OBJECTIVETo explore the rotation of abutment teeth of fixed partial denture in chewing and to analyze the effect of rotation on the stability of abutment teeth.

METHODSLeft mandible (without the second premolar and the first molar) was used for specimen. Holograph-speckle interferometry was employed for measuring the rotation angle.

RESULTSThe maximal rotation angle was no more than 0.6 degrees and change of the angle was obviously in nonlinearity, when load increased from 9.8 N to 225.4 N.

CONCLUSIONSThe laser holograph-speckle interferometry could be used to measure rotation of abutment teeth. The intricate surface contacting was the main reason for rotation and this rotation had no bad effect on abutment teeth of fixed partial denture in daily use.

Adult ; Dental Abutments ; Denture, Partial, Fixed ; Humans ; Interferometry ; methods ; Male ; Rotation

PURPOSE: To analyze the relationship between ocular surface disease index and tear film lipid layer thickness (LLT) using a LipiView II® (LipiView® Ocular Surface Interferometer, TearScience®, Morrisville, NC, USA) interferometer. METHODS: Forty-nine patients diagnosed with dry eye syndrome were recruited for this prospective study. Patients completed ocular surface disease index questionnaires. We performed slit lamp examination, Schirmer test, corneal and conjunctival fluorescein staining, measured tear film break-up time, and graded meibomian gland dysfunction. Tear LLT, blinking time, and dynamic meibomian imaging were analyzed using a LipiView II® ocular interferometer. To control for missing data, we analyzed four sets of imputated data via the multiple imputation method and performed Pearson correlation analysis. Patients were assigned to one of two LLT categories (LLT < 60 or LLT ≥ 60) and Chi-square test was performed. RESULTS: Among ocular surface disease parameters, tear film break-up time (tBUT) had a statistically significant correlation with average and maximum LLT (average LLT; p = 0.008, 0.035, 0.006, 0.049, maximum LLT; p = 0.006, 0.042, 0.020, 0.049, Pearson correlation analysis with multiple imputation) but there was no significant correlation with minimum LLT (minimum LLT; p = 0.048, 0.090, 0.079, 0.039). Of the patients with a relatively thick average LLT or maximum LLT (LLT ≥ 60 nm), 80% and 88% had a tBUT < 10, respectively. Conversely, 39% and 47% of patients with relatively thin average LLT (LLT < 60 nm) had a tBUT < 10 (average LLT; p = 0.013, maximum LLT; p = 0.039). CONCLUSIONS: Average LLT and maximum LLT were significantly correlated with tBUT. Patients with a relatively thin average or maximum LLT tended to have a shorter tBUT. Based on these results, measuring tear film LLT using a LipiView II® interferometer may be useful in the diagnosis and follow-up of patients with evaporative dry eye.
Blinking ; Diagnosis ; Dry Eye Syndromes ; Fluorescein ; Follow-Up Studies ; Humans ; Interferometry ; Meibomian Glands ; Methods ; Prospective Studies ; Slit Lamp ; Tears*

PURPOSE: To evaluate the refractive predictability of a partial coherence interferometry (PCI) biometry device (IOL Master(R)) for cataract surgery and to investigate factors that may affect it. METHODS: Retrospective review of 209 eyes from 151 patients that had undergone preoperative PCI biometry and an uneventful phacoemulsification cataract surgery with posterior chamber intraocular lens (IOL) implantation was conducted. Prediction error defined as the intended refraction minus the postoperative refraction in spherical equivalent (SE) and the absolute error were analyzed according to IOL calculation formulas, patient characteristics, preoperative visual acuity (VA) and refraction, posterior subcapsular cataract (PSC), signal-to-noise ratio (SNR), and axial length (AL). RESULTS: The overall refractive predictability of the PCI device was good. Generally, the SRK/T formula performed better than the SRK-II formula. Refractive predictability was slightly worse in eyes with > or =+2.0 diopters (D) of preoperative SE (with both SRK-II and SRK/T) and in eyes with an AL< or =23.0 mm (only with SRK-II. No other factors significantly affected the refractive predictability of the PCI, although poor VA, dense PSC, and poor SNR were closely interrelated. CONCLUSIONS: The SRK/T formula performed significantly better than the SRK-II formula. Eyes with an AL< or =23.0 mm were associated with significantly greater hyperopic shifts in postoperative refraction with the SRK-II formula, but not with the SRK/T formula. A preoperative SE> or =+2.0D was related to a significantly greater hyperopic shift in postoperative refraction. With proper verification of measured data and a suitable IOL calculation formula, good refractive predictability is expected from PCI biometry regardless of patient characteristics, preoperative VA, SNR, PSC, and AL.
Aged ; Aged, 80 and over ; Female ; Humans ; Interferometry/*methods ; Lens Implantation, Intraocular ; *Lenses, Intraocular ; Light ; Male ; Phacoemulsification/*methods ; *Refraction, Ocular ; Refractive Errors/*diagnosis/physiopathology ; Reproducibility of Results ; Retrospective Studies ; Visual Acuity

PURPOSE: To compare the refractive results of cataract surgery measured by applanation ultrasound and the new partial coherence interferometer, AL-scan. METHODS: Medical records of 76 patients and 104 eyes who underwent cataract surgery from January 2013 to June 2013 were retrospectively reviewed. Biometries were measured using ultrasound and AL-scan and intraocular lens power was calculated using the SRK-T formula. Automatic refraction examination was done 1 month after the operation, and differences between the ultrasound group and AL-scan group were compared and analyzed by mean absolute error. RESULTS: Mean axial length measured preoperatively by the ultrasound method was 23.53 +/- 1.17 mm while the lengths measured using the AL-scan were 0.03 mm longer than that of the ultrasound group (23.56 +/- 1.15 mm). However, there was not a significant difference in this finding (p = 0.638). Mean absolute error was 0.34 +/- 0.27 diopters in the ultrasound group and 0.36 +/- 0.31 diopters in AL-scan group, which showed no significant difference (p = 0.946) in precision of predicting postoperative refraction. CONCLUSIONS: Although the difference was not statistically significant, intraocular lens calculations done by the AL-scan were nearly similar in predicting postoperative refraction compared to those of applanation ultrasound, however more precise measurements may be obtained if the axial length is longer than 24.4 mm. Except in the case of opacity in the media, which makes obtaining measurements with the AL-scan difficult, AL-scan could be a useful biometry in cataract surgery.
Aged ; Anterior Chamber/pathology ; Axial Length, Eye/*pathology ; Biometry/methods ; Female ; Humans ; Interferometry/*instrumentation ; *Lens Implantation, Intraocular ; Lenses, Intraocular ; Light ; Male ; Middle Aged ; *Phacoemulsification ; Refraction, Ocular/physiology ; Reproducibility of Results ; Retrospective Studies ; Visual Acuity/physiology