BACKGROUND The conventional implant approach involves flap elevation,which may result in increased soft tissue and bone loss and postoperative morbidity.The flapless surgical technique,aided by three-dimensional medic...BACKGROUND The conventional implant approach involves flap elevation,which may result in increased soft tissue and bone loss and postoperative morbidity.The flapless surgical technique,aided by three-dimensional medical imaging equipment,is regarded as a possible alternative to the conventional approach to alleviate the above issues.Several studies have been performed regarding the role of flapless implant surgery.However,the results are inconsistent and there is no robust synthesis of long-term evidence to better inform surgeons regarding which type of surgical technique is more beneficial to the long-term prognosis of patients in need of implant insertion.AIM To compare the long-term clinical performance after flapless implant surgery to that after the conventional approach with flap elevation.METHODS PubMed,EMBASE,Cochrane Central Register of Controlled Trials,and grey literature databases were searched from inception to 23 September 2019.Randomised controlled trials(RCTs)and cohort studies comparing the long-term clinical performance after flapless implant surgery to that after the conventional approach over a follow-up of three years or more were included.Meta-analyses were conducted to estimate the odds ratios(ORs)or mean differences(MDs)and their 95%confidence intervals(CIs)between the long-term implant survival rate,marginal bone loss,and complication rate of the flapless and conventional groups.Subgroup analyses were carried out to account for the possible effects of the guided or free-hand method during flapless surgery.RESULTS Ten articles,including four RCTs and six cohort studies,satisfied the eligibility criteria and nine of them were included in the meta-analysis.There was no significant difference between the long-term implant survival rate[OR=1.30,95%CI(0.37,4.54),P=0.68],marginal bone loss[MD=0.01,95%CI(-0.42,0.44),P=0.97],and complication rate[OR=1.44,95%CI(0.77,2.68),P=0.25]after flapless implant surgery and the conventional approach.Moreover,subgroup analyses revealed that there was no statistically significant difference between the implant survival rate[guided:OR=1.52,95%CI(0.19,12.35),P=0.70];free-hand:n=1,could not be estimated,marginal bone loss[guided:MD=0.22,95%CI(-0.14,0.59),P=0.23;free-hand:MD=-0.27,95%CI(-1.10,0.57),P=0.53],or complication rate[guided:OR=1.16,95%CI(0.52,2.63),P=0.71;free-hand:OR=1.75,95%CI(0.66,4.63),P=0.26]in the flapless and conventional groups either with use of the surgical guide or by the free-hand method.CONCLUSION The flapless surgery and conventional approach had comparable clinical performance over three years or more.The guided or free-hand technique does not significantly affect the long-term outcomes of flapless surgery.展开更多
Corresponding to the atmospheric transmission windows of the electromagnetic spectrum in the low terahertz range,the mode coupling and dispersion characteristics of two helically corrugated waveguides(HCW)in the frequ...Corresponding to the atmospheric transmission windows of the electromagnetic spectrum in the low terahertz range,the mode coupling and dispersion characteristics of two helically corrugated waveguides(HCW)in the frequency ranges of 90 GHz-100 GHz and 260 GHz-265 GHz are studied.Through analytic calculations and numerical simulations,dispersion curves and structural parameters of the two frequency ranges waveguides are obtained.A novel method was proposed to obtain the dispersion of the HCW from the eigenwave solution using a periodic boundary condition.The HCW in a frequency range of 90 GHz-100 GHz was fabricated and its dispersion performance was measured.By comparing the measured results with the theoretical and the simulated results,the validity of the analytical and simulation method is verified.Limited to our machining capability,the dispersion of the 260 GHz-265 GHz HCW was only simulated and calculated and it was found that the results agree well with each other.展开更多
BACKGROUND The pontic design of fixed dental prostheses(FDPs)is strongly associated with the phonetic function,and the phonetic function of anterior FDPs with different pontic designs remains understudied.AIM To inves...BACKGROUND The pontic design of fixed dental prostheses(FDPs)is strongly associated with the phonetic function,and the phonetic function of anterior FDPs with different pontic designs remains understudied.AIM To investigate the immediate and short-term influence of pontic design of anterior FDPs on Chinese speech in a clinical case using objective acoustic analysis.METHODS Two FDPs with two types of pontic design(saddle pontic and modified ridge lap pontic)were fabricated for one patient with maxillary anterior teeth missing.The acoustic analysis of patient’s articulation was conducted immediately after wearing the FDPs and 1 wk after wearing these FDPs.RESULTS The effect of FDP on Chinese vowels(/a/,/o/,/e/,/i/,/u/,and/ü/)was insignificant,because the recovery of vowel distortion occurred within 1 wk for both FDPs.Three(/f/,/s/,and/sh/)of eight Chinese fricative consonants were found to have obvious distortions,and the/s/sound distortion last for more than 1 wk for the patient wearing FDP with modified ridge lap pontic design.CONCLUSION The influence of anterior FDP on articulation of Chinese vowels is insignificant,while the articulation of Chinese fricative consonants is more susceptible.When fabricating anterior FDPs for patients with speech related professions,saddle pontic design can be an alternative option compared with modified ridge lap pontic design.展开更多
基金the Graduate Student's Research and Innovation Fund of Sichuan University,No.2018YJSY108the China Postdoctoral Science Foundation Funded Project,No.2018M640931+1 种基金the Science and Technology Key Research and Development Program of Sichuan Province,No.2019YFS0142the National Natural Science Foundation of China,No.81901060.
