Survival analysis of crown margin repair: A retrospective study in a dental school setting

BackgroundRepairing crowns with defective margins is minimally invasive and cost-effective compared with replacement. The authors’ objectives were to examine the survival trajectory of crown margin repairs and to determine the factors associated with survival.MethodsRecords of adult patients from January 2008 through August 2019 were reviewed for crown margin repairs completed at University of Iowa College of Dentistry. A total of 1,002 crown margin repairs were found. Each repair was followed through the end of study in 2019 or until an event (for example, additional repair, endodontic treatment, crown replacement, or extraction). A Cox proportional hazards model was used to study the relationship between selected covariates and time to event.ResultsDuring the follow-up period, 32.8% of the repairs needed reintervention. In the final model, repair material was the only significant covariate. No difference was found between the survival of repairs done with resin-modified glass ionomer and amalgam. However, the repairs done with resin-based composite and conventional glass ionomer were more likely (1.5 times: 95% CI, 1.02 to 2.10 times; and 2 times: 95% CI, 1.40 to 2.73 times, respectively) to need reintervention than were those done with amalgam.ConclusionsMedian survival time of crown margin repairs was 5.1 years (95% CI, 4.48 to 5.72 years). Median survival times for amalgam, resin-modified glass ionomer, resin-based composite, and glass ionomer repair materials were 5.7 years (95% CI, 4.80 to 6.25 years), 5.3 years (95% CI, 4.73 to 6.34 years), 3.2 years (95% CI, 2.51 to 6.19 years), and 3.0 years (95% CI, 2.53 to 3.62 years), respectively.Practical ImplicationsWhen considering crown margin repairs, resin-modified glass ionomer or amalgam is preferable to resin-based composite or glass ionomer.     

圆锥型套筒冠修复体修复治疗对牙周病患者牙龈指数、龈乳头探诊出血指数、牙周探诊深度的影响

目的 探讨圆锥型套筒冠修复体修复治疗对牙周病患者牙龈指数、龈乳头探诊出血指数、牙周探诊深度的影响。方法 选取2017年3月～2019年3月我院收治的牙周病患者60例,随机分为对照组和研究组两组。对照组进行常规治疗,研究组进行圆锥型套筒冠修复体修复治疗。比较两组患者疗效、牙齿松动度(TM)、牙龈指数(GI)、龈乳头探诊出血指数(PBI)、牙周探诊深度(PD)、改良菌斑指数(mPLI)、改良龈沟出血指数(MSBI)、牙龈乳头指数(PIS)、白细胞介素-8(IL-8)、白细胞介素-2(IL-2)水平、口腔健康影响程度评分(OHIP-14)、咀嚼功能、满意率。结果 研究组有效率高于对照组(P0.05);研究组TM、GI、PBI、PD低于对照组(P0.05);研究组mPLI、MSBI、PIS低于对照组(P0.05);研究组IL-8、IL-2水平低于对照组(P0.05);研究组OHIP-14评分低于对照组(P0.05);研究组咀嚼功能高于对照组(P0.05);研究组修复满意率高于对照组(P0.05)。结论 牙周病治疗中,圆锥型套筒冠修复体修复疗效显著,应在临床上广泛推广与应用。     

The effect of immediate postpartum levonorgestrel contraceptive implant use on breastfeeding and infant growth: a randomized controlled trial

Objective

This study assessed whether immediate postpartum insertion of levonorgestrel contraceptive implants is associated with a difference in infant growth from birth to 6 months, onset of lactogenesis, or breastfeeding continuation at 3 and 6 months postpartum compared to delayed insertion at 6 to 8 weeks postpartum.

