Objective:To explore the effect of carboxylated polyamidoamine (PAMAM-COOH) in combination with magnesium ions on the remineralization ability of amorphous calcium phosphate (ACP) in inducing remineralization of dentin collagen fibers in a 50% ethanol solution.Methods:Forty-five intact third molars extracted for impaction reasons were obtained from the College & Hospital of Stomatology, Guangxi Medical University. Two types of demineralized dentin specimens were prepared: ①Fully demineralized dentin ( n=30), specimens were immersed in 17% ethylenediaminetetraacetic acid (EDTA) (pH=7.4) at room temperature for 14 days with daily solution refreshment; ②Partially demineralized dentin ( n=15), specimens were treated with 37% phosphoric acid gel (Ultra-Etch, Ultradent) for 15 seconds followed by thorough rinsing with deionized water. Three remineralization groups were established for demineralized dentin treatment: ①Control group, 50% ethanol solution; ②ACMP group, 50% ethanol solution containing amorphous magnesium calcium phosphate (ACMP); ③PAMAM-COOH/ACMP group, 50% ethanol solution incorporating carboxylated polyamidoamine dendrimer-modified ACMP (PAMAM-COOH/ACMP). The chemical composition of remineralization solutions was analyzed by Fourier-transform infrared spectrum (FTIR). The morphology and particle size distribution of nanoparticles were characterized using transmission electron microscope (TEM). The fully demineralized dentin specimens were treated with three different remineralization solutions (37 ℃ for 7 days) respectively. The mineralization of the dentin collagen fibers surface was observed using scanning electron microscope (SEM) and the distribution of minerals inside and outside the collagen fibers was examined by using TEM. The partially demineralized dentin specimens were treated with fluorescence-labeled remineralization solutions (37 ℃ for 7 days) respectively, followed by analysis using confocal laser scanning microscopy (CLSM) to quantitatively evaluate the penetration depth of the mineralization agents. Results:FTIR analysis confirmed the presence of characteristic absorption peaks corresponding to phosphate (PO 43-) groups, carbon-nitrogen bonds, and amide linkages in the PAMAM-COOH/ACMP nanocomposite. TEM observed that the PAMAM-COOH/ACMP nanoparticles exhibited an average particle size of (36.85±8.02) nm in an amorphous state. SEM observation indicates continuous mineral deposition on dentin collagen fibers in the PAMAM-COOH/ACMP group, while no mineral deposition in the control group and only minimal deposition in the ACMP group. TEM showed no mineral deposition inside or outside the collagen fibers in the control group, only external mineral deposition in the ACMP group, and high-density mineral deposition both inside and outside the fibers in the PAMAM-COOH/ACMP group. CLSM analysis revealed a statistically significant difference ( P<0.05) in the depth of mineralized substances entering dentin tubules between ACMP group and PAMAM-COOH/ACMP group. Conclusions:The remineralization system of 50% ethanol solution incorporating PAMAM-COOH/ACMP successfully achieved the internal and external mineralization of demineralized dentin collagen fibers.

Objective:To investigate the changes in accommodative facility after implantation of V4c implantable collamer lens (ICL) using the intelligent flipper (iFLIP).Methods:A serial case-control study was conducted.Forty patients (80 eyes) who underwent ICL implantation of V4c for myopia correction and completed the follow-up were enrolled at the Affiliated Hospital of Guizhou Medical University from April 2022 to April 2023.Monocular and binocular accommodative facility, adjustment time, and relaxation time were measured with iFLIP before operation and at 1 week, 1 month, 3 months, and 6 months after operation.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Affiliated Hospital of Guizhou Medical University (No.2023-983).Written informed consent was obtained from each subject.Results:Monocular and binocular uncorrected visual acuity at 1 week, 1 month, 3 months and 6 months after surgery were significantly improved compared with before surgery, and the differences were statistically significant (all P<0.05).Monocular and binocular postoperative accommodative facility gradually increased over time, and the increase gradually decreased and gradually stabilized.Before operation and 1 week, 1 month, 3 months, and 6 months after operation, the monocular accommodative facility was (7.99±3.42), (10.19±4.25), (12.03±4.24), (13.10±4.66) and (13.64±4.40)cpm, and the binocular accommodative facility was (9.01±3.63), (9.56±3.38), (11.58±4.00), (13.31±3.64), and (14.03±3.72)cpm, respectively, with statistically significant overall differences ( F=24.02, 14.46; both P<0.001).Monocular accommodative facility was higher than before surgery at each time point after surgery, and was higher than 1 week after surgery at 1, 3, and 6 months after surgery, with statistically significant differences (all P<0.05).Binocular accommodative facility was higher at 1, 3, and 6 months after surgery than that before surgery and 1 week after surgery, and higher at 3 and 6 months after surgery than that at 1 month after surgery, with statistically significant differences (all P<0.05).With the extension of postoperative time, the monocular and binocular adjustment time and relaxation time gradually shortened, and the shortening gradually decreased and stabilized.Monocular adjustment time and relaxation time were shorter than before surgery at all time points after surgery.The monocular adjustment time was shorter at 1, 3 and 6 months after surgery than that at 1 week after surgery and shorter at 3 and 6 months after surgery than that at 1 month after surgery, and the monocular relaxation time was shorter at 3 and 6 months after surgery than that at 1 week after surgery, and the differences were statistically significant (all P<0.05).The binocular adjustment time was shorter at 1, 3 and 6 months after surgery than before surgery and at 1 week after surgery, shorter at 3 and 6 months after surgery than at 1 month after surgery and the binocular relaxation time was shorter at all time points after surgery than that before surgery, showing statistically significant differences (all P<0.05). Conclusions:After ICL implantation, uncorrected visual acuity, accommodative facility, adjustment time and relaxation time all improve throughout the preoperative period and eventually stabilize.

