Chinese Journal of Dental Research, 02/2014

Xerostomia is becoming a major issue in dental and medical clinics with an increase of aged population. Medication is the most common etiology of xerostomia, while the most severe xerostomia generally occurs in patients with a history of head and neck radiotherapy. Xerostomic patients usually suffer from diminished quality of life due to various symptoms and complications. Decreased salivary output is a definite objective sign, but oral mucosal wetness is a more reliable factor for the evaluation of xerostomia. At present there are no effective therapeutic methods for the treatment of xerostomia. Sialogogues may have problematic side effects and their therapeutic effects last only brief duration. Artificial saliva typically does not produce satisfactory results in therapeutic efficacy. Therefore, further research and development of better therapeutic modalities are necessary. The basic concept for the development of ideal and functional artificial saliva is the mimicry of natural human saliva. We need proper candidate molecules and antimicrobial supplements to simulate the rheological and biological properties of human saliva. We also need better understanding of the interactions between the ingredients of artificial saliva themselves and between the ingredients and components of human saliva both in solution and on surface phases. In addition, we need accepted measures to evaluate the efficacy of artificial saliva. In conclusion, for the development of ideal artificial saliva, research based on the understanding of pathophysiology of xerostomia and knowledge about rheological and biological functions of human saliva are necessary. Keywords: xerostomia, dry mouth, artificial saliva, saliva substitute

Arteriovenous malformations (AVMs) are congenital vascular malformations (CVMs) resulting from birth defects of the vasculature. It is rarely seen, only accounting for 1.5% of all vascular anomalies, and 50% of the lesions are located in the oral and maxillofacial region. Regardless of the type, AVMs may ultimately lead to significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity, AVMs still remain the most challenging and/or life-threatening form of vascular anomalies. Transarterial coil embolisation or ligation of feeding arteries are incorrect approaches and may result in progress of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route, and should be abandoned. Interventional embolisation using various sclerosants is currently the mainstay of treatment for AVMs, and elimination of the nidus (if present) is the key to success. Among various embolosclerotherapy agents, ethanol sclerotherapy produces the best long-term outcomes, with minimal complications. For more complex cases, multidisciplinary approaches and interventions may provide an excellent potential for a curative result. Based on the published literature and clinical experiences, a practical treatment guideline was established in order to provide a criterion for the management of oral and maxillofacial AVMs. This protocol will be renewed and updated to reflect cutting edge knowledge, and provide the newest treatment modalities for oral and maxillofacial AVMs. Keywords: oral and maxillofacial region, arteriovenous malformations, treatment guideline

Objective: To investigate the inhibitory effects of 25-hydroxyvitamin D3 (25(OH)D3)-loaded polylactic acid (PLA) microspheres on inflammatory response in diabetic periodontitis. Methods: 25(OH)D3-loaded PLA microspheres were produced using emulsion-solvent evaporation method. Rat bone marrow stromal cells (BMSCs) cultured with Aggregatibacter actinomycetemcomitans in high glucose medium were chosen to mimic diabetic periodontitis. After cultivation with 25(OH)D3-loaded PLA microspheres, inflammation-related proteins in BMSCs were detected using Western blot analysis. Periodontitis was induced using silk ligatures in diabetic rats, and 25(OH)D3-loaded PLA microspheres were placed into the periodontal pockets. Periodontal tissues were examined using hematoxylin and eosin staining and western blot analysis. Results: Drug release from the 25(OH)D3-loaded microspheres was relatively steady during 70 days. In a diabetic periodontitis-like environment, 25(OH)D3-loaded microspheres upregulated vitamin D receptor expression, and downregulated nuclear factor-κB expression and signal transducer and activator of transcription 3 phosphorylation in the BMSCs. These 25(OH)D3 microspheres also attenuated periodontal inflammatory infiltrate and bone loss in diabetic rats with periodontitis. Conclusion: 25(OH)D3-loaded microspheres could ameliorate diabetic periodontitis by inhibiting inflammatory response, and may provide a potential therapy for patients with this disease. Keywords: 25-hydroxyvitamin D3, microsphere, inflammatory response, diabetes, periodontitis

Objective: To acquire parameters for stereotaxis of the mandibular nerve initial point of the trigemenial ganglion (TG) and to test the accuracy of the acquired parameters for microinjection into the mandibular nerve initial point of TG in adult rats. Methods: Sprague-Dawley rats (260-270 g) were mounted onto a stereotaxic frame. The bregma was set as an anchor point and the three-dimensional parameters between the mandibular nerve initial point of the bilateral TGs and the bregma were measured in 25 rats. The accuracy of these parameters was tested using microinjection of Evans blue dye into the mandibular nerve initial point of the bilateral TGs in 30 rats and the injection sites were evaluated by dissection. Results: The three-dimensional parameters of the mandibular nerve initial point of the bilateral TGs were 3.5 ± 0.1 mm posterior and 3.6 ± 0.2 mm lateral to the bregma, and 12.0 ± 0.2 mm inferior to the skull surface. Accuracy for the microinjection of Evans blue dye into the mandibular nerve initial point of the bilateral TGs was 86.7% (52/60). Conclusion: The acquired parameters served well for stereotaxis and microinjection of reagents into the mandibular nerve initial point of TG. Keywords: trigeminal ganglion, stereotaxis, orofacial pain, microinjection, temporomandibular disorders

