Labial Side Research Articles

Ancient Species of the Genus <i>Dvinosaurus</i> (Temnospondyli, Dvinosauria) from the Permian Sundyr Tetrapod Assemblage of Eastern Europe

From the Sundyr-1 reference locality of the Sundyr faunal assemblage of Eastern Europe (Upper Permian, Upper Severodvinian Substage, Suchonica vladimiri Assemblage Zone), the oldest species of the genus Dvinosaurus Amalitzky, 1921 Dvinosaurus gubini sp. nov. The diagnostic criterions for the new species are its smaller size compared to other dvinosaurs, the narrowest skull, short and wide zygomatic bone, parasphenoid body with a more wide base of the cultriform process and a well ossified basisphenoid, a strongly curved dentary with a well-defined symphyseal crest extending downward from the labial side of the symphysis and, in a several cases, with a single symphyseal canine, a large angle (135–152°) between the clavicular plate and the dorsal process of the clavicle, narrow areas of the interclavicle for insertion of the clavicles, narrow entepicondylus of the humerus. The size, narrowness of the skull, the presence of a single symphyseal canine, and hypocentrum structure bring together a new form closer to the basal Dvinosauria, in particular, with ancestral Trimerorhachidae.

Research progress on labial protuberances of anterior teeth in orthodontic treatment

During orthodontic treatment, irregular and varying sized nodular bony protrusions may sometimes appear on the labial side of the patient's anterior alveolar bone, which is closely related to the differential bone remodeling on the inner and outer surfaces of the alveolar bone. Labial protuberances not only affect the aesthetic results of orthodontic treatment, but also pose potential risks to periodontal health. Currently, it is believed that the influencing factors of the formation of the labial protuberances may be related to the patient's gender and age, tooth movement speed, and extent of anterior teeth retraction. Labial protuberances typically resolve spontaneously, however, if persistent, alveoloplasty may be necessary for treatment. This review provides a summary on the occurrence, influencing factors of formation, potential biological mechanisms, and corresponding treatment methods of labial protuberances during orthodontic treatment.

A small venomous reptile from the Late Triassic (Norian) of the southwestern United States.

Reptile feeding strategies encompass a wide variety of diets and accompanying diversity in methods for subduing prey. One such strategy, the use of venom for prey capture, is found in living reptile clades like helodermatid (beaded) lizards and some groups of snakes, and venom secreting glands are also present in some monitor lizards and iguanians. The fossil record of some of these groups shows strong evidence for venom use, and this feeding strategy also has been hypothesized for a variety of extinct reptiles (e.g., archosauromorphs, anguimorphs, and a sphenodontian). However, evidence of systems for venom delivery in extinct groups and its evolutionary origins has been scarce, especially when based on more than isolated teeth. Here, we describe a potentially venomous new reptile, Microzemiotes sonselaensis gen. et sp. nov., from a partial left dentary recovered from the Sonsela Member of the Chinle Formation (middle Norian, Upper Triassic) of northeastern Arizona, U.S.A. The three dentary teeth have apices that are distally reclined relative to their bases and the tip of the posteriormost tooth curves mesially. The teeth show subthecodont implantation and are interspaced by empty sockets that terminate above the Meckelian canal, which is dorsoventrally expanded posteriorly. Replacement tooth sockets are positioned distolingually to the active teeth as in varanid-like replacement. We identify this new specimen as a diapsid reptile based on its monocuspid teeth that lack carinae and serrations. A more exclusive phylogenetic position within Diapsida is not well supported and remains uncertain. Several features of this new taxon, such as the presence of an intramandibular septum, are shared with some anguimorph squamates; however, these likely evolved independently. The teeth of the new taxon are distinctively marked by external grooves that occur on the entire length of the crown on the labial and lingual sides, as seen in the teeth of living beaded lizards. If these grooves are functionally similar to those of beaded lizards, which use the grooves to deliver venom, this new taxon represents the oldest known reptile where venom-conducting teeth are preserved within a jaw. The teeth of the new species are anatomically distinct from and ~10x smaller than those of the only other known Late Triassic hypothesized venomous reptile, Uatchitodon, supporting venom use across multiple groups of different body size classes. This new species represents the third Late Triassic reptile species to possibly have used envenomation as a feeding (and/or defensive) strategy, adding to the small number of venomous reptiles known from the Mesozoic Era.

