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 evaluate the diagnostic ability and clinical imaging features in maxillofacial soft tissue hypervascular tumours by 64-slice multidetector spiral computed tomography (64-MDCT) contrast-enhanced scanning.

Methods: In a retrospective study of 21 cases of hypervascular tumours, the degree of blood supply and indexes were assessed, and the pathological results were used as the diagnostic gold standard to evaluate the sensitivity and specificity of 64-MDCT plain scan and enhanced CT in the diagnosis of oral and maxillofacial soft tissue hypervascular tumours, using the receiver operating characteristic curve to analyse and evaluate the efficacy.

Results: Among 21 patients, the diagnostic accuracy of 64-MDCT contrast-enhanced scan was 90.48%, the area under the curve of venous phase CT value was 0.80, the sensitivity was 83.30% and the specificity was 72.73%.

Conclusion: 64-MDCT contrast-enhanced scan can be used to evaluate the blood supply of maxillofacial soft tissue hypervascular tumours before an operation. The CT value in the venous phase of tumours has the highest diagnostic effectiveness, which can reduce the risk of blood loss during surgery for maxillofacial hypervascular tumours. In addition, it has certain guiding significance for the formulation of clinical treatment plans.

Objective: To analyse the pan-genome of three black-pigmented periodontal pathogens: Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens.

Methods: Pan-genome analyses of 66, 33 and 5 publicly available whole-genome sequences of P. gingivalis, P. intermedia and P. nigrescens, respectively, were performed using Pan-genome Analysis Pipeline software (version 1.2.1; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, PR China). Phylogenetic trees were constructed based on the entire pan-genome and single nucleotide polymorphisms within the core genome. The distribution and abundance of virulence genes in the core and dispensable genomes were also compared in the three species.

Results: All three species possess an open pan-genome. The core genome of P. gingivalis, P. intermedia and P. nigrescens included 1001, 1514 and 1745 orthologous groups, respectively, which were mainly related to basic cellular functions such as metabolism. The dispensable genome of P. gingivalis, P. intermedia and P. nigrescens was composed of 2814, 2689 and 906 orthologous groups, respectively, and it was enriched in genes involved in pathogenicity or with unknown functions. Phylogenetic trees presented a clear separation of P. gingivalis, P. intermedia and P. nigrescens, verifying the reclassification of the black-pigmented species. Furthermore, the three species shared almost the same virulence factors involved in adhesion, proteolysis and evasion of host defences. Some of these virulence genes were conserved across species whereas others belonged to the dispensable genome, which might be acquired through horizontal gene transfer.

Conclusion: This study highlighted the usefulness of pan-genome analysis to infer evolutionary cues for black-pigmented species, indicating their homology and phylogenomic diversity.

Objective: To investigate the accuracy of dimensional evaluation and representation of artefacts generated by different gutta-percha (GP) cones with or without sealer with CBCT using a reproducible, standardised phantom root methodology.

Methods: The reproducible artificial phantom roots with six root canal sizes from #25 to #50 and 0.04 taper were aligned according to the jaw curvature in a stone model for dimensional measurements. Each root was scanned while empty and filled with four types of filling materials. The specimens were scanned using the CS 9300 3D (Carestream Dental, Rochester, NY, USA) (at two different resolutions), 3D Accuitomo (J Morita, Kyoto, Japan) and NewTom VGi (Verona, Italy) CBCT systems. The hyperdense and hypodense axial slice artefacts from root canal sizes #40, #45 and #50 were recorded.

Results: Dimensions were significantly smaller and more accurate with CS 9300/0.09 mm voxel size than with other protocols. The hypodense band was found mostly in the CS 9300 3D system with 0.18 mm voxel size, especially in the buccal-lingual (95%) and coronal (64%) sections. The 3D Accuitomo CBCT system showed the lowest presence of the hypodense band. Areas of both light and dark artefacts were significantly larger in the coronal third than in the apical and middle thirds.

Conclusion: Artefacts in the coronal locations and in buccal-lingual sections were more evident in the CS 9300 3D system with a 0.18-mm voxel size.

Objective: To analyse the effects of premolar extraction on the upper airway in adult and adolescent orthodontic patients using CBCT.

Methods: The Embase, Web of Science, Cochrane Library and Medline (via PubMed) databases were searched with no language restrictions. Longitudinal studies in which CBCT was applied to assess the effects of tooth extraction on the upper airway were included in the analysis. Two authors performed the study selection, methodological quality assessment, data extraction and data synthesis independently.

Results: A total of 12 studies were included, six of which were eligible for quantitative synthesis. In the adult group, the nasopharynx and oropharynx volume showed no significant change, and the minimum cross-sectional area of the upper airway demonstrated a non-significant decrease compared to the non-extraction group. In the adolescent group, the nasopharynx volume, oropharynx volume and minimum cross-sectional area of the upper airway increased in a non-significant manner.

Conclusion: The currently available evidence indicates that tooth extraction does not increase the risk of airway collapse in adult and adolescent patients. The present findings should be interpreted with caution and evaluated in further high-quality studies.

