Treatment of donor site wounds using facial skin remaining in the scar area.

Reconstruction of cheek skin defects is surgically challenging. We evaluated the outcomes of using cheek skin remaining in the scar area for treating donor site wounds following the repair of cheek skin defects using full-thickness skin. We conducted a retrospective case series study that included 12 patients with a scar of the cheek. The patients included seven females and five males. The donor site was treated using the cheek skin remaining in the scar area following repair of the cheek skin defect with a full-thickness skin graft from the inner side of the upper arm. Minor flap necrosis of the full-thickness skin graft in the cheek developed in one patient. The postoperative esthetic results were excellent and satisfactory in 11 and 1 patient, respectively. Patients were followed up for 18-32 months; no lagophthalmos or ectropion was noted. However, there were two cases of hyperpigmentation in cheek grafts, and two of graft hypertrophy in the arm. The facial skin remaining in the scar area can be used to treat donor site wounds following a full-thickness skin graft from the inner side of the upper arm to repair a large cheek skin defect.

Vermilionectomy followed by reconstruction of the vermilion mucosa using allograft dermal matrix in patients with actinic cheilitis of the lower lip.

BACKGROUND: When treating actinic cheilitis (AC), it is essential to minimize the risk of malignant transformation (MT) and maintain lip functionality and cosmesis. AIMS: We evaluated the outcomes of vermilionectomy followed by reconstruction of the vermilion mucosa using allograft dermal matrix (ADM) in patients with AC of the lower lip. MATERIALS AND METHODS: We evaluated eight patients with lower lip AC who underwent vermilion mucosa reconstruction using ADM after vermilionectomy. We enrolled five males and three females ranging in age from 55 to 70 years (mean, 62.1 years). The ADM ranged in area from 1.3 × 5.0 to 1.7 × 5.8 cm (median, 1.6 × 5.5 cm). All patients were followed up for at least 3 months postoperatively by a panel of three surgeons who assessed the esthetic results, and orbicularis oris and speech functions. RESULTS: All patients underwent successful reconstruction of the vermilion mucosa using ADM after vermilionectomy, without complications. The postoperative esthetic results, and the orbicularis oris and speech functions, were satisfactory to excellent in all patients. Patients were followed up for 18-38 months (median, 26.1 months). No MT or recurrence was noted. CONCLUSIONS: Vermilionectomy followed by reconstruction of the vermilion mucosa with ADM is safe and feasible for AC patients.

Thread shape affects the stress distribution of torque force on miniscrews: a finite element analysis.

This study aimed to investigate the effect of miniscrews thread shape on the stress distribution receiving a torque load. Seven thread shapes (S,V1,V2,B1,B2,R1,R2) models were constructed and a 6 Nmm-torque load was applied. The order of maximum equivalent stress (EQV) value was V1 > V2 > B1 > R1 > R2 > B2 > S. The order of maximum displacement of miniscrew (Max DM) value was S > B2 > R1 = V1 > B1 > V2 > R2. Model R2 may be the most appropriate thread shape affording a torque force.

Finite Element Analysis of Bone Stress around Micro-Implants of Different Diameters and Lengths with Application of a Single or Composite Torque Force.

BACKGROUND: Stress on the bone surrounding dental micro-implants affects implant success. PURPOSE: To compare the stress on the bone surrounding a micro-implant after application of a single force (SF) of 200 g or a composite force (CF) of 200 g and 6 N.mm torque. MATERIALS AND METHODS: Finite element models were developed for micro-implant diameters of 1.2, 1.6, and 2.0 mm, and lengths of 6, 8, 10, and 12 mm and either a SF or CF was applied. The maximum equivalent stress (Max EQS) of the bone surrounding the micro-implant was determined, and the relationships among type of force, diameter, and length were evaluated. RESULTS: The Max EQS of the CF exceeded that of the SF (P< 0.05). The effect of force on stress was related to implant diameter, but not to implant length. The larger CF led to greater instability of the micro-implant and the effect was most pronounced at an implant diameter of 1.2 mm. The use of implant diameters of 1.6 mm and 2.0 mm produced no significant difference in implant stability when either a CF or SF was applied. CONCLUSION: When considering the use of an implant to perform three-dimensional control on the teeth, the implant diameter chosen should be > 1.2 mm.