Analysis of factors affecting bone volume changes after immediate implantation in the maxillary central incisor.

This study aimed to evaluate the clinical outcomes of immediate implantation of single maxillary central incisor and explore factors affecting post-implant bone volume. Clinical data and imaging records from pre-surgery, the day of surgery, and 6 months post-surgery of 100 patients (100 implants) with non-salvageable maxillary central incisors who underwent immediate implantation were collected. Bone thickness at the cervical, middle, and apical regions of the implant's labial and palatal sides were measured immediately post-surgery and at 6 months, and bone volume changes were observed. A regression analysis model was used to assess predictive factors for labial and palatal bone plate thickness. At 6 months post-surgery, the labial bone thicknesses at the cervical, middle, and apical regions were 2.35, 2.29, and 3.28 mm, respectively, and those of the palatal side were 0.00, 2.40, and 6.05 mm, respectively. The cervical region had the highest alveolar crest collapse rates, with 32.87% on the labial side and 62.20% on the palatal side. The regression model indicated that factors influencing the thickness of bone at the cervical labial side of the implant included initial bone thickness, the implant center to adjacent tooth center angle, implant diameter, and the type of implant closure (P<0.05). The initial bone thickness on the palatal side was the sole predictor for bone thickness on the palatal side (P<0.05). Immediate implantation of single maxillary central incisors yields effective clinical results. The thickness of new bone around the implant is influenced by multiple factors. A comprehensive consideration of these factors in the planning of immediate implantation is necessary to achieve optimal therapeutic outcomes.

Comparative evaluation of alveolar bone remodeling and root length changes in fixed appliances versus clear aligners: A retrospective cohort study on skeletal Class III malocclusion treatment

The retrospective study examined changes in the root length and alveolar bone surrounding maxillary incisors in patients with skeletal Class III malocclusion treated by surgical orthodontic treatment with either fixed appliances (FAs) or clear aligners (CAs). A total of 60 subjects were divided based on appliance type used. Cone beam computed tomography scans were taken at three stages: before treatment, after presurgical orthodontic treatment, and post-treatment for both groups. Vertical alveolar bone level and horizontal alveolar bone thickness (ABT) were measured at four heights (3, 6, and 9 mm from the cementoenamel junction, and the root apex), along with root length, at these time points. Both groups showed a decrease in root length, with the CA group experiencing a significantly smaller reduction (0.4 ± 0.79 mm) compared with the FA group (0.64 ± 0.8 mm; P = 0.02). The FA group demonstrated more significant reduction in palatal ABT (P < 0.05) and greater root resorption, whereas the CA group exhibited considerable labial marginal bone resorption (P = 0.007) and a notable decrease in labiolingual inclination (P = 0.042). The findings suggest that FA and CA might lead to decreased ABT and significant root resorption, with FA therapy likely resulting in more pronounced effects. Both modalities led to notable vertical bone loss, particularly, on the labial side of the maxillary incisors in the CA group during postsurgical orthodontic treatment. Preventing iatrogenic deterioration of periodontal support surrounding the incisors is crucial during presurgical and postsurgical phases.

