[Four-year follow-up study of onlay and occlusal veneer restorations on posterior teeth]

OBJECTIVE

To investigate the survival rate and clinical failure reasons of onlay and occlusal veneer restorations retrospectively, and to put forward valuable suggestions for the selection of clinical indications.

METHODS

A total of 102 patients and 124 teeth treated by one of the authors from 2016 to 2019 were subjected to CAD/CAM lithium silicate reinforced glass-ceramic onlay or veneer restorations of premolars and molars, including 43 teeth with pulp vitality, 81 endodontic treated teeth, and occlusal thickness of restoration was 1.5 mm. After four years of restoration, retrospective surveys were conducted to record the survival rate of restorations, the causes of restoration failure, and patient satisfaction rates, and the survival rate of restorations between vital teeth and endodontic treated teeth and among restored teeth was statistically analyzed by Chi-square test.

RESULTS

The survival rates of restorations on vital teeth and endodontic treated teeth were 95.5% and 90.0%, respectively, the average survival rate was 90.2%. The survival rates of vital teeth were higher than those of endodontic treated teeth without statistical difference. There was also no statistically significant difference among the tooth locations. The causes of failure included the cracking of the restoration, the loss of the restoration, the fracture of the abutment teeth, secondary caries below the adjacent contact point, and food impaction caused by the loosening of the adjacent contact point. The overall patient satisfaction rate was 91.5%.

CONCLUSION

The 4-year survival rate of glass-ceramic onlays and occlusal veneers is lower than that of the full crown restoration, and there are more complications than that of the single-crown restorations. The design of the restoration should be carefully selected based on the vitality of the abutment tooth and the remaining amount of tooth tissue. When there is too little tooth structure left, a post and crown should be selected for restoration. Adequate strength and thickness of the restoration should be ensured to prevent food impaction. Due to the small amount of abutment tooth preparation, it has the advantages of less stimulation of the pulp and periodontal tissue, and can be recommended as a trial restoration.

[Risk Factors of Rapidly Progressive Interstitial Lung Disease in Patients With Anti-Melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis]

Objective

To investigate the conditions of patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis combined with rapidly progressive interstitial lung disease (RPILD), and to analyze the risk factors.

Methods

A total of 145 patients diagnosed with anti-MDA5 antibody-positive dermatomyositis at West China Hospital, Sichuan University between January 2018 and September 2021 were selected, and their general and clinical data were collected. The patients were divided into two groups, a RPILD group of patients with comorbid RPILD and a non-RPILD group of those who did not have comorbid RPILD. Factors that might affect whether patients with anti-MDA5 antibody-positive dermatomyositis also had comorbid RPILD were screened out and binary logistic regression analysis was performed.

Results

Among the 145 patients with anti-MDA5 antibody-positive dermatomyositis, 32 (22.07%) patients had comorbid RPILD, while the remaining 113 (77.93%) did not have comorbid RPILD. Binary logistic regression analysis showed that lactate dehydrogenase≥370 IU/L (compared with <370 IU/L, OR=4.066, 95% CI: 1.616-10.230) and carcinoembryo antigen≥5 ng/mL (compared with <5 ng/mL, OR=6.070, 95% CI: 2.013-18.303) were risk factors for comorbid RPILD in patients with anti-MDA5 antibody-positive dermatomyositis ( β>0, OR>1, P<0.05).

Conclusion

It is recommended that close attention be given to changes in high-resolution chest CT and pulmonary functions in patients with lactate dehydrogenase≥370 IU/L and carcinoembryo antigen≥5 ng/mL. If rapid progression of lung disease is detected, it is necessary to strengthen the treatment of the lung disease, thereby improving the prognosis of patients.

[Early constant observation of the effect of deferoxamine mesylate on improvement of vascularized bone regeneration in SD rat skull critical size defect model]

OBJECTIVE

To investigate the effect of local administration of deferoxamine mesylate (DFO) on vascularization and osteogenesis and its ability to maintain the activity of hypoxia inducible factor-1α (HIF-1α), by constantly observing early changes of vessel-like structures and bone tissues during bone defects healing.