In recent years, as the number of adults seeking orthodontic treatment has increased, so too has the number of periodontal tissue problems, particularly regarding the impact on periodontal tissue of receiving orthodontic treatment. Orthodontic treatment improves the occlusion and appearance of teeth by moving the teeth appropriately. These movements have a significant impact on the interactions between the teeth and periodontal tissues. Orthodontic treatment can also recover tooth alignment for patients with tooth displacement caused by periodontitis; however, orthodontic treatment also often has adverse effects on periodontal soft tissue, such as gingivitis, gingival enlargement and gingival recession. The purpose of this review is to summarise the current evidence and solid knowledge of periodontal soft tissue problems in orthodontic treatment and outline some prevention strategies.

Intentional replantation involves a combination of periodontics, endodontics, prosthodontics and oral surgery. Crown-root fracture management is still complicated nowadays. A fracture line extending longitudinally to the subgingival area and intruding bioogical width could affect infection control, gingival health and crown restoration. In the present study, we present two cases. Case 1 involved a 23-year-old man who presented at our hospital with crown-root fracture of the maxillary left central incisor. A radiographic image of the tooth revealed a fracture line under the alveolar crest. The fractured tooth was treated with intentional replantation with 180-degree rotation, root canal treatment and veneer restoration. The patient was followed up for 60 months. The replanted tooth functioned well, and no symptoms of resorption or ankylosis were observed by radiographic examination. Case 2 involved a 20-year-old woman who was referred to our hospital for crown-root fracture of her maxillary teeth. A radiographic examination revealed complicated crown-root fracture of the maxillary right lateral incisor and both maxillary central incisors. The central incisors were treated with intentional replantation with 180-degree rotation. At the 48-month follow-up, the fractured teeth were found to have regained normal function based on clinical and radiographic examination. Limited case reports are available on a long-term follow-up of intentional replantation with 180-degree rotation. These two cases, particularly case 2, presented optimal healing after 4 years with unideal crown-root ratios. This case report suggests that this old method of preserving teeth with crown-root fractures can be used as a last resort to save teeth owing to its timesaving and microinvasive procedure.

Objective: To investigate the efficacy of different obturation techniques on sealer penetration in teeth with internal root resorption using confocal laser microscopy.

Methods: An artificial internal resorption cavity (3 mm deep and 1.2 mm in diameter) was formed in the round-shaped root canals of 45 single-rooted teeth at a distance of 7 mm from the apex, then roots were instrumented (size 40/.06). The samples were divided into three groups (n = 15) according to the obturation technique: lateral compaction (LC), warm vertical compaction (WVC) and carrier-based (CB).

Results: In the resorption regions, the sealer penetration depth in the CB and LC groups was significantly higher than that in the WVC group (P < 0.05).

Conclusion: Within the limitations of this study, the penetration depth of the sealer in the resorption region was higher in the CB and LC groups as compared to that in the WVC group.

Objective: To explore whether hydrogen sulphide (H2S) could protect human periodontal ligament stem cells (PDLSCs) from senescence and the possible underlying mechanisms.

Methods: Cell cycle assay and Ki-67 assay were used to measure proliferation of PDLSCs. Real-time polymerase chain reaction (PCR) was used to measure cellular senescence-related p16 and p21. Calcium influx was detected by measurement of Ca2+ imaging. In addition, we analysed the possible mechanisms underlying H2S acting on PDLSCs by microarray.

Results: The cell proliferation rate of aging PDLSCs decreased significantly. The expression of cellular senescence-related p16 and p21 significantly increased in aging PDLSCs. H2S donor (GYY4137) treatment increased the proliferation rate of senescence PDLSCs. Furthermore, the donor of H2S treatment effectively prevented cell cycle arrest of PDLSCs during the aging process and inhibited the expression of cellular senescence-related markers. Mechanically, H2S donor treatment could activate the calcium influx in PDLSCs. Moreover, pretreatment with TRPV4 inhibitors significantly attenuated the calcium influx induced by H2S donor treatment in PDLSCs. It also alleviated the protective effect of H2S on the senescence of PDLSCs.

Conclusion: H2S alleviated the senescence of human PDLSCs by TRPV4 channel mediated calcium flux. These results provide a potential strategy to deal with cell aging and may facilitate cell therapy for oral diseases.

Objective: To evaluate the extension of canalis sinuosus (CS) into the alveolar crest for surgical reference in the anterior maxilla.

Methods: In this cross-sectional study, 485 CBCT images were evaluated in three orthogonal planes (axial, coronal and sagittal). The type of extension of CS into the alveolar ridge in the anterior maxilla was evaluated. The alveolar ridge was divided into four equal parts in a vertical and horizontal direction. In a vertical direction from apical to incisal and in a horizontal direction from labial to palatal, the four parts were designated as types 0, I, II and III, respectively. The extension of CS into the alveolar ridge was then traced.

Results: CS was present in 380 subjects (78.35%), and the extension type was unilateral in 217 of them (57.11%) and bilateral in 163 of them (42.89%). There was no significant relationship between incidence of CS and sex. Regarding the distribution of vertical and horizontal types, type II (the third quadrant of the ridge from apical to incisal and from labial to palatal, respectively) was significantly more prevalent than other types.

Conclusion: The most common location of CS into the alveolar ridge in both horizontal and vertical directions was type II (which is not close to the cortex). Awareness about the presence and possible locations of CS helps to reduce the risk of unjustifiable postoperative complications.