation Technique for Nasal Stent of Nasoalveolar Molding Appliance for Columellar Lengthening in Bilateral Cleft Lip/Palate.

Bilateral cleft lip/cleft palate is associated with nasal deformities typified by a short columella. The presurgical nasoalveolar molding (NAM) therapy approach includes reduction of the size of the intraoral alveolar cleft as well as positioning of the surrounding deformed soft tissues and cartilages. In a bilateral cleft patient, NAM, along with columellar elongation, eliminates the need for columellar lengthening surgery. Thus the frequent surgical intervention to achieve the desired esthetic results can be avoided. This article proposes a modified activation technique of the nasal stent for a NAM appliance for columellar lengthening in bilateral cleft lip/palate patients. The design highlights relining of the columellar portion of the nasal stent and the wire-bending of the nasal stent to achieve desirable results within the limited span of plasticity of the nasal cartilages. With this technique the vertical taping of the premaxilla to the oral plate can be avoided.

Relationship Between Orthodontic Force Applied by Monoblock and Salivary Levels of Alkaline Phosphatase and Lactate Dehydrogenase Enzymes.

AIM: The current study was aimed to determine the relationship between the orthodontic force applied by monobloc and the salivary level of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) enzymes, considering the time factor after insertion of the appliance and whether there is a correlation between these enzymes. MATERIALS AND METHODS: A sample of 28 growing patients requiring orthodontic treatment with myofunctional appliance (Monoblock) was taken for the current study with an age range 9 to 12 years,all patients had Angle's class II division 1 mal-occlusion with no or mild crowding, the sample was selected using simple random sampling. Only 16 subjects (10 males and 6 females) were included who follow certain inclusion criteria. Unstimulated saliva was collected from the patients before monoblock insertion, then 1 hour after insertion, followed by 14 days and 28 days. Salivary levels of ALP and LDH were measured using a spectrophotometer and compared with the base line. RESULTS: The results revealed that ALP and LDH levels increased with increasing time after monoblock insertion, and there was the statistically insignificant difference after 1-hour post-insertion for ALP enzyme level, but highly significant after 14 and 28 days. While for LDH level,there was the statistically significant difference after 1-hour post-insertion, but highly significant difference after 14 and 28 days post-insertion. In this regard to the relation between salivary ALP and LDH enzymes levels at different time intervals, showed that there were no significant correlations between the enzymes using Pearson's correlation test. CONCLUSION: The ALP and LDH salivary enzymes activity is affected by mechanical forces generated by monobloc activator and these enzymes activities can also be increased during the rapid growth phase of childhood such as late infancy and early puberty where the age of subjects was selected in the current study. CLINICAL SIGNIFICANCE: The determination of ALP and LDH salivary enzymes activities during the skeletal maturity is crucial for the success of myofunctional monobloc treatment; therefore, saliva can be used as a noninvasive diagnostic tool for determination of chemical biomarkers for detection of bone remodeling process during myofunctional monoblock treatment Keywords: Alkaline phosphatase (ALP), Lactate dehydrogenase (LDH), Monoblock, Orthodontic force, Salivary levels.

Effects of vascular formation during alveolar bone process morphogenesis in mice.

The alveolar bone process is the thickened ridge of bone that bears the teeth and is known to have dynamic functional interactions with surrounding tissues. However, the detailed morphological changes that occur during alveolar bone process development and the underlying molecular mechanisms behind this morphogenesis have not been elucidated. In this study, we examined the detailed morphological changes of the alveolar bone process during mouse development using HE and MTC staining. In addition, we evaluated the precise localization pattern of various signaling molecules involved in blood vessel formation including CD31, α-SMA, VEGF, periostin, and TGF-ß. Innervation of the alveolar bone process was examined following injection of the nerve terminal dye AM1-43. The morphological and immunohistochemical data suggested that there is an intimate relationship between alveolar bone process development and blood vessel formation. To more closely examine the role of blood vessels in alveolar bone process formation, we microinjected mice with a clinically available anti-VEGF antibody, bevacizumab, at PN5 and analyzed the effects 5 days later. Compared to the control animals, anti-VEGF treated animals showed a disruption of the integration of bony tissues to form the alveolar bone process structures, which should contain the periodontal ligaments. Based on these data, we conclude that specific morphogenesis of the alveolar bone process is closely associated with blood vessel formation.