Simultaneous labial and lingual augmented corticotomy assisted presurgical orthodontics in class III patients: the morphological aspects of the mandibular anterior ridge with cone-beam computed tomography

ObjectivesThis study aims to investigate the changes in alveolar bone following the simultaneous performance of labial and lingual augmented corticotomy (LLAC) in patients with insufficient alveolar bone thickness on both the labial and lingual sides of the mandibular anterior teeth during presurgical orthodontic treatment.Materials and methodsThirth-five surgical patients with skeletal Class III malocclusion were included: 19 (LLAC group) accepted LLAC surgery during presurgical orthodontic treatment, and 16 (non-surgery group, NS) accepted traditional presurgical orthodontic treatment. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T0) and at the completion of presurgical orthodontic treatment (T1). The amount of vertical alveolar bone and contour area of the alveolar bone in the labial and lingual sides of mandibular incisors were measured.ResultsAfter presurgical orthodontic treatment, the contour area of the alveolar bone at each level on the lingual side and alveolar bone level on both sides decreased significantly in the NS group (P < 0.001). However, the labial and lingual bone contour area at each level and bone level increased significantly in the LLAC group (P < 0.001). The bone formation rate in the lingual apical region was the highest, significantly different from other sites (P < 0.001).ConclusionsDuring presurgical orthodontic treatment, LLAC can significantly increase the contour area of the labio-lingual alveolar bone in the mandibular anterior teeth to facilitate safe and effective orthodontic decompensation in skeletal Class III patients.Clinical relevance: This surgery has positive clinical significance in patients lacking bone thickness (< 0.5 mm) in the labial and lingual sides of the lower incisors.

Initial screening for dental abnormalities identified by labial and buccal photographs in dogs and cats.

To evaluate the dental abnormalities by visually assessing the labial and buccal photographs in dogs and cats and analyze their prevalence based on age and breed. 1,096 client-owned dogs and 775 client-owned cats. Data were collected from patients who visited 26 private veterinary clinics from January to December 2022. Each animal was evaluated through dental photographs taken from the labial and buccal sides. Correlations between the prevalence of the identified dental abnormalities and age, craniofacial type, and breed, were analyzed. Calculus, discoloration, epulis, fractured teeth, gingival recession, gingivitis, malocclusion, missing teeth, and persistent deciduous teeth could be identified by analyzing the dental photographs in both dogs and cats. Enamel defects in dogs and tooth resorption in cats could be identified. Brachycephalic dogs had a significantly higher prevalence of malocclusion (OR, 1.93; 95% CI, 1.36 to 2.75) and missing teeth (OR, 3.63; 95% CI, 2.71 to 4.91) compared to nonbrachycephalic dogs. Brachycephalic cats had a significantly higher prevalence of fractured teeth (OR, 1.95; 95% CI, 1.24 to 3.04) and a lower prevalence of gingival recession (OR, 0.30; 95% CI, 0.15 to 0.55) compared to nonbrachycephalic cats. Calculus, persistent deciduous teeth, and possibly gingivitis could be identified in dogs and cats by analyzing labial and buccal photographs. The assessment of some dental abnormalities such as fractured teeth, missing teeth, and tooth resorption can be limited without a complete dental examination under anesthesia. Although the assessment of dental conditions may be underestimated, the data on the prevalence of the dental abnormalities evaluated through the photographs could be utilized for screening dental diseases.

Impact of labially inclined implant axes on immediate implant placement and provisionalization in anterior maxilla: A prospective cohort study.

To investigate whether a labially inclined implant axis compromises the clinical outcomes of immediate implant placement and provisionalization (IIPP) in the anterior maxilla. Patients with unsalvageable central or lateral maxillary incisors were enrolled. IIPP with simultaneous connective tissue graft (CTG) was performed in all participants. In the control group, the alveolar ridge had a long axis aligned with the tooth, which ensured that the immediate implant was aimed at the incisor edge or the cingulum of future restoration. The test group had a large angle between the axes of the ridge and tooth. To avoid bone fenestration, the implants were placed labially inclined and emerged from the labial side of future restoration. Intra-oral scanning and cone-beam computed tomography were performed to record soft and hard tissue profiles at baseline and 1 year later. Soft tissue stability, bone remodeling, and pink esthetic score (PES) were evaluated and compared between two groups. Thirty-nine participants (19 tests and 20 controls) completed the study. At 1-year post-surgery, the mid-facial gingival margin migrations were 0.85 ± 0.37 mm (test) and 0.81 ± 0.33 mm (control), without significant differences. No differences were identified in buccal profile alteration, linear ridge reduction, buccal bone thickness, or PES scores. The test group demonstrated thinner buccal soft tissue at the crestal level than the control group. When large tooth-ridge angulation presented, labially inclined implant, avoiding buccal ridge fenestration in IIPP with CTG, did not compromise the clinical outcome in short term.