种植基台背景色及粘接剂颜色对不同厚度高透氧化锆修复体颜色的影响研究

 目的　研究种植基台背景色及粘接剂颜色对3种不同厚度高透氧化锆修复体颜色的影响，为粘接剂的选择提供指导方案。方法　制备不同厚度（1.5、2.0、2.5 mm）的高透氧化锆修复体各20个。将3种厚度修复体分别使用3种颜色粘接剂粘接于喷砂后的种植基台上，记为1.5 mm透明、有色、白色研究组，2.0 mm透明、有色、白色研究组，2.5 mm透明、有色、白色研究组；将未粘接于种植基台上的3种厚度修复体记为1.5 、2.0 和2.5 mm对照组；每组修复体各5个。应用VITA Easyshade Ⅴ比色仪测量各组修复体的色彩参数（CIE L*a*b*），并计算粘接前后修复体的色差值（ΔE），对比肉眼可察觉阈值和临床可接受阈值，以评价种植基台背景色及粘接剂颜色对不同厚度修复体颜色的影响程度。结果　（1）种植基台背景色对不同厚度修复体颜色的影响分析：1.5 mm透明研究组ΔE（8.51）高于临床可接受阈值；2.0 mm透明研究组ΔE（2.03）低于临床可接受阈值，但高于肉眼可察觉阈值；2.5 mm透明研究组ΔE（1.26）低于肉眼可察觉阈值。（2）粘接剂颜色对不同厚度修复体颜色的影响分析：当修复体厚度为1.5 mm时，仅有色研究组ΔE低于临床可接受阈值，但仍高于肉眼可察觉阈值，且不同粘接剂组间ΔE比较，差异有统计学意义（F = 21.941，P < 0.05）；当修复体厚度为2.0 mm时，不同粘接剂组间ΔE比较，差异有统计学意义（F = 13.683，P < 0.05），且均低于临床可接受阈值，仅有色研究组ΔE低于肉眼可察觉阈值，但有色研究组ΔE与透明研究组ΔE比较，差异无统计学意义（P > 0.05）；当修复体厚度为2.5 mm时，不同粘接剂组间ΔE比较，差异无统计学意义（F = 0.683，P > 0.05），且均低于肉眼可察觉阈值。结论　种植基台背景色及粘接剂颜色均会对较薄高透氧化锆修复体的颜色造成影响。在种植义齿修复过程中，当设计的修复体厚度< 2.5 mm时，推荐使用与修复体颜色一致的有色粘接剂；当修复体厚度≥ 2.5 mm时，种植基台背景色和粘接剂颜色对修复体颜色的影响较小，3种粘接剂均可使用。     

Comparison between conventional CT and grayscale inversion CT images in the assessment of the post-operative spinal orthopaedic implants

AimTo compare the accuracy of the inverted greyscale CT versus the conventional CT in the assessment of post-operative spinal orthopaedic implants and osseous fusion.Methods50 patients who had CT as part of their routine spinal implant follow up were evaluated for the presence of fusion, fracture and loosening with conventional CT and with greyscale inverted CT images. 3 independent observers assessed the images 2 months apart. Diagnostic performance (sensitivity and specificity) of the conventional and greyscale inversion images relative to the reference standard were calculated. Agreement with the reference standard was assessed using Cohen's kappa for conventional and greyscale inversion images.ResultsCorrect classifications increased when using the greyscale inverted CT images for each reader compared to conventional CT images (40–46, 39 to 42 and 41 to 44 (out of 50)). Inverted images demonstrated better agreement with the reference standard than conventional grayscale images for assessment of fusion (kappa of 0.588 for inverted CT versus 0.484 for conventional CT) and loosening (kappa 0.386 for inverted versus 0.293 for conventional). Sensitivity was increased for assessment of fusion and loosening. McNemar's test performed for assessment of sensitivity differences showed statistical significance (p = 0.038 for fusion and p = 0.0313 for loosening).ConclusionGreyscale inversion CT is a useful adjunct which has advantages (improved sensitivity and better agreement) over conventional CT imaging in cases of fusion and loosening of metallic implants following spinal instrumentation. We recommend the use of both the greyscale inversion CT images and conventional CT imaging when assessing post-operative spinal orthopaedic implants.