[Risk factors and nutritional status analysis in patients with liver cirrhosis and concomitant chronic periodontitis].

Objective: To study and explore the prevalence, characteristics, preliminary risk factors, as well as their relationship with nutritional scores in liver cirrhotic patient with chronic periodontitis. Methods: 163 patients with liver cirrhosis who were hospitalized in the Hepatology Division, Department of Internal Medicine at Tianjin Third Central Hospital from June to September 2018 were enrolled as the case group, while the control group consisted 140 healthy individuals enrolled during the same period. Periodontal examination, biochemical examination and oral hygiene habits were investigated. The prevalence of periodontitis in the two groups was compared, and the risk factors of severe periodontitis were conducted by multivariate regression analysis. Results: The prevalence of chronic periodontitis was significantly higher in patients with liver cirrhosis than healthy control population, and the differences were statistically significant (P < 0.05). The prevalence of severe periodontitis and full edentulous jaws was significantly higher in patients with liver cirrhosis than healthy control group, and the differences were statistically significant (P < 0.05 and P < 0.001). Compared with the healthy control group, the depth of periodontal pocket and the degree of attachment loss were significantly increased in the liver cirrhosis group (P < 0.001). Multivariate regression analysis showed that liver cirrhosis was the independent risk factors for both groups of patients with severe periodontitis (χ (2) = 11.046, P < 0.001). Univariate and multivariate regression analysis showed that toothbrushing frequency, nutritional risk score, prealbumin level and Child-Pugh grade were independent risk factors for occurrence of severe periodontitis in liver cirrhotic patient (χ (2) = 5.252, P = 0.022; χ (2) = 24.162, P < 0.001; χ (2) = 4.159, P = 0.041; χ (2) = 9.249, P = 0.002). Conclusion: The prevalence of periodontitis is significantly higher in patients with liver cirrhosis than healthy individuals, and liver cirrhosis is an independent risk factor for the occurrence of severe periodontitis. Toothbrushing frequency, nutritional risk score, prealbumin level and Child-Pugh grade are risk factors for severe periodontitis in patients with liver cirrhosis.

[Three-dimensional finite element analysis of four-implants supported mandibular overdentures using two different attachments].

Objective: To compare the biomechanical characteristics of four-implants mandibular overdentures supported by Locator attachment or bar-clip attachment under different mechanical loads using three-dimensional finite element analysis method. Methods: Two different models of four-implants supported mandibular overdentures using Locator attachment and bar-clip attachment (hereinafter called Locator model and bar-clip model) were established. Each model was subjected to five different mechanical loading conditions: 100 N vertical loading in central incisor (vertical load of incisor), 100 N vertical loading or oblique loading in canine (vertical or oblique loads of canines), 100 N vertical or oblique loading in mandibular first molar (vertical or oblique loads of mandibular first molar). The stress distributions in implants, peri-implant bone and mucosa were recorded under the above five conditions to evaluate the effects of different attachments on the biomechanical properties of implant-supported mandibular overdentures. Results: Regardless of loading conditions and types of attachments, the stress concentration in implants were located at the neck of implants, and the stress concentration in peri-implant bone was located in the cortical bone. The stress values in mucosa were always much smaller than those in implants and cortical bone. Regardless of loading positions (on canine or on mandibular first molar), the maximum stress at the bone interface around the implant under lateral loading was much higher than that under vertical loading. Under various loading conditions, the stress in implants and cortical bone of the Locator model (the highest von Mise stress value was respectively 79.5 and 22.3 MPa) were lower than that of bar-clip model (the highest von Mise stress value was 110.3 and 28.7 MPa respectively) while the maximum compressive stress in mucosa (0.198 MPa) in Locator model was slightly higher than that in the bar-clip model (0.137 MPa). Conclusions: In clinical practice, the lateral force applied to the implant-retained overdenture should be minimized to avoid complications caused by pathological loads. Under the same loading condition, the stress distributions in overdenture using Locator attachment are more dispersed, which is more conducive to long-term stability of implants.

Pathways involved in the spread of buccal carcinoma on contrast-enhanced multislice CT.

OBJECTIVES: To explore how buccal carcinoma spread, using contrast-enhanced multislice CT (CEMSCT). METHODS: We retrospectively analysed the extent of lesions in 56 patients with primary buccal squamous cell carcinoma (SCCA). Abnormal manifestations on CEMSCT at oral subsites and involved adjacent structures were documented and evaluated, which were compared with the results of surgery and histopathology. RESULTS: Infiltration and spread to oral subsites and/or adjacent structures was confirmed in 33 patients (58.9%). The opening of the Stensen duct was the most commonly invaded oral subsite (72.7%); other sites included the gingivobuccal sulcus (60.6%), pterygomandibular raphe (54.5%), gingiva (24.2%), retromolar trigone (24.2%), orbicularis oris (18.2%) and the floor of mouth (15.2%). Of the involved adjacent structures, the buccal space was the most common site of spread (69.7%), followed by the masticatory muscles and spaces (57.6%), bone (54.5%), skin and subcutaneous fat (39.4%), pharynx (30.3%), investing fascia (15.2%) and the base of the skull (6.1%). CEMSCT manifestations of the involvement in buccal SCCAs had correlations with pathological findings (p < 0.05). The sensitivities, specificities and accuracies of two radiologists' evaluation on buccal carcinoma involvement were 50.00%, 23.21% and 73.21%; and 51.79%, 32.14% and 83.93%, respectively. CONCLUSIONS: Buccal SCCAs could superficially and deeply spread to multiple oral subsites and/or adjacent structures. CEMSCT could delineate their spread pathways and extents.