Objective To investigate the application value of slice encoding for metal artifact correction-view angle tilting(SEMAC-VAT)in chronic hip pain after total hip arthroplasty(THA).Methods A total of 22 patients who underwent TH A and required MRI reassessment for chronic hip pain were enrolled.All patients underwent coronal and axial short time inversion recovery(STIR)and SEMAC-VAT sequence scans.The prosthesis and surrounding artifact areas of STIR sequence and SEMAC-VAT sequence images were measured respectively.Likert scores were assigned to evaluate prosthesis clarity and visibility of surrounding anatomical structures.The number of abnormal lesions detected was recorded.Paired t-test and rank-sum test were used for comparisons between groups.Results Among the 22 patients,the mean prosthesis and surrounding artifact areas measured in coronal and axial STIR sequences were(73.08±11.28)cm2 and(34.36±8.47)cm2,respectively.For SEMAC-VAT sequences,the corresponding values were(44.30±8.41)cm2 and(23.08±5.85)cm2,respectively.These differences were statistically significant(t=13.942,8.659,P＜0.05).SEMAC-VAT sequences had higher Likert scores on coronal and axial prosthesis clarity and surrounding anatomical structures visibility than STIR sequences(P＜0.05).Additionally,SEMAC-VAT sequences were more effective in detecting abnormal lesions than STIR sequences(P＜0.05).Conclusion Compared to STIR sequences,SEMAC-VAT sequences significantly reduce metal artifacts and enhance image quality in the assessment of chronic hip pain after THA.This technique is advantageous in detecting more positive signs,facilitating the evaluation of hip images in patients with chronic pain after TH A,and subsequently clarifying the etiology of pain.

The problems caused by proximal contact loss(PCL)of dental implants have been a mainstream research topic in recent years,and scholars are unanimously committed to analyzing their causes and related factors,aiming to identify solutions to the problems related to PCL.The effects of the anterior component of force(ACF),the lifelong re-molding of the adult craniofacial jaw and alveolar socket,and the osseointegration characteristics of dental implants are the main causes of PCL.On the one hand,the closing movement of the mandible causes the ACF of the tooth to move through the posterior molar cusp.Moreover,drifting between the upper and lower posterior teeth and mandibular anteri-or teeth can cause the anterior teeth of the upper and lower jaws to be displaced labially.On the other hand,reconstruc-tion of the jaw,alveolar socket and tooth root,the forward horizontal force of the masticatory muscles,the dynamic com-ponent of the jaw and the forward force generated by the oblique plane of the tooth cusp can cause the natural tooth to experience near-middle drift.Additionally,natural teeth can shift horizontally and vertically and rotate to accommodate remodeling of the stomatognathic system and maintain oral function.Nevertheless,the lack of a natural periodontal mem-brane during implant osseointegration,the lack of a physiological basis for near-medium drift,the small average degree of vertical motion and the integrated silence of dental implants without the overall drift characteristics of natural teeth increases the probability of PCL.The high incidence of PCL is clearly associated with the duration of prosthesis delivery and the mesial position;but it is also affected by the magnitude of the bite force,occlusion,the adjacent teeth,restora-tion design,implant location,jaw,and patient age and sex.PCL has shown a significant correlation with food impaction,but not a one-to-one correspondence,and did not meet the necessary and sufficient conditions.PCL is also associated with peri-implant lesions as well as dental caries.PCL prevention included informed consent,regular examinations,se-lection of retention options,point of contact enhancement,occlusal splints,and the application of multipurpose digital crowns.Management of the PCL includes adjacent contact point additions,orthodontic traction,and occlusal adjust-ment.Existing methods can solve the problem of food impaction in the short term with comprehensive intervention to seek stable,long-term effects.Symmetric and balanced considerations will expand the treatment of issues caused by PCL.