New Early Cretaceous zalambdalestid stem placental mammal from Mongolia and evolution of Zalambdalestidae

ABSTRACT Prozalambdalestes cratodus gen. et sp. nov. is based on a fragmentary dentary from the Lower Cretaceous (Aptian–Albian) Khovoor locality in Gobi Desert, Mongolia. This is the largest eutherian in the Khovoor mammal assemblage. It shows dental specializations of Zalambdalestidae such as procumbent, ever-growing gliriform first lower incisor with restricted enamel and reaching posteriorly p5, and mesiodistally compressed lower molar trigonids. The enamel is restricted to the ventrolabial and ventrolingual sides of the mesial half of the incisor and the enamel band is higher on the labial side. The new taxon retains five lower premolars, with p1 smaller than p2 and p3 smaller than adjacent premolars, and the Meckelian groove. It also differs from other zalambdalestids by position of mental foramina (under p3 and p5), p1–3 obliquely set in dentary, and lower molar talonids wider than trigonids. Phylogenetic analysis places Prozalambdalestes gen. nov. in a polytomy with Albian Zhangolestes, Turonian Kulbeckia, and the clade of Campanian zalambdalestids from Mongolia and Kazakhstan. CT data in Zalambdalestes and comparison with Prozalambdalestes gen. nov. show that the four lower premolars in Zalambdalestes are p2, p3 (variable present), p4, and p5. Consequently, the three lower premolars of Barunlestes and Zofialestes are p2, p4, and p5. The other diagnostic characters of Zalambdalestidae are reviewed.

Clinical outcomes of gingivoperiosteoplasty for unilateral cleft lip and palate performed in early childhood

Conventional gingivoperiosteoplasty (GPP) performed during infancy adversely affects maxillary development. However, the outcomes of this procedure in early childhood have rarely been reported. Therefore, we examined the postoperative outcomes of GPP conducted in patients aged 1.5 years with unilateral cleft lip and palate (UCLP).This study included 87 non-syndromic patients with complete UCLP who had undergone early two-stage palatoplasty during the 1999–2004 period. The protocol comprised soft palate plasty at 1 year of age and hard palate closure at 1.5 years of age. In the GPP group (n=34), we introduced the GPP procedure during hard palate closure; in the non-GPP group (n=53), the labial side of the alveolar cleft remained intact. We examined computed tomography images taken at 8 years of age to observe bone formation at the alveolar cleft site. We also conducted cephalometric analysis to examine maxillary development at 12 years of age.Bone bridges at the alveolar cleft site were observed in 92% and 5.6% of the GPP and non-GPP groups, respectively. Moreover, 59% of the GPP group did not require secondary alveolar bone grafting (sABG), whereas all the patients in the non-GPP group underwent sABG. No statistically significant differences were noted in the maxillary anteroposterior length (GPP: 45.5±3.7mm, non-GPP: 45.9±3.5mm, p=0.67) and sella–nasion–point A angle (GPP: 75.6±4.5°, non-GPP: 73.8±12.6°, p=0.49).This study’s findings suggest that GPP performed at 1.5 years of age minimises the necessity of sABG and does not exert a negative influence on maxillofacial development.

Effectiveness of bone plate reduction combined with resorbable plate fixation in the treatment of large mandibular cysts.