Epigenetic gene regulation by histone demethylases: emerging role in oncogenesis and inflammation.

Histone N-terminal tails of nucleosomes are the sites of complex regulation of gene expression through post-translational modifications. Among these modifications, histone methylation had long been associated with permanent gene inactivation until the discovery of Lys-specific demethylase (LSD1), which is responsible for dynamic gene regulation. There are more than 30 members of the Lys demethylase (KDM) family, and with exception of LSD1 and LSD2, all other KDMs possess the Jumonji C (JmjC) domain exhibiting demethylase activity and require unique cofactors, for example, Fe(II) and α-ketoglutarate. These cofactors have been targeted when devising KDM inhibitors, which may yield therapeutic benefit. KDMs and their counterpart Lys methyltransferases (KMTs) regulate multiple biological processes, including oncogenesis and inflammation. KDMs' functional interactions with retinoblastoma (Rb) and E2 factor (E2F) target promoters illustrate their regulatory role in cell cycle progression and oncogenesis. Recent findings also demonstrate the control of inflammation and immune functions by KDMs, such as KDM6B that regulates the pro-inflammatory gene expression and CD4+ T helper (Th) cell lineage determination. This review will highlight the mechanisms by which KDMs and KMTs regulate the target gene expression and how epigenetic mechanisms may be applied to our understanding of oral inflammation.

Dentoalveolar Effects of Early Orthodontic Treatment in Patients With Cleft Lip and Palate.

No agreement exists on the most appropriate timing of orthodontic treatment in patients with cleft lip and palate. The aim of this study is to investigate the effect of early orthodontic treatment on development of the dental arches and alveolar bone.A dental casts analysis was performed on 28 children with cleft lip and palate before orthodontic treatment (T0; mean age, 6.5 ±â€Š1.7) and at the end of active treatment (T1; mean age, 9.2 ±â€Š2.1 years). The considered variables were: intercanine and intermolar distances; dental arch relationships, evaluated according to the modified Huddart/Bodenham system.The study group was divided into 2 samples according to the age at T0: Group A (age < 6 years) and Group B (age ≥ 6 years). A statistical comparison of the treatment effects between the 2 samples was performed.Patients in Group A exhibited a greater increase of intercanine distance (8 mm versus 2.7 mm; P<0.001), intermolar distance (7.2 mm versus 5 mm; P = 0.06), and Huddart/Bodenham score (7.1 versus 3; P < 0.05) when compared with patients in Group B.Early orthodontic treatment strongly improved the dental arch relationship, since subjects starting the therapy before the age of 6 had a better response in terms of anterior maxillary expansion.

Newly Formed Bone Induced by Recombinant Human Bone Morphogenetic Protein-2: A Histological Observation.

PURPOSE: To observe, histologically, bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) in onlay grafted and sinus lifted alveolaris. MATERIAL AND METHODS: Eighteen patients were treated with rhBMP-2 at concentration 1.5 mg/mL with an absorbable collagen sponge (ACS). The treated bone was harvested with small trephine bur at 5 or 7 months after surgery for the micro Computer Scanning (CT) and light microscopic observation. RESULTS: Micro CT showed clearly 3-dimensional trabecular bone structure. New bone formation and bone marrow structure were observed in the observed area. Osteoblastic cells existed along the new bone, and osteopontin was localized in the bone matrix weakly. In the connective tissue around the new bone, many CD34-positive blood vessel cells were present. Some tartrate-resistant acid phosphatase (TRAP)-positive osteoclastic cells were observed around bone at this stage. CONCLUSION: The application of rhBMP-2 with ACS induced a new bone accompanied by blood vessels in atrophied alveolaris. This suggests that rhBMP-2 is capable of osteoinductivity in human jaw.

[Clinical evaluation of periodontal-orthodontic treatment in patients with aggressive periodontitis and malocclusion].