文摘BACKGROUND The conventional implant approach involves flap elevation,which may result in increased soft tissue and bone loss and postoperative morbidity.The flapless surgical technique,aided by three-dimensional medical imaging equipment,is regarded as a possible alternative to the conventional approach to alleviate the above issues.Several studies have been performed regarding the role of flapless implant surgery.However,the results are inconsistent and there is no robust synthesis of long-term evidence to better inform surgeons regarding which type of surgical technique is more beneficial to the long-term prognosis of patients in need of implant insertion.AIM To compare the long-term clinical performance after flapless implant surgery to that after the conventional approach with flap elevation.METHODS PubMed,EMBASE,Cochrane Central Register of Controlled Trials,and grey literature databases were searched from inception to 23 September 2019.Randomised controlled trials(RCTs)and cohort studies comparing the long-term clinical performance after flapless implant surgery to that after the conventional approach over a follow-up of three years or more were included.Meta-analyses were conducted to estimate the odds ratios(ORs)or mean differences(MDs)and their 95%confidence intervals(CIs)between the long-term implant survival rate,marginal bone loss,and complication rate of the flapless and conventional groups.Subgroup analyses were carried out to account for the possible effects of the guided or free-hand method during flapless surgery.RESULTS Ten articles,including four RCTs and six cohort studies,satisfied the eligibility criteria and nine of them were included in the meta-analysis.There was no significant difference between the long-term implant survival rate[OR=1.30,95%CI(0.37,4.54),P=0.68],marginal bone loss[MD=0.01,95%CI(-0.42,0.44),P=0.97],and complication rate[OR=1.44,95%CI(0.77,2.68),P=0.25]after flapless implant surgery and the conventional approach.Moreover,subgroup analyses revealed that there was no statistically significant difference between the implant survival rate[guided:OR=1.52,95%CI(0.19,12.35),P=0.70];free-hand:n=1,could not be estimated,marginal bone loss[guided:MD=0.22,95%CI(-0.14,0.59),P=0.23;free-hand:MD=-0.27,95%CI(-1.10,0.57),P=0.53],or complication rate[guided:OR=1.16,95%CI(0.52,2.63),P=0.71;free-hand:OR=1.75,95%CI(0.66,4.63),P=0.26]in the flapless and conventional groups either with use of the surgical guide or by the free-hand method.CONCLUSION The flapless surgery and conventional approach had comparable clinical performance over three years or more.The guided or free-hand technique does not significantly affect the long-term outcomes of flapless surgery.
文摘Corresponding to the atmospheric transmission windows of the electromagnetic spectrum in the low terahertz range,the mode coupling and dispersion characteristics of two helically corrugated waveguides(HCW)in the frequency ranges of 90 GHz-100 GHz and 260 GHz-265 GHz are studied.Through analytic calculations and numerical simulations,dispersion curves and structural parameters of the two frequency ranges waveguides are obtained.A novel method was proposed to obtain the dispersion of the HCW from the eigenwave solution using a periodic boundary condition.The HCW in a frequency range of 90 GHz-100 GHz was fabricated and its dispersion performance was measured.By comparing the measured results with the theoretical and the simulated results,the validity of the analytical and simulation method is verified.Limited to our machining capability,the dispersion of the 260 GHz-265 GHz HCW was only simulated and calculated and it was found that the results agree well with each other.
基金the National Natural Science Foundation of China,No.81901060the China Postdoctoral Science Foundation Funded Project,No.2018M640931the Science and Technology Key Research and Development Program of Sichuan Province,No.2019YFS0142.
文摘BACKGROUND The pontic design of fixed dental prostheses(FDPs)is strongly associated with the phonetic function,and the phonetic function of anterior FDPs with different pontic designs remains understudied.AIM To investigate the immediate and short-term influence of pontic design of anterior FDPs on Chinese speech in a clinical case using objective acoustic analysis.METHODS Two FDPs with two types of pontic design(saddle pontic and modified ridge lap pontic)were fabricated for one patient with maxillary anterior teeth missing.The acoustic analysis of patient’s articulation was conducted immediately after wearing the FDPs and 1 wk after wearing these FDPs.RESULTS The effect of FDP on Chinese vowels(/a/,/o/,/e/,/i/,/u/,and/ü/)was insignificant,because the recovery of vowel distortion occurred within 1 wk for both FDPs.Three(/f/,/s/,and/sh/)of eight Chinese fricative consonants were found to have obvious distortions,and the/s/sound distortion last for more than 1 wk for the patient wearing FDP with modified ridge lap pontic design.CONCLUSION The influence of anterior FDP on articulation of Chinese vowels is insignificant,while the articulation of Chinese fricative consonants is more susceptible.When fabricating anterior FDPs for patients with speech related professions,saddle pontic design can be an alternative option compared with modified ridge lap pontic design.