This study aims to observe the clinical effect of bone plate reduction in combination with a resorbable plate on large mandibular cysts. Between October 2017 and September 2022, patients with large mandibular cysts in the presence of labial and buccal cortical bone were involved in the study. Intraoral approach was performed for bone plate reduction. Cone beam computed tomography (CBCT) scan was reviewed at 3, 6, and 9 months postoperatively to observe postoperative complications. Osteogenic results were assessed at these times to determine the clinical outcomes of this procedure. Eleven cases with large mandibular cysts in the presence of cortical bone were evaluated. The average thickness of the cortical bone on the labial and buccal sides was measured to be about (1.98±0.37) mm before surgery, with a mean value of (0.73±0.17) mm at the thinnest part of the plate and up to 0.51 mm at the thinnest part of the plate. The cystic cavities were well revealed during the surgeries, which were completed successfully. Postoperatively, the wounds healed in one stage without infection. The percentages of cyst shrinkage were 20.01%, 41.76%, and 73.41% at 3, 6, and 9 months after surgery, respectively. Quantitative measurement of bone mineral density in the jaws by CBCT with MIMICS software. The bone mineral densities of the adult bone were 313.78, 555.85, and 657.45 HU at the 3, 6, and 9 month time intervals, respectively. No significant change in the patient's maxillofacial appearance were observed from the preoperative period as assessed by the patient's and observer's visual analog scale. Bone plate reduction is an effective treatment for large mandibular cysts of the oral and maxillofacial region with the presence of cortical bone.

Hemicentin-1 is an essential extracellular matrix component during tooth root formation by promoting mesenchymal cells differentiation.

Introduction: Root dentin formation is an important process in tooth development. We tried to identify potential genes that regulate root dentin formation which could be potentially used for the regeneration and repair of defective or damaged dental roots. Methods: Tissues harvested from the labial and lingual sides of mouse incisors were used for microarray analysis. Gene ontology (GO) analysis of differentially expressed genes indicated the critical role of extracellular matrix in the discrepancy of dentin formation between root and crown, for which hemicentin-1 (Hmcn1) was selected as the target gene. Single-cell RNA sequencing analysis the expression pattern of Hmcn1 at different developmental stages in mouse molars. The spatiotemporal expression of HMCN1 in mouse incisors and molars was detected by immunohistochemical staining. The functions of HMCN1 in human dental pulp cells, including proliferation, differentiation and migration, were examined in vitro by CCK8 assay, BrdU assay, wound-healing assay, ALP staining and alizarin red staining, respectively. Results: It was showed that HMCN1 expression was more pronounced in papilla-pulp on the root than crown side in mouse incisors and molars. In vitro experiments presented inhibited dentinogenesis and migration after HMCN1-knockdown in human dental pulp cells, while there was no significant difference in proliferation between the HMCN1-knockdown group and control group. Discussion: These results indicated that HMCN1 plays an important role in dentinogenesis and migration of pulp cells, contributing to root dentin formation.

Epidermal cell proliferation and differentiation in the beak of tadpoles of Rana dalmatina

AbstractEpidermal cell proliferation and differentiation during formation of the beak in tadpoles of Rana dalmatina. Acta Zoologica (Stockolm). The beak utilized in tadpoles of R. dalmatina for crushing vegetables is formed of cornified cell layers. A row of large wedge‐like cells forms a central pile that produces the sharp corneous lamina of the beak. The labial and oral surfaces of the beaks also accumulate corneous material during proliferation and differentiation of keratinocytes from the epidermis to form a sheath around the central corneous cells. Corneocytes are shed during the growth of tadpoles. Electron microscopy reveals that keratin and mucus granules are main components of these keratinocytes. Electron‐dense organelles of unknown composition and with inside lamellae are also present. Using immunohistochemistry after post‐injection of 5BrdU, a marker of cell proliferation, the main timing of formation of the beak has been determined. After 2–5 h from injection, labelled nuclei of keratinocytes are seen in the basal layer, and sparse suprabasal labelled nuclei are detected after 5 h. Labelled keratinocytes are seen in suprabasal layers at 2 days post‐injection. At 5 and 6 days labelled keratinocytes are present in central corneous cells and in the lateral shell of corneocytes forming the labial and oral beak sides. Shedding a complete stratum corneum likely takes more days, but this depends on feeding usage.