OBJECTIVE: To evaluate the clinical effect and safety of periodontal-orthodontic treatment in patients with aggressive periodontitis (AgP) and malocclusion. METHODS: A retrospective analysis was conducted in 25 AgP patients, who had received periodontal-orthodontic treatment in Peking University School and Hospital of Stomatology. Clinical indexes, including probing depth (PD), bleeding index (BI) and percentage of sites with bleeding on probing (BOP%) were evaluated at three time points: Baseline (T0); active periodontal treatment finished and before orthodontic treatment (T1); and after orthodontic treatment (T2). Also changes of ratio of the residual alveolar bone height (RBH) and the occurrence of root resorption were evaluated by periapical radiographs. RESULTS: (1) Compared with T0, all the clinical parameters including PD, BI, BOP% and percentage of sites with PD>3 mm were significantly improved (P<0.001). (2) Significant difference was observed in the average RBH between T0 (68.37%±15.60% and T2 (70.27%±14.23%). RBH in upper incisors [(58.79%±16.71% at T0, 65.54% (55.74%, 78.13%) at T2], upper canines [77.62% (66.06%, 87.17%) at T0, 79.57% (69.75%, 86.52%) at T2] and upper molars [74.30% (61.69%, 84.45%) at T0, 76.76% (68.12%, 85.09%) at T2] showed significant increase (P<0.05). (3) After orthodontic treatment, varying degrees of root resorption occurred in (23.94%±13.45%) of teeth per capita, among which the lower and upper incisors showed the highest incidence (68.48% and 65.31% in homogeneous teeth, respectively). CONCLUSION: After active periodontal treatment, orthodontic treatment in AgP patients had not aggravated inflammation and alveolar bone resorption; root resorption occurred in two-thirds of incisors approximately.

Comparison of Early Onset Nasoalveolar Molding With Patients Who Presented for Molding Up to 1 Year of Age.

PURPOSE: To compare the effectiveness of nasoalveolar molding (NAM) in infants with complete unilateral cleft lip and palate presenting before and after 6 months of age and justify its use in older infants presenting for treatment. MATERIALS AND METHODS: The university NAM protocol was followed for 150 patients who were included in the study. NAM was performed by 1 month of age (group I, n = 50), at 1 to 6 months of age (group II, n = 50), and at 6 months to 1 year of age (group III, n = 50). Seven linear anthropometric measurements were compared using dentofacial models. RESULTS: Statistical analysis before and after NAM showed that group I had 83, 176, 69, and 142% improvement in intersegment distance, nasal height, nasal dome height, and columella height, respectively. Group II had 53, 44, 30, and 67% improvement. Group III had 45, 38, 28, and 62% improvement. CONCLUSION: Patients in all 3 groups showed improvement with the NAM protocol. Although patients who presented for treatment before 1 month of age benefited the most, those who presented at 6 months to 1 year of age benefited as much from NAM as those who presented at 1 to 6 months, thus validating its use in these patients.

Controlled release of injectable liposomal in situ gel loaded with recombinant human bone morphogenetic protein-2 for the repair of alveolar bone clefts in rabbits.

BACKGROUND AND OBJECTIVE: The aim of the present study was to develop and examine a new non-invasive injectable graft for the repair of alveolar bone clefts using recombinant human bone morphogenetic protein-2 (rhBMP-2) encapsulated within injectable liposomal in situ gel (LIG). METHOD: Different liposomal formulations loaded with rhBMP-2 were prepared, and the effects of the preparation methods and lipid content on the efficiency of rhBMP-2 encapsulation within the liposomes were studied. For the preparation of in situ gel, deacetylated gellan gum (DGG) was used, and the in vitro gelation characteristics of the gel were evaluated. In vivo pharmacokinetics and histology were also assessed. Critical size alveolar defects were surgically created in the maxillae of 30 New Zealand rabbits and treated with different injectable formulae, including rhBMP-2 liposomes and in situ gel (rhBMP-2-LIG). RESULTS: The results indicated that the prepared rhBMP-2-LIG prolonged the release and residence time of BMP-2 within rabbits for more than 7 days. Histomorphometric assessment showed 67% trabecular bone filling of the defects treated using this novel formula. CONCLUSION: BMP-2-LIG is a promising delivery device for the repair of alveolar bone defects associated with cleft deformities.

