ABSTRACT
Objective: To investigate the influence of light and heavy bite force on the mandibular movement trajectories, and the influence of bite force on virtual occlusal pre-adjustment of digital full crown. Methods: From October 2021 to March 2022, 10 postgraduate volunteers (3 males and 7 females, aged 22-26 years) were recruited from Peking University School and Hospital of Stomatology. Maxillary and mandibular digital models of the participants were obtained by intraoral scanning. Jaw relations were digitally transferred under heavy bite force and mandibular movement trajectories under light and heavy bite force were recorded by jaw motion analyser. Three mandibular markers were chosen, namely the mesial proximal contact point of the central incisor (incisal point) and the mesial buccal cusp tips of the bilateral first molars. The three-dimensional displacements of the markers under two kinds of bite force in the intercuspal position (ICP), the sagittal projection of the three-dimensional displacements in the protrusive edge-to-edge position, and the coronal projection of the three-dimensional displacements in the lateral edge-to-edge position of upper and lower posterior teeth were measured. Single-sample t-test was used to compare the three-dimensional displacements and the corresponding sagittal projection and coronal projection with 0, respectively. The left maxillary central incisor and left mandibular first molar were virtually prepared by the reverse engineering software. Then dental design software was used to design digital full crown using the copy method. The mandibular movement trajectories under light and heavy bite force were separately used to guide virtual occlusal pre-adjustment. The three-dimensional deviations (mean deviations and root mean square) between the lingual surface of the left maxillary central incisor or the occlusal surface of the left mandibular first molar and that of the natural tooth before preparation were calculated (light bite force group and heavy bite force group), and the differences between the two groups were compared by the paired t-test. Results: Under the two kinds of bite force, the three-dimensional displacements of the markers in the ICP were (0.217±0.135), (0.210±0.133) and (0.237±0.101) mm, respectively; the sagittal projection of the three-dimensional displacements of the markers in the protrusive edge-to-edge position were (0.204±0.133), (0.288±0.148) and (0.292±0.136) mm, respectively; the coronal projection of the three-dimensional displacements of the mesial buccal cusp tips of the bilateral first molars in the lateral edge-to-edge position were (0.254±0.140) and (0.295±0.190) mm, respectively. The differences between the above displacements and 0 were statistically significant (P<0.05). The results of occlusal pre-adjustment showed that the mean deviations of the lingual surface of the left maxillary central incisor in the light and heavy bite force groups were (0.215±0.036) and (0.195±0.041) mm (t=3.95, P=0.004), respectively. The mean deviations of the occlusal surface of the left mandibular first molar were (0.144±0.084) and (0.100±0.096) mm (t=0.84, P=0.036), respectively. Conclusions: Both the light and heavy bite force have an influence on the mandibular movement trajectories. Virtual occlusal pre-adjustment of prostheses with mandibular movement trajectories under heavy bite force can obtain morphology of lingual or occlusal surfaces closer to the natural teeth before preparation.
Subject(s)
Male , Female , Humans , Bite Force , Tooth , Mandible , Molar , Occlusal AdjustmentABSTRACT
Copy number aberrations (CNAs) in chromosome arm 8q have been associated with unfavorable clinical outcomes of several cancers and progressive tumor characteristics of hepatocellular carcinoma (HCC).This study was to identify correlation of CNAs in 8q with clinical outcomes of HCC patients,and further screen for differentially expressed genes in outcome-related CNAs.Array comparative genomic hybridization and expression arrays were performed to detect CNAs and expression levels,respectively.The correlations between CNAs in 8q and outcomes were analyzed in 66 patients,with a median follow-up time of 45.0 months (range,2.6-108.6 months).One hundred and nine cases were further evaluated to identify differentially expressed genes in the potential outcome-related CNAs.Copy number gain in 8q was observed in 22 (33.3 ％) of the 66 HCC cases.The most recurrent gains (with frequencies ＞20％) were 8q13.3-21.3,8q21.3-23.3,8q23.3-24.13,8q24.13-24.3,and 8q24.3.Survival analysis showed that 8q24.13-24.3 gain was significantly associated with reduced overall survival (P=0.010).Multivariate Cox analysis identified 8q24.13-24.3 gain as an independent prognostic factor for poor overall survival (HR=2.47;95％CI=1.16-5.26;P=0.019).A panel of 17 genes within the 8q24.13-24.3 region,including ATAD2,SQLE,PVT1,ASAP1,and NDRG1 were significantly upregulated in HCCs with 8q24.13-24.3 gain compared to those without.These results suggest that copy number gain at 8q24.13-24.3 is an unfavorable prognostic marker for HCC patients,and the potential oncogenes ATAD2,SQLE,PVT1,ASAP1,and NDRG1 within the regional gain,may contribute coordinately to the 8q24.13-24.3 gain-related poor prognosis.
ABSTRACT
Copy number aberrations (CNAs) in chromosome arm 8q have been associated with unfavorable clinical outcomes of several cancers and progressive tumor characteristics of hepatocellular carcinoma (HCC).This study was to identify correlation of CNAs in 8q with clinical outcomes of HCC patients,and further screen for differentially expressed genes in outcome-related CNAs.Array comparative genomic hybridization and expression arrays were performed to detect CNAs and expression levels,respectively.The correlations between CNAs in 8q and outcomes were analyzed in 66 patients,with a median follow-up time of 45.0 months (range,2.6-108.6 months).One hundred and nine cases were further evaluated to identify differentially expressed genes in the potential outcome-related CNAs.Copy number gain in 8q was observed in 22 (33.3 ％) of the 66 HCC cases.The most recurrent gains (with frequencies ＞20％) were 8q13.3-21.3,8q21.3-23.3,8q23.3-24.13,8q24.13-24.3,and 8q24.3.Survival analysis showed that 8q24.13-24.3 gain was significantly associated with reduced overall survival (P=0.010).Multivariate Cox analysis identified 8q24.13-24.3 gain as an independent prognostic factor for poor overall survival (HR=2.47;95％CI=1.16-5.26;P=0.019).A panel of 17 genes within the 8q24.13-24.3 region,including ATAD2,SQLE,PVT1,ASAP1,and NDRG1 were significantly upregulated in HCCs with 8q24.13-24.3 gain compared to those without.These results suggest that copy number gain at 8q24.13-24.3 is an unfavorable prognostic marker for HCC patients,and the potential oncogenes ATAD2,SQLE,PVT1,ASAP1,and NDRG1 within the regional gain,may contribute coordinately to the 8q24.13-24.3 gain-related poor prognosis.