The Chinese journal of dental research : the official journal of the Scientific Section of the Chinese Stomatological Association (CSA)最新文献

Objective: To compare accuracy, duration of drilling and accumulation of bone chips between low-speed drilling and conventional drilling in freehand implant placement surgery.

Methods: The implant surgery procedures were performed using identical drill bits on pig ribs in the low-speed drilling group and the conventional drilling group. CBCT images of the preoperative implant design and postoperative implant positions were compared by using the space vector formula to calculate the angular deviation of the implants between the two groups, as well as the horizontal and vertical deviations of the implant necks and roots. The duration of the procedure was recorded, and the bone chips were collected and compared using a screening method and scanning electron microscopy.

Results: There were no significant differences in any of the four primary outcome variables relating to accuracy between the low-speed and conventional drilling methods. However, the results revealed that the length of the procedure differed significantly between the two groups and more large bone fragments could be collected when performing low-speed drilling.

Conclusion: Low-speed drilling does not affect the accuracy of implant nest preparation, but it can harvest large bone chips which may have better osteogenic activity. Low-speed drilling could be an alternative to conventional drilling.

Objective: To establish precise positional references for orthognathic surgery by examining the relative positioning of the infraorbital foramen (IOF) in relation to the anterior nasal spine (ANS) and the mental foramen (MF) in relation to the pogonion (Pog).

Methods: A cohort of 115 patients with CBCT images was randomly selected for analysis. Distances and positional relationships between the IOF and ANS, as well as the MF and Pog, were measured using 3D reconstruction images.

Results: On average, the ANS was situated 21.40 mm below the IOF, with a horizontal distance of 26.42 mm. The horizontal and vertical distances between the MF and Pog were 23.57 and 9.71 mm, respectively. Scatter plots centred on the ANS indicated that 83% (191/230) of the IOF were distributed in a 30- to 45-degree fan shape, the radius of which ranged from 30 to 40 mm. Similarly, 98% (226/230) of the MF occupied a 45-degree fan shape within a 20 to 30 mm radius in the bilateral superior quadrant centred on the Pog.

Conclusion: During maxillary osteotomy, there is a potential risk of damaging the infraorbital neurovascular bundle located 21.40 mm above the ANS. To mitigate the risk of IOF injury, caution is advised, particularly when retracting the flap below a 30-degree fan shape within a 30 to 40 mm radius centred on the ANS and a 45-degree fan shape within a 20 to 30 mm radius centred on the Pog. Special attention is warranted during flap elevation in this specified area.

Objective: To investigate the prevalence and characteristics of taurodontism in patients with cleft lip and palate (CLP) and clarify the relationship between CLP and the frequency and severity of taurodontism.

Methods: CBCT scans of 30 patients with bilateral CLP (BCLP), 70 with unilateral CLP (UCLP) and 70 healthy individuals were taken for investigation. In each group, the first and second molars were assessed for the presence of taurodontism. In taurodontic teeth, the severity of taurodontism was measured and classified based on the taurodontic index (TI). The frequency and severity of taurodontism were compared between the three groups.

Results: Taurodontism was significantly higher in patients with CLP (P < 0.001), and its prevalence was significantly higher in patients with BCLP than those with UCLP (P = 0.003) and the control group (P < 0.001). There was no difference among the three groups regarding the severity of taurodontism. Additionally, the frequency of taurodontism in the second molars was significantly higher than that in the first molars in the control group (P = 0.019).

Conclusion: Based on this investigation, clinicians should be aware of the possible complications that may occur when performing dental procedures on patients with BCLP and UCLP due to the higher incidence of taurodontism in these patients.

Oral diseases not only greatly impact patients' daily lives, but also pose a severe threat to their overall health. Due to the constant exposure of saliva to oral diseases, the former plays a vital role in their diagnosis and monitoring. Exosomes, nanosized bilayer lipid encapsulated nanovesicles, are widely present in saliva and can be released by any type of cell. Exosomes inherit features from their mother cells in both physiological and pathological conditions. The molecular characteristics and expression levels of exosomes depend on their cellular origin, and they can directly reflect the physiological state of the body and cells. This makes salivary exosomes a promising source for early detection and monitoring of oral diseases. As a result, researchers have been exploring the potential use of exosomes as biomarkers for diagnosing and predicting various oral diseases. This review provides an overview of the composition, separation and function of salivary exosomes. It also discusses their potential as diagnostic and prognostic markers for several oral diseases, including periodontitis, primary Sjögren's syndrome, oral mucosal diseases, hand-foot-mouth disease and oral squamous cell carcinoma. By studying salivary exosomes, researchers hope to improve the early detection and monitoring of oral diseases, leading to better outcomes for patients.