Changes in the craniofacial complex and alveolar bone height of young adults: Applications to dental medicine.

The few studies on craniofacial complex changes in adults have reported contradictory findings. The aim of this study was to radiographically evaluate changes in the craniofacial complex and alveolar bone height of young adults over a 4-year period. This prospective study included 82 young adults (62 men; mean age, 19.0 ± 0.8 years; 20 women; mean age, 18.8 ± 0.9 years). Three radiographic examinations were performed longitudinally: the first (T0) was conducted at the start of the study, the second (T1) was conducted 2 years later, and the third (T2) was conducted at the end of the study period. As part of these examinations, lateral cephalograms, maxillary and mandibular anterior periapical radiographs, and bilateral posterior bitewing radiographs were obtained. During the 4-year follow-up period, all linear cephalometric measurements were significantly greater in men than in women. The amount of increase in the anterior facial height between T1 and T2 was lower in women than in men (P = 0.029). The rate of uprighting of the upper incisors was lower in men than in women over time (P = 0.020). The apex of the nose moved inferiorly between T0 and T2 (P = 0.006). The average overall change in the alveolar bone height was 0.27 mm and the yearly change was 0.07 mm over the 4-year period (P< 0.001). Significant changes in the skeletal, dental, and soft tissue, as well as, natural changes in alveolar bone, occur in young adults over time. Clin. Anat. 29:1011-1017, 2016. © 2016 Wiley Periodicals, Inc.

Palate and alveolar ridge development in predental infants: a longitudinal study.

AIM: To investigate the developmental process of palate morphology, including the alveolar ridge, in healthy infants for the predental period of 7 months from immediately after birth. METHODS: The subjects were 32 healthy infants. Four or more dental casts were taken of each subject from immediately after birth until 7 months, for a total of 144 dental casts. Twelve characteristics were then measured in order to morphologically study the subjects' palate development. Principal component analysis (PCA) was performed to investigate morphological changes in the palatal vault. RESULTS: The 12 characteristics were classified into either the alveolar ridge characteristics group, which determined the size of the alveolar ridge, or the palate characteristics group, which determined palate morphology, with each group showing different growth patterns. The characteristics of width and length increased with age in the alveolar ridge characteristics group; this correlation was maintained throughout the predental period. Meanwhile, in the palate characteristics group, the characteristics showed major developmental changes in the first 2 to 3 months after birth, but the changes were subsequently fewer from 3 to 7 months. The PCA of the palatal vault showed that the first principal component increased until 3 months but subsequently ceased to change. CONCLUSIONS: In predental infants, growth patterns of palate morphology differed according to their characteristics. There were major developmental changes in the palate during the first 3 months after birth. The study findings suggest that palate growth in the first half of the predental period may affect subsequent palate growth.

Effect of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats.

BACKGROUD: Normal occlusion is very important for physiological structure of mandible. However, the details of influences of occlusal hypofunction and its recovery on the three-dimensional architecture of mandibular alveolar bone in growing rats are still lacking. MATERIALS AND METHODS: Forty-eight growing male Sprague-Dawley rats were randomly divided into normal (n = 24), hypofunctional (n = 12), and recovery (n = 12) groups. The hypofunction group was developed by inserting a bite-raising appliance between the maxillary and mandibular incisors of the rats. Two weeks after insertion, the appliance was removed to result in the recovery group; the experiment continued for two additional weeks. The experimental animals and control animals were killed weekly. In addition to measuring the body weight and masseter muscle weight of the rats, the histomorphology and microstructure of the mandibular alveolar bone were scanned using microcomputed tomography. RESULTS: A lighter masseter muscle and a higher and narrower alveolar process were observed in the hypofunction group compared with the control animals (P < 0.05). Mandibular remodeling also occurred in the hypofunctional group, as demonstrated by a smaller trabecular cross-sectional area, looser trabecular bone, decreased bone volume fraction, trabecular thickness, trabecular number, and increased bone surface density and trabecular separation, especially at week 2 (P < 0.05). After removing the anterior bite-opening appliance, the altered masseter muscle weight and architecture of the mandibular alveolar bone were gradually reversed and reached normal levels at the end of the experiment (P > 0.05). CONCLUSIONS: A loss of occlusal stimuli can lead into mandibular alveolar bone remodeling, and the recovery of occlusion can restore the altered mandibular architecture in growing rats.