METHODS

Skull critical bone defect models were constructed on a total of thirty male SD rats (6-8 weeks old). The rats were randomly divided into experimental group (DFO group) or control group (normal saline group). 300 μL 200 μmol/L DFO solution or normal saline was locally injected on the 4th day after the defect was made. On the 5th, 7th, 10th, 14th, and 28th days after surgery, three rats in each group were sacrificed respectively. HE staining and Masson staining were performed to observe new bone formation and mineralization. HIF-1α immunohistochemistry staining was performed to examine relative expression of protein. Qualitative analysis and comparation were performed by t-tests on relative expression of HIF-1α, numbers of blood vessels and percentages of mineralization tissues of new bone areas.

RESULTS

On the 5th, 7th, 10th, 14th and 28th days after surgery, the average numbers of blood vessels were 30.40±12.15, 62.00±17.87, 73.43±15.63, 40.00±7.84, 48.71±11.64 in the DFO group, and 18.75±6.63, 19.13±2.80, 51.35±16.21, 27.18±7.32, 30.88±13.43 in the control group. The number of blood vessels in the DFO group was significantly higher than that of the control group at each time point (P < 0.05). The mass of new bone in the DFO group was higher than that in the control group on the 14th and 28th days after surgery. The percentage of mineralization tissues of new bone area on the 14th and 28th days after injection were (27.73±5.93)% and (46.53±3.66)% in the DFO group, and (11.99±2.02)% and (31.98±4.22)% in the control group. The percentage of mineralization tissues in the DFO group was significantly higher than that of the control group at each time point (P < 0.001). The relative expression of HIF-1α in the DFO group compared with the control group was 2.86±0.48, 1.32±0.26, 1.32±0.32, 1.28±0.38 and 1.05±0.34 on the 5th, 7th, 10th, 14th and 28th days, with significant expression difference on the 5th day (P < 0.01).

CONCLUSION

Use of DFO in bone defects promotes vascularization and osteogenesis in the defect area, and maintains the protein activity of HIF-1α temporarily.

[Study of masking ability of laminate veneers for discolored teeth]

OBJECTIVE

To select the most effective method among different masking treatments, such as different thickness and transparence, tissue surface's opaque coating, and opaque resin cement to restore discolored teeth esthetically by porcelain veneer.

METHODS

Four extracted intact maxillary central incisors were prepared for porcelain veneer restoration and each three heat pressed porcelain veneers from three thicknesses (0.8 mm, 1.0 mm, 1.2 mm) and two transparency(high transparence, HT and low transparence, LT))in Vita shade A2 were fabricated for each tooth, in total of 72 pieces. The surfaces of three prepared teeth were then painted to mimic situations of severe dental fluorosis, severe tetracycline teeth, and necrotic teeth. Each of the veneers was temporarily cemented to the corresponding tooth surface using try-in cements with three different colors (transparent, opaque, and yellow), then used the shade guide (3D master) and electronic colorimeter (easy shade) to record the shade of each porcelain veneer through hue, lightness, and chroma reading. After that, high-transparence porcelain veneers in thickness of 0.8 mm was fused with a layer of opaque porcelain in tissue surface, and were shade matched again after cementation. Statistic treatments were performed to analyze the difference in each masking method.

RESULTS

For each 0.2 mm increase in the veneer thickness of porcelain, the average lightness was reduced by 1 unit, while the chroma was not changed which was independent of the type of the resin cements. When the thickness of the porcelain veneer was decreased to 0.8 mm, the opacity effect was not remarkable even if a low-transparence porcelain veneer was used. Transparent and yellow resin cements had poor opaque performance, while opaque resin cement could reduce the lightness by 2 units and the chroma was also reduced. The opaque layer of the tissue surface could be applied uniformly, and the lightness and chroma could be reduced to Vita 2M1 to 2M1.5 levels regardless of the color of resin cements, which suggested a stable opacity effect for different discolored teeth in this study.

CONCLUSION

For porcelain veneer restoration of discolored teeth, thickened veneers are the most effective means to display a natural transmittance and color. Tissue surface's opacity coatings and opaque resin cements can also be used to reduce grayscale and increase lightness.

[Study of masking ability of laminate veneers for discolored teeth]

OBJECTIVE

To select the most effective method among different masking treatments, such as different thickness and transparence, tissue surface's opaque coating, and opaque resin cement to restore discolored teeth esthetically by porcelain veneer.