Objective:To investigate the changes in accommodative facility after implantation of V4c implantable collamer lens (ICL) using the intelligent flipper (iFLIP).Methods:A serial case-control study was conducted.Forty patients (80 eyes) who underwent ICL implantation of V4c for myopia correction and completed the follow-up were enrolled at the Affiliated Hospital of Guizhou Medical University from April 2022 to April 2023.Monocular and binocular accommodative facility, adjustment time, and relaxation time were measured with iFLIP before operation and at 1 week, 1 month, 3 months, and 6 months after operation.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Affiliated Hospital of Guizhou Medical University (No.2023-983).Written informed consent was obtained from each subject.Results:Monocular and binocular uncorrected visual acuity at 1 week, 1 month, 3 months and 6 months after surgery were significantly improved compared with before surgery, and the differences were statistically significant (all P<0.05).Monocular and binocular postoperative accommodative facility gradually increased over time, and the increase gradually decreased and gradually stabilized.Before operation and 1 week, 1 month, 3 months, and 6 months after operation, the monocular accommodative facility was (7.99±3.42), (10.19±4.25), (12.03±4.24), (13.10±4.66) and (13.64±4.40)cpm, and the binocular accommodative facility was (9.01±3.63), (9.56±3.38), (11.58±4.00), (13.31±3.64), and (14.03±3.72)cpm, respectively, with statistically significant overall differences ( F=24.02, 14.46; both P<0.001).Monocular accommodative facility was higher than before surgery at each time point after surgery, and was higher than 1 week after surgery at 1, 3, and 6 months after surgery, with statistically significant differences (all P<0.05).Binocular accommodative facility was higher at 1, 3, and 6 months after surgery than that before surgery and 1 week after surgery, and higher at 3 and 6 months after surgery than that at 1 month after surgery, with statistically significant differences (all P<0.05).With the extension of postoperative time, the monocular and binocular adjustment time and relaxation time gradually shortened, and the shortening gradually decreased and stabilized.Monocular adjustment time and relaxation time were shorter than before surgery at all time points after surgery.The monocular adjustment time was shorter at 1, 3 and 6 months after surgery than that at 1 week after surgery and shorter at 3 and 6 months after surgery than that at 1 month after surgery, and the monocular relaxation time was shorter at 3 and 6 months after surgery than that at 1 week after surgery, and the differences were statistically significant (all P<0.05).The binocular adjustment time was shorter at 1, 3 and 6 months after surgery than before surgery and at 1 week after surgery, shorter at 3 and 6 months after surgery than at 1 month after surgery and the binocular relaxation time was shorter at all time points after surgery than that before surgery, showing statistically significant differences (all P<0.05). Conclusions:After ICL implantation, uncorrected visual acuity, accommodative facility, adjustment time and relaxation time all improve throughout the preoperative period and eventually stabilize.

