A preliminary study to find out maximum occlusal bite force in Indian individuals.

Purpose: This preliminary hospital based study was designed to measure the mean maximum bite force (MMBF) in healthy Indian individuals. An attempt was made to correlate MMBF with body mass index (BMI) and some of the anthropometric features. Methodology: A total of 358 healthy subjects in the age range of 18-47 years (mean age = 26.66 ± 6.83) were selected following the selection criteria. Demographic details along with general physical and facial parameters such as height, weight, facial form, facial profile, arch form, and palatal contour were recorded in a predesigned proforma. The maximum bite force was recorded on both (right and left) sides using a specially designed piezoelectric transducer based device. Results: The MMBF in Indian individuals was found to be 372.39 ± 175.93 Newton (N). Males had significantly higher (P = 0.000) MMBF (448.47 ± 191.82 N) as compared to females (296.31 ± 116.79 N). Facial form (P = 0.001) and palatal contour (P = 0.000) showed a significant relationship with MMBF. Subjects having square facial form (421.34 ± 187.32 N) showed significantly higher MMBF as compared to other facial forms, that is, square tapered (358.86 ± 143.56 N; P = 0.038), ovoid (338.40 ± 163.02 N; P = 0.000) and tapered (349.22 ± 184.82 N; P = 0.028). Subjects with flat palatal contour showed significantly higher MMBF when compared to high (P = 0.002) and medium palatal (P = 0.002) contour. Though facial profile was not significantly related to MMBF, it was significantly higher in subjects having concave facial profile when compared to convex (P = 0.045) and straight (P = 0.039) facial profile. BMI and arch form showed no significant relationship with MMBF. Conclusion: The MMBF is found to be affected by gender and some of the anthropometric features like facial form and palatal contour.

Design of phacoemulsification handpiece and ANSYS finite element optimization analysis / 国际生物医学工程杂志

Objective To design phacoemulsification handpiece with small size and high amplitude amplification coefficient.Methods By introducing the electro-mechanical vibration characteristics of piezoelectric transducer and ultrasonic horn,and adopting the equivalent circuit method and analytical method,respectively,the size of the ultrasonic horn,quarter wavelength piezoelectric transducer and ultrasonic horn were designed.Then,modal and harmonic analysis in finite element analysis software ANSYS11.0 were used to simulate the handpiece,and to optimize the size of the handpiece after adding on needle.Results The results indicated that the longitudinal vibration frequency and amplification coefficient were very close to theoretical design.The errors were 1.4％ and 5.8％,respectively.When piezoelectric ceramics were loaded with 300 V sinusoidal voltage,the displacement amplitude at the end of the needle reached 125.5 μm,which could meet the phacoemulsification surgery needs.Conclusion This design greatly reduced the size of the handpiece,and obtained high amplitude amplification coefficient.The simulation results sufficiently validated the theoretical design.