Objects: To test the hypothesis whether bone marrow stem cells (BMSCs) could migrate into the periodontium as the precursor available for the repair of tissue injury. Methods: A chimeric mouse model was established by transplanting BMSCs derived from red fluorescent protein mouse into irradiated BALB/c mice. Subsequently, a periodontal defect was created beside the maxillary first molar and filled with ceramic bovine bone. Finally, the chimeric mice were divided into three groups and were observed 3, 14 and 28 days later respectively. The involvement of BMSCs in periodontal defects was analysed using an in vivo imaging system and immunohistochemical staining of CD45, CD105 and CD31. Cell surface marker expression in injured tissue was also compared with that in normal tissue. Results: Increasing numbers of BMSCs migrated into the periodontal defect with time. The distribution was initially limited to ceramic bovine bone and then around blood vessels and near alveolar bone. Furthermore, expression of CD105 and CD31 was much higher in injured periodontal tissue than that in healthy periodontium, although CD45 was not expressed in either of these tissues. Conclusion: BMSCs, but not haemopoietic stem cells, were involved in periodontal defect; they entered the periodontium probably via blood vessels. Keywords: bone marrow stem cell (BMSC), red fluorescent protein (RFP), periodontal ligament stem cell (PDLSC)

Objective: To evaluate morphological changes of the apical surface after root canal preparation with 1 mm beyond the apical foramen using ProTaper Universal (PTU) files, K3 files and Twisted files (TF), respectively. Methods: Seventy teeth with a centered apical foramen and 70 teeth with a deviated apical foramen were included as group A and group B respectively. In each group, 20 teeth were randomly assigned for root canal preparation with PTU, K3 and TF files, respectively; the remaining 10 teeth were used as the control group without any preparation. The apical foramens were examined with scanning electronic microscopy. The foramen integrity damage (FID) and dentin defects (DDs) were noted and compared between different groups. Results: FID and DD were significantly less in Group A. DDs was not found in the control group. Preparation with PTU, K3, and TF files caused FID in 6.67%, 10%, and 3.33% of teeth in the group A, and in 20%, 26.67%, and 10% in Group B, respectively. Preparation with PTU, K3, and TF files caused DD in 6.67%, 6.67%, and 3.33% of teeth in Group A, and in 23.33%, 26.67%, and 6.67% in Group B, respectively. PTU and K3 files produced more DDS than TF files. However, no significant difference was found between groups using PTU and K3 files. Conclusion: Rotary instrumentation caused less damage on the apical surface in foramencentered root canals than foramen-deviated root canals when working beyond the canal length. TF files had a tendency to produce less DDS compared with PTU or K3 files during over-instrumented root canals. Keywords: nickel-titanium instruments, root canal preparation, dentin defects, apical foramen, scanning electron microscopy

Objectives: To obtain maxillary anterior tooth dimension and proportion values for the Central Chinese population and to evaluate the existence of sexual dimorphism, any consistent relationships between the tooth ratios, and the presence of golden proportions. Methods: Tooth dimensions and proportions of six maxillary anterior teeth were recorded on gypsum casts obtained from 147 subjects (82 women and 65 men). Of these, 115 casts were digitally photographed in a standardised manner and apparent width values for six maxillary anterior teeth were recorded for golden proportion analysis. Existence of sexual dimorphism, any consistent width/height ratio and golden proportions were statistically analysed. One-sample t-test, two-sample t-test, and paired t-test were used to analyse the data. Results: There were no significant differences between measurements on the right and left side. Sexual dimorphism existed for various tooth dimensions. There was no statistically significant difference for width/height ratios between the two genders for central incisor and lateral incisor. However, canines showed a statistically significant difference. The golden proportion guideline was not applicable for this population. Conclusion: The maxillary anterior teeth dimensions were significantly greater for men than women; however, the mean difference was small ( 0.2 mm) and may not be clinically significant. The golden proportion, or any recurring anterior teeth proportions, was not found for the population. There was a significant difference in width/height ratio of canines between the genders, confirming its greatest gender-based morphological difference. Keywords: anterior teeth, teeth proportions, aesthetics, central chinese population, golden proportion