Long-term follow up of 103 ankylosed permanent incisors surgically treated with decoronation--a retrospective cohort study.

BACKGROUND/AIM: Decoronation is a technique developed in 1984 to remove ankylosed teeth and increase marginal bone levels in young, growing individuals. This retrospective cohort study evaluates marginal bone development after decoronation in relation to gender and age at treatment. MATERIALS AND METHODS: The study evaluated all 95 patients with 103 ankylosed permanent incisors treated with decoronation at the Eastmaninstitutet Department of Pediatric Dentistry during 1978-1999. Mean age of the patients was 10.7 years (6.8-17.8) at the time of trauma and 14.9 years (9.3-22.0) at decoronation. The mean follow-up period was 4.6 years (1.0-19.3 years). The study evaluated development of the marginal alveolar bone level with a three-point scoring system: 1 = Unchanged or reduced alveolar bone level, 2 = A moderate increase in alveolar bone level, and 3 = A considerable increase in alveolar bone level. The final group for statistical evaluation comprised 75 patients: 56 boys and 19 girls who had only one tooth decoronated. Kappa statistics showed almost complete agreement between the two observers (κ = 0.90). RESULTS: Bone level changes were significantly correlated (P < 0.05) to gender and age at treatment. In decoronations performed after the age of 16, bone levels were unchanged or reduced, while decoronations performed at a mean age of 14.6 years in boys and 13 years in girls yielded a considerable increase in bone levels. CONCLUSION: This study indicates that age at decoronation is an important factor for favorable development of the alveolar ridge and that decoronation should be performed earlier in girls.

Evaluation of root and alveolar bone development of unilateral osseous impacted immature maxillary central incisors after the closed-eruption technique.

INTRODUCTION: In this study, we evaluated root and alveolar bone development in unilateral osseous impacted immature maxillary central incisors by cone-beam computed tomography before and after closed-eruption treatment, in comparison with naturally erupted contralateral immature maxillary central incisors. METHODS AND RESULTS: The study included 30 patients, 20 boys and 10 girls, with a mean age of 8.44 ± 1.20 years (range, 6.5-11.2 years). After treatment, the root lengths of both the impacted maxillary central incisors (10.66 ± 2.10 mm) and the contralateral maxillary central incisors (11.04 ± 1.76 mm) were significantly greater than their pretreatment values (6.67 ± 1.94 and 9.02 ± 2.13 mm, respectively). The root canal widths of the incisors decreased significantly after treatment. From the posttreatment cone-beam computed tomography images, the ratio of exposed root length to total root length and the thickness of the alveolar bone at 1 mm under the alveolar crest and at the apex were calculated to evaluate alveolar bone development. Impacted immature maxillary central incisors differed significantly from contralateral immature maxillary central incisors in labial exposed root length, labial ratio to total root length, and lingual alveolar crest. Clinical crown height was higher (statistically but not clinically) for the impacted incisors (9.87 mm) than for the contralateral incisors (9.37 mm). CONCLUSIONS: Impacted immature incisors grew to the same stage as did erupted contralateral incisors after closed-eruption treatment. Both incisor types had some alveolar bone loss, and thin alveolar bone surrounded the roots.

Cervical vertebrae maturation, dentoalveolar, head postural and respiratory parameters in predicting the stable outcome of face-mask treatment.

BACKGROUND/OBJECTIVES: To select predictors related to cervical vertebrae maturation (CVM), dentoalveolar adaptation, head posture, and respiration on outcome of face-mask treatment. MATERIALS/METHODS: Forty-six patients (24 boys and 22 girls) with skeletal Class III pattern whose CVM stages ranged from I to IV at pretreatment were selected. The observation period was 2.87 ± 1.77 years from the end of treatment. Negative overjet and overbite was regarded as unstable. CVM, 10 skeletal variables, 6 dental adaptation variables, 4 alveolar housing variables, an airway variable, and 2 head posture variables were chosen for discriminant analysis of initial characteristics between stable and unstable groups. RESULTS: Measurements exhibiting strong correlations were distance from lower incisor to Nasion, B point (NB), Frankfort horizontal plane to Mandibular incisor Angle (FMIA), incisor overbite, body to anterior cranial base. LIMITATIONS: We missed muscle-related variables, which cannot be identified in a cephalogram. CONCLUSIONS/IMPLICATIONS: Presence of non-skeletal cephalometric factors more closely associated with stability of face-mask treatment rather than skeletal cephalometric factors at the initial stage are confirmed.