Objective:To explore the effect of carboxylated polyamidoamine (PAMAM-COOH) in combination with magnesium ions on the remineralization ability of amorphous calcium phosphate (ACP) in inducing remineralization of dentin collagen fibers in a 50% ethanol solution.Methods:Forty-five intact third molars extracted for impaction reasons were obtained from the College & Hospital of Stomatology, Guangxi Medical University. Two types of demineralized dentin specimens were prepared: ①Fully demineralized dentin ( n=30), specimens were immersed in 17% ethylenediaminetetraacetic acid (EDTA) (pH=7.4) at room temperature for 14 days with daily solution refreshment; ②Partially demineralized dentin ( n=15), specimens were treated with 37% phosphoric acid gel (Ultra-Etch, Ultradent) for 15 seconds followed by thorough rinsing with deionized water. Three remineralization groups were established for demineralized dentin treatment: ①Control group, 50% ethanol solution; ②ACMP group, 50% ethanol solution containing amorphous magnesium calcium phosphate (ACMP); ③PAMAM-COOH/ACMP group, 50% ethanol solution incorporating carboxylated polyamidoamine dendrimer-modified ACMP (PAMAM-COOH/ACMP). The chemical composition of remineralization solutions was analyzed by Fourier-transform infrared spectrum (FTIR). The morphology and particle size distribution of nanoparticles were characterized using transmission electron microscope (TEM). The fully demineralized dentin specimens were treated with three different remineralization solutions (37 ℃ for 7 days) respectively. The mineralization of the dentin collagen fibers surface was observed using scanning electron microscope (SEM) and the distribution of minerals inside and outside the collagen fibers was examined by using TEM. The partially demineralized dentin specimens were treated with fluorescence-labeled remineralization solutions (37 ℃ for 7 days) respectively, followed by analysis using confocal laser scanning microscopy (CLSM) to quantitatively evaluate the penetration depth of the mineralization agents. Results:FTIR analysis confirmed the presence of characteristic absorption peaks corresponding to phosphate (PO 43-) groups, carbon-nitrogen bonds, and amide linkages in the PAMAM-COOH/ACMP nanocomposite. TEM observed that the PAMAM-COOH/ACMP nanoparticles exhibited an average particle size of (36.85±8.02) nm in an amorphous state. SEM observation indicates continuous mineral deposition on dentin collagen fibers in the PAMAM-COOH/ACMP group, while no mineral deposition in the control group and only minimal deposition in the ACMP group. TEM showed no mineral deposition inside or outside the collagen fibers in the control group, only external mineral deposition in the ACMP group, and high-density mineral deposition both inside and outside the fibers in the PAMAM-COOH/ACMP group. CLSM analysis revealed a statistically significant difference ( P<0.05) in the depth of mineralized substances entering dentin tubules between ACMP group and PAMAM-COOH/ACMP group. Conclusions:The remineralization system of 50% ethanol solution incorporating PAMAM-COOH/ACMP successfully achieved the internal and external mineralization of demineralized dentin collagen fibers.

Ocular accommodation refers to the process by which the ciliary muscle creates a clear image of the object in the retina by changing the refractive power of the lens. When the accommodation ability of the eye is insufficient, the imaging focus falls on the region behind the retina and hyperopic defocus is easily formed, resulting in axial growth and leading to the development of myopia, and it is found that most myopic patients usually have some accommodation dysfunction. Myopia has become a public health problem in China, and the prevalence of adolescents has increased dramatically. How to prevent and stop the occurrence and development of myopia is a major challenge. Previous studies have found that ocular accommodation dysfunction is associated with the occurrence and development of myopia, and the measurement of parameters related to accommodation function has certain guiding significance for the prevention and control of myopia. The purpose of this paper is to review the correlation between myopia and ocular accommodation function, with a view to providing new ideas for the prevention, control and treatment of myopia.

Background Phakic posterior chamber implantable contact lens (PPC-ICL) or phakic posterior chamber Toric implantable contact lens (PPC-TICL) implantation is an effective way for the correction of high myopia or high myopia with astigmia,but it often has residual myopic power.Excimer laser-assisted subepithelial keratectomy (LASEK) can correct the residual myopia following PPC-ICL or PPC-TICL,but its effectiveness and safety deserve attention.Objective This study was to analyze the clinical effectiveness and safety of LASEK for residual myopia after PPC-ICL implantation for extreme high myopia.Methods A prospective cases-observational study was performed,and written informed consent was obtained from each patient before any surgery.Fourteen eyes of 9 patients with residual myopia following PPC-ICL or PPC-TICL for the eyes with spherical equivalent refraction of ≥-20.00 D were collected in the Affiliated Hospital of Guizhou Medical University from July 2010 to March 2015,including PPCICL implantation in 8 eyes and PPC-TICL implantation in 6 eyes.LASEK were performed on the eyes to correct the residual myopic power.Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),haze,the distance of intraocular lens to lens,corneal thickness,corneal topography,corneal endothelial cell counting,intraocular pressure (IOP) and fundus were examined and compared before and after surgery.The effectiveness and safety of the surgery were evaluated.Results The operation was smooth and no complication was found after surgery in all of the eyes.The UCVA and BCVA were significantly different in the eyes among before surgery,6 months after PPC-ICL implantation and 12 months after LASEK (F =31.360,1.778;both at P＜0.05),and the UCVA after LASEK was higher than BCVA before LASEK.The refractive powers were (-22.27-±4.29),(-3.75±2.25) and (-0.42±0.63) D before surgery,6 months after PPC-ICL implantation and 12 months after LASEK,showing a significant difference among them (F=46.370,P＜0.05),and the refractive power was considerably lower after LASEK than that before surgery and after PPC-ICL implantation (both at P＜0.05).No significant difference was found in IOP or corneal endothelial cell counting in operated eyes among before surgery,6 months after PPC-ICL implantation and 12 months after LASEK (F=1.663,1.055;both at P＞0.05).The distance of intraocular lens to lens was (0.69±0.26)mm in the eyes after LASEK and (0.71 ±0.29)mm in the eyes after PPC-ICL implantation,with no significant difference between them (t =0.192,P＞0.05).Conclusions PPC-ICL or PPC-TICL implantation for the correction extreme high myopia often remains a certain degree of myopia,and LASEK for the correction of residual refractive power is safe and effective.