METHODS

Four extracted intact maxillary central incisors were prepared for porcelain veneer restoration and each three heat pressed porcelain veneers from three thicknesses (0.8 mm, 1.0 mm, 1.2 mm) and two transparency(high transparence, HT and low transparence, LT))in Vita shade A2 were fabricated for each tooth, in total of 72 pieces. The surfaces of three prepared teeth were then painted to mimic situations of severe dental fluorosis, severe tetracycline teeth, and necrotic teeth. Each of the veneers was temporarily cemented to the corresponding tooth surface using try-in cements with three different colors (transparent, opaque, and yellow), then used the shade guide (3D master) and electronic colorimeter (easy shade) to record the shade of each porcelain veneer through hue, lightness, and chroma reading. After that, high-transparence porcelain veneers in thickness of 0.8 mm was fused with a layer of opaque porcelain in tissue surface, and were shade matched again after cementation. Statistic treatments were performed to analyze the difference in each masking method.

RESULTS

For each 0.2 mm increase in the veneer thickness of porcelain, the average lightness was reduced by 1 unit, while the chroma was not changed which was independent of the type of the resin cements. When the thickness of the porcelain veneer was decreased to 0.8 mm, the opacity effect was not remarkable even if a low-transparence porcelain veneer was used. Transparent and yellow resin cements had poor opaque performance, while opaque resin cement could reduce the lightness by 2 units and the chroma was also reduced. The opaque layer of the tissue surface could be applied uniformly, and the lightness and chroma could be reduced to Vita 2M1 to 2M1.5 levels regardless of the color of resin cements, which suggested a stable opacity effect for different discolored teeth in this study.

CONCLUSION

For porcelain veneer restoration of discolored teeth, thickened veneers are the most effective means to display a natural transmittance and color. Tissue surface's opacity coatings and opaque resin cements can also be used to reduce grayscale and increase lightness.

[Preparation of aspirin sustained-release microsphere and its in vitro releasing property]

OBJECTIVE

It has been proven that acetylsalicylic acid (aspirin), as a kind of classical non-steroidal anti-inflammatory drug, not only has the effect of anti-inflammatory, but also has the function of immunity regulation and mineralization. However, it needs further investigation to study how to delay release of aspirin for a long time and enable to promote bone regeneration. Herein, we demonstrated that the longterm delayed release pattern of aspirin through the construction of microsphere scaffolds is promising to achieve the excellent bone regeneration.

METHODS

Here we synthesized three kinds of scaffolds as follows: (1) aspirin loaded calcium silicate (CaSiO₃) microsphere (CaSiO₃-aspirin) via simple immersion; (2) aspirin loaded polylactic-co-glycolic acid (PLGA) microsphere (PLGA-aspirin) via oil/water (O/W) emulsion; (3) aspirin loaded PLGA-CaSiO₃ scaffold (PLGA-CaSiO₃-aspirin) via O/W emulsion, optimal morphology and structure of PLGA-CaSiO₃-aspirin scaffold was acquired through modulating the ratio between PLGA and CaSiO₃. Furthermore, spectrophotometer was used to monitor the concentration of the extract of the three scaffolds for different releasing time, including 1, 2, 4, 6, 9, 13, 17, 21, 24, 30, 36, and 45 days, aspirin loading efficiency and its accumulation releasing curves were both achieved according to the concentration of aspirin. Their sustained release effects of aspirin were evaluated eventually.

RESULTS

Environmental scanning electron microscope (ESEM) results showed that the surface structure of the three kinds of scaffolds were smooth and had uniform size distribution. In addition, a small amount of PLGA-aspirin microspheres occurred to aggregation, while a small amount of CaSiO₃-aspirin microspheres were broken. Moreover, the PLGA-aspirin microspheres in the PLGA-CaSiO₃-aspirin scaffolds were uniformly adhered to the surface of CaSiO₃ microspheres. The aspirin loadings of CaSiO₃-aspirin, PLGA-aspirin, and PLGA-CaSiO₃-aspirin were (1.06±0.04)%, (7.05±0.06)%, and (6.75±0.18)%, respectively. In addition, their corresponding time for releasing 95% of aspirin was 3, 24, and 36 days, respectively. The releasing time of PLGA-CaSiO₃-aspirin was longer than that of the others and the releasing rate was more stable.

CONCLUSION

The microsphere scaffold of PLGA-CaSiO₃-aspirin composites has excellent delayedrelease effect on aspirin, which is promising for using as osteogenic materials.