Impaction of mandibular second molars should be resolved as soon as possible once diagnosed, since it may lead to many functional, periodontal, hygienic and endodontic problems. Treatment options for impacted second molars include orthodontic-assisted eruption following surgical exposure, surgical uprighting and, in some cases, surgical extraction with possible subsequent implant placement if the tooth is deemed non-restorable or the patient prefers an implant restoration. This case report describes the orthodontic treatment of a 21-year-old woman with maxillomandibular protrusion and impacted bilateral mandibular second molars. The Physiologic Anchorage Spee-wire System (PASS) was adopted due to its innovative strategy of physiological anchorage control and unique design involving the multilevel low-friction (MLF) bracket and cross buccal tube (XBT). After 22 months of treatment, a well-aligned dentition, a normal functional occlusion and a harmonious facial profile were obtained, and impaction of the bilateral mandibular second molars was finally resolved. This case report demonstrates a simple and efficient solution to dental impaction. The PASS technique is superior to other preadjusted straight wire appliances in the treatment of maxillomandibular protrusion cases without auxiliary anchorage devices, and the mandibular buccal tube involved in the PASS technique can assist in uprighting the impacted mandibular second molars with NiTi round wire and minimising oral discomfort for the patient.

Objective: To assess the role of microtubule acetylation in the transportation of amorphous calcium phosphate (ACP)-containing vesicles that mediate the osteogenic differentiation process of rat bone mesenchymal stem cells (BMSCs).

Methods: Rat BMSCs were cultured and transfected with sirtuin 2 (SIRT2) overexpression plasmids for an in vitro model. The microtubule acetylation-related protein levels were detected by western blots. The microtubule acetylation and the secretion rate of extracellular ACPcontaining vesicles were observed with immunofluorescence and live cell fluorescence imaging. The secretion of ACP was observed by transmission electron microscopy. The mineralised nodule formation was stained with Alizarin Red S staining and observed by microscopy.

Results: Microtubule acetylation was increased during osteogenic differentiation of BMSCs, and microtubule transport efficiency was enhanced. Mechanically, microtubule acetylation is the key reason for the increased transportation rate of ACP-containing vesicles and enhanced osteogenic differentiation, as both were blocked after SIRT2-mediated microtubule acetylation inhibition.

Conclusion: Microtubule acetylation mainly promotes the transportation and secretion of ACP vesicles, and ultimately promotes the osteogenic differentiation process.

Tooth eruption is the process whereby the developing tooth moves to its functional position in the occlusal plane and it occurs concomitantly with formation of the tooth root, which is a critical component of the tooth anchored to surrounding alveolar bone through the periodontal ligament. Post-eruptive tooth movement ensues that once occlusion is achieved, the teeth maintain their alignment within the alveolar bone to facilitate proper bite function through periodontium remodelling. Tooth overeruption presents a clinically significant issue, yet the precise mechanisms by which alterations in occlusal forces are translated into periodontal remodelling remain largely unexplored. In this review, the present authors aim to outline the latest progress on the potential mechanisms governing tooth root formation and homeostasis during tooth eruptive and post-eruptive movement. Based on recent findings using various mouse models, we provide an overview of the collaborative intercellular interaction during root formation, including Hertwig's epithelial root sheath, dental papilla and dental follicle. Moreover, we summarise the potential mechanism underlying post-eruptive movement mainly in view of the responses of periodontal tissues to vertical mechanical stimuli. In sum, the precise regulatory mechanisms during tooth eruption throughout life will shed light on disease treatment of tooth eruption defects and overeruption.

Objective: To investigate the antioxidant enzyme status in biological samples of patients with oral squamous cell carcinoma (OSCC) and compare them with biological samples of healthy people through a systematic review and meta-analysis.

