To investigate the expression and distribution of sclerostin in the alveolar bone of rat in the absence of estrogen, and to provide evidence for the analysis of the histological correlation between sclerostin and alveolar bone remodeling in rats.

The experimental subjects of this study were 32 8-week-old female Wistar rats. Among them, 16 rats were ovariectomized (OVX), and 16 rats were subjected to a sham operation (Sham). These rats were sacrificed 1, 2, 3, and 4 weeks after the operation, and the mandibles were removed and embedded. The mesial and distal sections of the rat’s mandibular first molars were selected and stained with anti-tartrate phosphatase (TRAP), sclerostin immunostaining, multiple immunostainings, RANKL and TRAP double staining, and silver-plated multiple staining.

As the postoperative time in rats increased, the TRAP-positive osteoclasts counts in the OVX group in the interalveolar septum of mandibular first molar increased significantly, and statistical difference was noted between the groups (P < 0.05). The OVX 2w, 3w, and 4w groups exhibited more TRAP-positive osteoclasts compared with the Sham group at the corresponding time point, and the results were statistically different (P < 0.05). Sclerostin immunostaining revealed that the proportion of positive bone cells in the mesial side of the periodontal ligament area of mandibular first molar in the OVX group gradually decreased. Statistical differences were noted between the OVX 3w group and the OVX 4w group as well as the OVX 1w group and, the OVX 2w group (P < 0.05). In the comparison between the area near the periodontal ligament and the central area of the alveolar bone septum of the mandibular first molar in the same group, the positive expression ratio of sclerostin in the OVX 3w and OVX 4w groups in the area near the periodontal ligament was reduced compared with that in the central area of the alveolar bone septum. The results were statistically significant (P < 0.05). A larger number of osteoblasts was noted around the osteoclasts in the OVX 4w group compared with the Sham 4w group based on ALP/ TRAP /sclerostin multiple staining, whereas less sclerostin-positive osteoblasts were noted in the OVX 4w group. Sclerostin/TRAP/silver plating staining showed that the bone tubules around the sclerostin positive bone cells mostly exhibited a parallel and neat arrangement, and the bone tubules around sclerostin negative bone cells were more irregular and disorderly arranged in the OVX 4w group.

Sclerostin protein is involved in alveolar bone remodeling in estrogen-deficient rats.

To evaluate the clinical restorative effect of anterior thin porcelain laminate veneers.

Thin Porcelain laminate veneers were applied to 112 teeth of 64 patients for anterior aesthetic restoration. The follow-up time was 24 months. The veneers were examined with a modified Ryge criteria.

The fracture of the incisal edge on 2 veneers was noticed after 12 months. After 24 months, the partial fracture of the distal incisal corner on 1 veneer was noticed; a gap was detected on the margin of another veneer and discoloration was observed on 5 ones. None of cases showed dentin hypersensitivity or gingivitis.

A satisfying effect could be gotten by using thin porcelain laminate veneer in the anterior teeth with the advantages of less tooth preparation, high repair strength, and not easy to fall off break.

Exploring the position and bone wall thickness characteristics of the maxillary central incisors in Southern Chinese adults to provide a clinical reference for the design of immediate maxillary central incisor implantation surgery.

The hospital ethics committee approved the study, and the patients provided informed consent. CBCT images of 990 adult patients (aged 20-79 years) from the Stomatology Hospital (January 2018 to December 2021) were categorized based on the dental arch form and age-sex groups. Sagittal CBCT images of the maxillary central incisors were used to measure the labial and palatal bone thickness wall at 4 mm the CEJ to apical, the middle of the root, and the angle between the tooth long axis and the long axis of the alveolar process, to compare the thickness of the labial and palatal bone walls in samples of male and female patients, and to explore the relationship between the angle between the tooth long axis and the alveolar process long axis in samples of male and female patients in different age groups (20-39 years; 40-59 years; 60-79 years).

Significant differences were found in the labiopalatine side of the alveolar bone of the maxillary incisor root position. A total of 95.8% (948/990) of the maxillary incisors were positioned more buccally, 4.1% (41/990) were positioned more midway, and 0.1% (1/990) were positioned more palatally. The thicknesses of the bone wall at the CEJ of 4 mm below the palatal side, the middle of the root, and at the apex were greater (1.82 ± 0.56 mm, 3.20 ± 1.10 mm, and 7.70 ± 2.00 mm, respectively) than those at the labial side (1.21 ± 0.32 mm, 0.89 ± 0.35 mm, and 1.86 ± 0.82 mm, respectively), with statistical significance (P<0.05). Male bone wall thickness was generally greater than female bone wall thickness (P<0.05). The angle between the long axis of male teeth and the alveolar bone was 14.77° ± 5.66°, while that of female teeth was 12.80° ± 5.70°, with a statistically significant difference (P<0.05). The angle between the long axis of teeth and the alveolar bone in the 40-59-year-old group and the 60-79-year-old group was greater than that in the 20-39-year-old group, and the difference was statistically significant (P<0.05).

A total of 95.8% of adults in South China have maxillary central incisors with root deviation toward the labial bone cortex. The thickness of the labial bone wall is much thinner than that of the labial bone wall, which is the middle of the thickness of the root. In Southern Chinese adults, the angle between the upper central incisor and the long axis of the alveolar bone in males is greater than that in females, and the degree of the angle increases with age. It is recommended to pay attention to the thickness of the bone wall around the root and the angle between the teeth before immediate implantation surgery to choose a reasonable implantation plan.

To analyze the spatial relationship between the roots of maxillary anterior premolars and the maxillary sinus, thus providing an anatomical basis for timing, planning, surgical approaches, and implant selection at this site.

Cone beam CT (CBCT) images were collected from 264 patients (aged 20-65 years) who visited the Ruihua Dental Clinic between January 2017 and March 2023. The minimum distance from the apex of the maxillary anterior premolar roots to the lower wall of the maxillary sinus was measured on the coronal plane. The classification of the vertical relationship between the tooth root and the lower wall of the maxillary sinus was performed, and comparisons were made bilaterally, between genders, and among different age groups.

The minimum distance (Q₅₀) from the apex of the first maxillary premolar root to the lower wall of the maxillary sinus was 7.34 mm for the single-root type, 7.80 mm for the buccal root of the double-root type, and 7.36 mm for the palatal root. For the second maxillary premolar, the median distance was 2.56 mm for the single root type, 1.73 mm for the buccal root type, and 1.23 mm for the palatal root type. There was a significant difference in the shortest distance from the apex of the right second maxillary premolar single root to the lower wall of the maxillary sinus among the different age groups (P＜0.05), with the 20-29-year-old group having the smallest median distance (1.52 mm) and the ≥ 40-year-old group having the largest (4.44 mm). There was no significant difference in the effect of sex or laterality on distance (P＞0.05). The most common vertical relationship between the apex of the maxillary anterior premolar roots and the lower wall of the maxillary sinus was non-contact. There was no significant difference in the vertical relationship classification between the single-root and double-root types (P＞0.05).

Most maxillary first premolar roots can provide sufficient bone height, which makes it easy to achieve immediate implantation. The maxillary second premolar root frequently involves insufficient bone, which is necessary to make full use of the bone wall of the extraction socket or the sinus floor cortical bone to achieve initial stability. The vertical relationship between the premolar root and maxillary sinus was influenced by age and dental position. Younger age groups often exhibit inadequate bone height, and the indication for immediate implantation should be carefully considered. The number of roots does not significantly affect the relationship between the sinus and root; however, double-rooted premolars offer more support for immediate implantation and socket healing due to the small root diameter and bony separation between the roots.