Dynamic monitoring and esthetic evaluation of dimensional changes in the peri-implant soft tissue contour after the immediate implant placement and provisionalization with the modified socket-shield technique in the esthetic zone

Objective: To accurately measure the dynamic changes of peri-implant soft tissue within one year after the immediate implant placement and provisionalization with the modified socket-shield technique (MSST) in the esthetic zone, and to provide a basis for evaluating the effect of the modified socket-shield technique on the maintenance of peri-implant soft tissue. Methods: A total of 22 patients (22 implants) were prospectively included 1 year after completion of immediate implant placement and provisionalization (IIPP) within MSST in the esthetic zone from January 2022 to January 2024 at the Department of Oral Implantology in the Stomatological Hospital of Chongqing Medical University. The intraoral optical models of patients were obtained by an intraoral scanner system preoperatively and at 3, 6, and 12 months postoperatively, respectively. The standard tessellation language files of intraoral optical models at multiple time points were imported to Geomagic Studio 2013 to be superimposed and aligned for analyzing the peri-implant soft tissue contour on the labial side of the implant site at multiple levels. The amount of gingival margin recession, gingival papilla change, and thickness change of the labial side of the soft tissues at each postoperative point in time were measured at each postoperative time point, as well as evaluating the esthetic effect by the pink esthetic score (PES). Results: The patients were (40±13) years old (21-75 years), including 9 males and 13 females. No adverse events occurred in all the implants during the 12-month follow-up period. The recession level of the gingival margin of the implant site (GL) was 0.08 (0.07) mm, the recession level of the mesial papilla (ML) was 0.19 (0.25) mm, and the recession level of the distal papilla (DL) was 0.19 (0.10) mm. The average collapse thickness of the soft tissue contour on the labial side of the implant (ΔD) was (0.39±0.09) mm, mainly occurring within 2 mm of the root of the gingival margin. The height of the alveolar bone was reduced by (0.17±0.08) mm. The thickness of the labial alveolar bone at 1, 3, and 5 mm root side of the implant shoulder was reduced by (0.13±0.08), (0.12±0.10) and 0.04 (0.17) mm, respectively. The postoperative pink esthetic score was 13.00 (2.25) points at 12 months, which suggested that all implant sites achieved ideal esthetic results. Conclusions: The labial soft tissue contour at implant sites shows minimal change following immediate implant placement and provisionalization using the modified socket-shield technique for 1 year in the esthetic zone.

Comprehensive three-dimensional cone beam computed tomography assessment unilateral alveolar cleft reconstruction using autologous iliac cancellous bone combined with deproteinized bovine bone: A clinical retrospective evaluation

Large-volume autologous iliac cancellous bone grafting for alveolar cleft may lead to undesirable bone resorption and susceptible donor-site morbidity, whereas the addition of deproteinized bovine bone (DBB) could optimize outcomes. This study aimed to evaluate the effectiveness of combining autologous iliac bone with DBB using three-dimensional cone beam computed tomography (3D-CBCT) for better analysis of bone generation than conventional evaluation methods. Thirty-six patients with unilateral alveolar cleft were assigned into two groups. Group A (n = 21) underwent autogenous cancellous bone graft harvested from the anterior iliac crests, while Group B (n = 15) received a composite of autogenous iliac cancellous bone and DBB. Patients in Group B displayed higher bone filling rates (P < 0.0001) and lower bone absorption rates (P < 0.001) than those in Group A at both 6 months and 1 year postoperatively. Additionally, there were directional differences in bone absorption within the bone grafts, with more absorption observed on the alveolar crest and palatal sides than that on the nasal and labial sides (P < 0.001). This study demonstrates that employing a combination of DBB and autologous bone in alveolar cleft repair achieves better outcomes of bone grafting.