Effect of heating palladium-silver alloys on ceramic bond strength.

STATEMENT OF PROBLEM: The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation. PURPOSE: The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements. MATERIAL AND METHODS: Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens. RESULTS: The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (P<.001). Heating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, P<.001). Heating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules. CONCLUSIONS: Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys.

[Influence of the diameter and length of the mini-implant on the primary stability after loading with composite forces].

OBJECTIVE: To investigate the influence of the diameter and length of the mini-implant on the primary stability after loading with composite forces (CF) which contained torque and horizontal forces (HF). METHODS: Ninety-six finite element models were established by the combination of mini-implant and bone, diameters (1.2 mm, 1.6 mm, 2.0 mm) and length (6 mm, 8 mm, 10 mm, 12 mm). There were 12 sizes, each size corresponded with 8 models. Group HF (each size n = 4) was loaded with 1.96 N horizontal force and Group CF (each size n = 4) was loaded with composite force which contained 6 N·mm torque and 1.96 N horizontal force. The maximum displacement of mini-implant with different force directions, implant diameters and lengths were evaluated. RESULTS: The effect of force direction on the displacement related to diameter of mini-implant. The maximum displacement under load with HF respectively was changed with the changing of diameter[1.2 mm: (7.71 ± 0.49) µm; 1.6 mm: (3.94 ± 0.31) µm; 2.0 mm: (2.32 ± 0.43) µm], which were smaller than the maximum displacement of Group CF [1.2 mm: (9.22 ± 0.63) µm; 1.6 mm: (4.62 ± 0.52) µm; 2.0 mm: (2.69 ± 0.49) µm] (P < 0.05). When diameter was 1.2 mm, the difference of the maximum displacement [(1.61 ± 0.22) µm] between Group HF and CF was more obvious than that when the diameter was 1.6 mm or 2.0 mm [(0.64 ± 0.12), (0.49 ± 0.06) µm] (P < 0.05). CONCLUSIONS: The composite force had unfavorable effect on the primary stability of the mini-implant. The diameter of the mini-implant had better be larger than 1.2 mm when the composite forces were applied.

Expression of Cyr61 in primary salivary adenoid cystic carcinoma and its relation to Ki-67 and prognosis.

Cysteine-rich protein 61 (Cyr61) selectively binds heparin and insulin-like growth factors and mediates a variety of biological actions, including cell adhesion, differentiation, proliferation, migration, angiogenesis, and tumorigenesis. Cyr61 is also a prognostic factor for tumor progression and survival of individuals with various types of tumors. This study investigated the relationship between the expression level of Cyr61 and clinicopathological features, as well as the prognostic significance of Cyr61 expression in human salivary adenoid cystic carcinoma (SACC). The expression of Cyr61 and Ki-67, a cell-proliferation marker, was examined immunohistochemically in paraffin embedded tissue specimens from 60 SACC patients who underwent radical surgery between 1995 and 2004. A chi-square test was used to investigate the relationship between Cyr61 and Ki-67 expression and clinicopathological features. Survival analysis was performed to determine the prognostic significance of Cyr61 expression. Cyr61 expression was observed in 39 cases (39/60, 65%) of SACC, and Cyr61 expression was positively correlated with Ki-67 expression (P=0.002). A high expression of Cyr61 was significantly associated with solid subtype, perineural invasion, vascular invasion or cancer embolus, advanced stage, recurrence, and metastasis (P<0.05). The survival rate of patients with high expression of Cyr61 or Ki67 was significantly lower than that of patients with low expression. Multivariate Cox's proportional hazards analysis showed that vascular invasion, TNM stage, recurrence, distant metastasis, Ki-67 expression, and Cyr61 expression were independent prognostic factors of overall survival (P<0.05). Cyr61 expression is significantly correlated with Ki-67 expression and may have potential value in screening high-risk cases for recurrence and metastasis, as well as identifying poor prognosis in SACC patients.