The nasomaxillary complex and the cranial base in artificial cranial deformation: relationships from a geometric morphometric study.

INTRODUCTION: It is widely accepted that there is a relationship between the cranial base and the development of the nasomaxillary complex (NMC). The objective of the present study was to investigate the morphological relationship between these two anatomical units in skulls that have intentionally been subjected to one of two types of artificial deformity of the cranial vault [artificially deformed skulls (ADS)]. MATERIAL AND METHODS: A geometric morphometry study was performed on lateral cephalometric X-rays of three groups of crania: 32 with anteroposterior (AP) deformity, 17 with circumferential (C) deformity, and 39 with no apparent deformity. RESULTS: The cranial base of the ADS showed marked deformity that produced a restriction of AP growth of the NMC, alterations of the roof of the orbit as a consequence of the rotation of anterior cranial fossa, and nasal protrusion. Pronounced morphological differences were found between the three groups: increased vertical development of the maxilla occurred in both ADS groups due to growth of the alveolar process, and rotation of the maxilla and displacement of the orbital rim was observed in the C group. This confirms that the posterior facial plane is regarded as an axial structure that serves as an interface between the middle cranial base and the NMC (Enlow, D.H. and Hans, M.G. (1996) Essential of Facial Growth. WB Saunders Co., Philadelphia, PA). LIMITATIONS: It is important to take into account that these results have been obtained from an archaeological sample, with all the limitations that this implies such as being a small sample and with no absolute certainty regarding the use of the same type of deforming device within each group. Furthermore, this is a lateral two-dimensional study in which transverse development has not been analysed. CONCLUSIONS: Artificial modification of the shape of the vault has repercussions on the NMC that support the theory of an all-inclusive integration of the different cranial units in normal as well as in restricted development.

Alveolar bone retention following treatment of dilacerated labial inversely impacted maxillary central incisors-a retrospective study.

The root of late-dental-age labial inversely impacted maxillary central incisors (LIIMCIs) typically develops to severe dilacerated morphology. Therefore, reliable posttreatment periodontal estimates of orthodontic treatment prognosis would be critical to the treatment value of impacted incisors. This study aims to analyze further changes in dimensions of the alveolar bone following the closed-eruption treatment of late-dental-age dilacerated LIIMCIs. Cone beam computed tomography (CBCT) scanning data of 16 patients with unilateral dilacerated late-dental-age LIIMCIs were collected, including the pretreatment (T1) and at the 2.23 ± 0.78 years follow-up stage (T2) respectively. Patients underwent closed-eruption treatments to bring the impacted incisor into the dental arch. Dolphin imaging software was used to measure alveolar bone height labially, palatally, and proximally to the site at T1 and T2, as well as alveolar bone thicknesses at 0, 2, 4, 6 and 8 mm below the initial measurement plane (IMP). The alveolar bone heights on the impacted and contralateral sides increased from T1 to T2 (p < 0.05). Alveolar bone growth on both sides had no significant difference. In T2, the mean values of labial and distal alveolar heights on the contralateral sides were greater than on the impacted sides (p < 0.05). The mean values of total alveolar bone thicknesses on the impacted sides in T1 were significantly smaller than those on the contralateral sides in IMP-0, 2, 4, 6, 8 (p < 0.05). The total thicknesses on the impacted sides in T2 increased and were significantly greater than on the contralateral sides (p < 0.05), except for the thickness in IMP-0. The closed-eruption treatment of dilacerated late-dental-age LIIMCIs results in no significant changes to alveolar bone height, except on the labial and distal sides, with increased alveolar bone thickness, suggesting that this approach may be viable first choice therapy for non-extraction orthodontic cases.