Effects of Occlusal Contact on Maxillary Alveolar Bone Morphology in Patients with and without Anterior Open Bite: A Cross-Sectional Study.

Background/Objectives: Anterior open bite (AOB) is characterized by the absence of occlusal contact between the maxillary and mandibular anterior teeth, while the posterior teeth are in contact when occluded. Here, we aimed to clarify the difference in maxillary alveolar bone morphology in adult patients with and without AOB. Methods: This cross-sectional study was conducted on 50 adults aged 18-39 years: 25 patients without AOB (control group; 13 males and 12 females; age: mean ± standard deviation [SD], 22.2 ± 4.5 years) and 25 patients with AOB (9 males and 16 females; age: 24.2 ± 6.4 years). Using cone-beam computed tomography images, the height of the maxillary alveolar bone crest in the anterior and posterior teeth and thickness of the alveolar cortical bone on the labial and palatal sides were measured and compared between the two groups. An independent t-test and Pearson's correlation analysis were used to examine statistical significance (p < 0.05). Results: The AOB group showed a significantly longer (p = 0.016) posterior alveolar crest and thinner cortical bone on the buccal (p < 0.001) and lingual (p = 0.009) sides of the anterior region and the buccal (p = 0.006) sides of the posterior region than the control group did. Moreover, a significant negative correlation (p = 0.046; r = -0.403) was observed between bite force and cortical bone thickness on the buccal side of the posterior region in the AOB group. Conclusions: It is suggested that the absence of occlusal contact in the anterior area influences the alveolar bone morphology of the maxilla.

Three-dimensional analysis of the positional relationship between the dentition and basal bone region in patients with skeletal Class I and Class II malocclusion with mandibular retrusion.

This study aimed to determine the maxillary and mandibular basal bone regions and explore the three-dimensional positional relationship between the dentition and basal bone regions in patients with skeletal Class I and Class II malocclusions with mandibular retrusion. Eighty patients (40 each with Class I and Class II malocclusion) were enrolled. Maxillary and mandibular basal bone regions were determined using cone-beam computed tomography images. To measure the relationship between the dentition and basal bone region, the root position and root inclination were calculated using the coordinates of specific fixed points by a computer program written in Python. In the Class II group, the mandibular anterior teeth inclined more labially (P < 0.05), with their apices positioned closer to the external boundary. The apex of the maxillary anterior root was positioned closer to the external boundary in both groups. Considering the molar region, the maxillary first molars tended to be more lingually inclined in females (P = 0.037), whereas the mandibular first molars were significantly more labially inclined in the Class II group (P < 0.05). Mandibular anterior teeth in Class II malocclusion exhibit a compensatory labial inclination trend with the crown and apex relative to the basal bone region when mandibular retrusion occurs. Moreover, as the root apices of the maxillary anterior teeth are much closer to the labial side in Class I and Class II malocclusion, the range of movement at the root apex should be limited to avoid extensive labial movement.

Prenatal and postnatal development of New Zealand white rabbit (Oryctolagus cuniculus) teeth: histological and computed tomography aspects