Methods: Antioxidant enzymes of catalase (CAT), sodium dismutase (SOD) and glutathione peroxide (GPx) were included in the analysis. A literature search was conducted of the PubMed, Science Direct, Scopus, Web of Science and Wiley Online Library databases for studies published between January 1999 and December 2022. A total of 831 articles were selected, of which 131 were found to be relevant. Finally, the full texts of 12 studies were screened and included. Studies that evaluated other antioxidant enzymes were excluded. Standardised mean difference (SMD) was derived to conduct a meta-analysis using comprehensive meta-analysis v3 (Biostat, Englewood, NJ, USA). A random effects model with 95% confidence interval (CI) was used to estimate the effect size. P < 0.05 was considered significant.

Results: CAT levels were measured in eight studies (n = 567) and the mean values for the OSCC and control groups were 4.81 ± 2.57 and 10.02 ± 1.81, respectively (SMD 3.18, 95% CI 1.01 to 1.42; P = 0.001). SOD level was evaluated in 11 studies (n = 762) and the values for the OSCC and control groups were 3.78 ± 1.45 and 7.34 ± 1.79, respectively (SMD 3.66, 95% CI 1.51 to 1.94; P = 0.001). GPx level was evaluated in 10 studies (n = 697) and the values for the OSCC and control groups were 13.33 ± 1.42 and 16.54 ± 2.9, respectively (SMD 1.91, 95% CI 1.34 to 1.77; P = 0.001). The heterogeneity between the studies was severe (I2 ≥ 90%). The risk of bias between studies was low to moderate.

Conclusion: Analysis revealed that the levels of antioxidant enzymes decreased in biological samples of patients with OSSC as compared to healthy controls. Understanding the pathological progress of OSCC by analysing the level of antioxidant enzymes is beneficial in formulating a personalised, targeted pro-oxidant therapy for cancer treatment.

Objective: To investigate the biological regulatory function of Gremlin1 (GREM1) and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta (YWHAH) in dental pulp stem cells (DPSCs), and determine the underlying molecular mechanism involved.

Methods: Alkaline phosphatase (ALP) activity, alizarin red staining, scratch migration assays and in vitro and in vivo osteo-/dentinogenic marker detection of bone-like tissue generation in nude mice were used to assess osteo-/dentinogenic differentiation. Coimmunoprecipitation and polypeptide microarray assays were employed to detect the molecular mechanisms involved.

Results: The data revealed that knockdown of GREM1 promoted ALP activity, mineralisation in vitro and the expression of osteo-/dentinogenic differentiation markers and enhanced osteo-/ dentinogenesis of DPSCs in vivo. GREM1 bound to YWHAH in DPSCs, and the binding site was also identified. Knockdown of YWHAH suppressed the osteo-/dentinogenesis of DPSCs in vitro, and overexpression of YWHAH promoted the osteo-/dentinogenesis of DPSCs in vitro and in vivo.

Conclusion: Taken together, the findings highlight the critical roles of GREM1-YWHAH in the osteo-/dentinogenesis of DPSCs.

Objective: To reveal the role and mechanism of cannabinoid receptor 1 (CB1) and mitochondria in promoting osteogenic differentiation of periodontal ligament stem cells (PDLSCs) in the inflammatory microenvironment.

Methods: Bidirectional mitochondrial transfer was performed in bone mesenchymal stem cells (BMSCs) and PDLSCs. Laser confocal microscopy and quantitative flow cytometry were used to observe the mitochondrial transfer and quantitative mitochondrial transfer efficiency. Realtime reverse transcription polymerase chain reaction (RT-PCR) was employed to detect gene expression. Alkaline phosphatase (ALP) activity, alizarin red staining (ARS) and quantitative calcium ion analysis were used to evaluate the degree of osteogenic differentiation of PDLSCs.

Results: Bidirectional mitochondrial transfer was observed between BMSCs and PDLSCs. The indirect co-culture system could simulate intercellular mitochondrial transfer. Compared with the conditioned medium (CM) for BMSCs, that for HA-CB1 BMSCs could significantly enhance the mineralisation ability of PDLSCs. The mineralisation ability of PDLSCs could not be enhanced after removing the mitochondria in CM for HA-CB1 BMSCs. The expression level of HO-1, PGC-1α, NRF-1, ND1 and HK2 was significantly increased in HA-CB1 BMSCs.

Conclusion: CM for HA-CB1 BMSCs could significantly enhance the damaged osteogenic differentiation ability of PDLSCs in the inflammatory microenvironment, and the mitochondria of CM played an important role. CB1 was related to the activation of the HO-1/PGC-1α/NRF-1 mitochondrial biogenesis pathway, and significantly increased the mitochondrial content in BMSCs.