The study reveals a lack of histomorphogenesis in New Zealand white rabbit teeth. The teeth development was examined through sequential histological segments in 24 rabbits from prenatal ages (E19, E21, E23, E25, and E28), neonates (E30), and postnatal age (1 week and 2 weeks); (three animal specimens at each age stage). Rabbit teeth first appeared at 19 days of prenatal life (E19) as an ectodermal epithelial thickening on each side of the mouth opening. At E21, the bud of upper incisor tooth appeared as an epithelial bud, which composed of many condensed epithelium cells, was simply identified from the larger with less condensed vestibular lamina, and was surrounded by mesenchymal connective tissue while the lower incisor took the cap stage. At (E23), tooth regular construction is formed from enamel, dentine, and pulp cavity. Peg incisor appearance (supplementary and assistant incisors) is visible at the lingual surface of the upper major incisor. Teeth prenatal development went through successive stages like initiation, bud, cap, late bell, maturation, and crown stages. The first initiation phase of tooth formation was seen as ectodermal epithelial cell collection at (E19). Bud stage saw on upper incisor tooth, while in cap structure in lower incisor teeth at (E19). A cap-formed tooth is composed of the enamel organ and fundamentally dense mesenchymal tissue. Enamel organs are segmented into three distinct layers: the external tooth enamel epithelial, the internal tooth enamel epithelial, and finally the stellate reticular layer. The cement layer covered teeth all around on enamel on both the labial and lingual sides while not contacting the dentine on the lateral side, forming enamel space. Teeth develop consistently all through life; they have expanded enamel thickness; they are diphyodont teeth; they have two continuous dentitions; they are deciduous and perpetual, with long crown teeth and an open root.

Early‐diverging Titanosauriform (Dinosauria, Sauropoda) Teeth from the Lower Cretaceous Yixian Formation of Southeastern Inner Mongolia, Northeast China

AbstractThree eusauropod teeth (SDUST‐V1064, PMOL‐AD00176, PMOL‐ADt0005) are reported from the Lower Cretaceous Yixian Formation of Ningcheng, southeastern Inner Mongolia, China. Two of them (SDUST‐V1064, PMOL‐AD00176) are assigned to early‐diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown, a slenderness index value &gt;2.0 and &lt;4.0, and D‐shaped cross section. Furthermore, SDUST‐V1064 and PMOL‐AD00176 are referred as an Euhelopus‐like titanosauriform on the basis of having a sub‐circular boss on the lingual surface and an asymmetrical crown‐root margin which slants apically, respectively. CT scan data of SDUST‐V1064 reveals new dental information of early‐diverging titanosauriforms, for example, the enamel on the labial side thicker than that on the lingual side, an enamel/dentine ratio of 0.26 and a boss present on the lingual side of the dentine of the crown.

Periodontal Abscess Occurrence Post Wire Splint Therapy on Mobile Teeth

Tooth mobility is one of the cases of periodontal disease caused by the destruction of the bone that supports the teeth. Stabilization of loose teeth using splinting wire can be one of the treatment options. The use of splinting wire may increase plaque accumulation and is sometimes difficult to clean. Plaque accumulation will cause bacterial invasion into the surrounding tissues of the periodontal pockets which will eventually develop into an inflammatory process. As time goes by, connective tissue destruction and pus formation will occur which eventually leads to a periodontal abscess. Periodontal abscess is a localized accumulation of pus in the gingival wall of a periodontal socket with periodontal tissue destruction. The purpose of this case report is to report the incidence of periodontal abscess after wire splinting application in a case of tooth unsteadiness. A 76-year-old female patient came to RSGM with complaints of feeling uncomfortable because some of her teeth were loose. The complaint has been felt approximately 1 year ago. The complaint was accompanied by pain when used to eat and toothbrushing. Objective examination showed reddish gingiva, rounded interdentals, soft consistency, and unstippling texture on the labial and lingual side of teeth 33, 32, 31, 41, 42 and 43 with BOP (+) at all points. The patient's Oral Hygiene Index (OHI) was 2.16 and PI was 18.67%. Probing depth average was 3 mm, recession was 3 mm, and tooth decay was grade 2. Supportive examination showed horizontal bone destruction in the anterior region of the mandible. The first visit was carried out wire splinting on the lingual part of the loose tooth, at the time of control there was a periodontal abscess on the labial side so the splinting was moved to the labial side. The increase in socket depth and the appearance of periodontal abscesses are caused by plaque accumulation which eventually makes bacteria invade the periodontal tissue. Periodontal therapy really needs to pay attention to the patient's OHI, therefore plaque control and removal of bacterial deposits must be carried out by scaling and root planning regularly and carrying out other periodontal therapies such as curettage if tissue destruction is severe enough