Heng-li Huang - Academia.edu (original) (raw)

Papers by Heng-li Huang

International Journal of Environmental Research and Public Health

Dental implants are among the most common treatments for missing teeth. The thickness of the cres... more Dental implants are among the most common treatments for missing teeth. The thickness of the crestal cortical bone at the potential dental implant site is a critical factor affecting the success rate of dental implant surgery. However, previous studies have predominantly focused on female patients, who are at a high risk of osteoporosis, for the discussion of bone quality and quantity at the dental implant site. This study aimed to investigate the effect of male patients’ age on the crestal cortical bone of the jaw at the dental implant site by using dental cone-beam computed tomography (CBCT). This study performed dental CBCT on 84 male patients of various ages to obtain tomograms of 288 dental implant sites at the jawbone (41 sites in the anterior maxilla, 95 in the posterior maxilla, 59 in the anterior mandible, and 93 in the posterior mandible) for measuring the cortical bone thickness. A one-way analysis of variance and Scheffe’s test were performed on the measurement results t...

Diagnostics

Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably... more Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably affected by host bone quality and quantity, which is often assessed prior to surgery through dental cone-beam computed tomography (CBCT). Dental CBCT was used in this study to evaluate dental implant sites for (1) differences in and (2) correlations between cancellous bone density and cortical bone thickness among four regions of the jawbone. In total, 315 dental implant sites (39 in the anterior mandible, 42 in the anterior maxilla, 107 in the posterior mandible, and 127 in the posterior maxilla) were identified in dental CBCT images from 128 patients. All CBCT images were loaded into Mimics 15.0 to measure cancellous bone density (unit: grayscale value (GV) and cortical bone thickness (unit: mm)). Differences among the four regions of the jawbone were evaluated using one-way analysis of variance and Scheffe’s posttest. Pearson coefficients for correlations between cancellous bone dens...

Applied Sciences

The objective of this study was to evaluate and compare the biomechanical behavior of internal fi... more The objective of this study was to evaluate and compare the biomechanical behavior of internal fixation techniques in bilateral sagittal split ramus osteotomies (BSSROs) for mandibular setback. Artificial polyurethane mandibles were used in this study. The distal segment of the mandible was repositioned in an 8-mm setback position. All mandibles were divided into three groups: Group 1 had a straight plate with a four-hole monocortical fixation, Group 2 had a curved plate with a four-hole monocortical fixation, and Group 3 had a three–inverted L-type bicortical screw fixation. Vertical loads were applied on the incisal edge by a material testing system. The resistance force at 1, 3, 5, and 10 mm of displacement was analyzed. From the experimental results, Group 1 showed significantly lower results than Groups 2 and 3. No significant difference was observed between Groups 2 and 3 at 1, 3, and 5 mm of displacement. However, at 10 mm of displacement, the resistance force of Group 3 was ...

International Journal of Environmental Research and Public Health

Satisfactory host bone quality and quantity promote greater primary stability and better osseoint... more Satisfactory host bone quality and quantity promote greater primary stability and better osseointegration, leading to a high success rate in the use of dental implants. However, the increase in life expectancy as a result of medical advancements has led to an aging population, suggesting that osteoporosis may become a problem in clinical dental implant surgery. Notably, relative to the general population, bone insufficiency is more common in women with post-menopausal osteoporosis. The objective of this study was to compare the thickness of the crestal cortical bone at prospective dental implant sites between menopausal and non-menopausal women. Prospective dental implant sites in the jawbone were evaluated in two groups of women: a younger group (<50 years old), with 149 sites in 48 women, and an older group (>50 years old) with 191 sites, in 37 women. The thickness of the crestal cortical bone at the dental implant site was measured based on each patient’s dental cone-beam c...

Applied Sciences

We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and... more We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial and complete mandibles based on dental cone beam computed tomography images of the human skull. Additionally, we exerted an orthodontic force on the canine crown in the direction of an orthodontic miniscrew under a lower molar root to compare the von Mises strain on the canine PDL in three models: a partial mandible model under orthodontic force (Model 1), a complete mandible model under orthodontic force (Model 2), and a complete mandible model under orthodontic force with clench occlusion in the intercuspal position (ICP; Model 3). Additionally, in the complete mandible model under orthodontic force with ICP occlusion, we analyzed the effects of a PDL with a low (Model 4), moderate (M...

Metals

In finite element (FE) simulations, the peak bone stresses were higher when loading with a cantil... more In finite element (FE) simulations, the peak bone stresses were higher when loading with a cantilever extension (CE) than when loading without a CE by 33–49% in the cortical bone. In the in vitro experiments, the highest values of principal strain were all within the range of the minimum principal strain, and those peak bone strains were 40–58% greater when loading with a CE than when loading without a CE (p < 0.001). This study investigated how varying the implanted position and angulation of anterior implants in the All-on-Four treatment influenced the biomechanical environment in the alveolar bone around the dental implants. Ten numerical simulations of FE models and three in vitro samples of All-on-Four treatment of dental implants were created to investigate the effects of altering the implanted position and angulation type of anterior implants. A single load of 100 N was applied in the molar region in the presence or absence of a CE of the denture. The 3D FE simulations ana...

Applied Sciences

The objective of this study was to develop a geometrical calibration method applicable to the 2.5... more The objective of this study was to develop a geometrical calibration method applicable to the 2.5D prototype Periapical Radiography System and estimate component position errors. A two-steel-ball phantom with a precisely known position was placed in front of a digital X-ray sensor for two-stage calibration. In the first stage, the following three parameters were estimated: (1) r, the distance between the focal spot and the rotation axis of the X-ray tube; (2) ψ, the included angle between the straight line formed by the X-ray tube’s focal spot and rotation axis and the straight line of the orthogonal sensor; and (3) L4, the distance between the rotation axis and the plane where the two steel balls were positioned. In the second stage, the steel balls’ positions were determined to calculate the positions of the X-ray tube on the x, y, and z axes. Computer simulation was used to verify the accuracy of the calibration method. The results indicate that for the calibration approach propo...

Journal of Mechanics in Medicine and Biology

Purpose: This study investigated the effects of the contact percentage (BMC%) of three-dimensiona... more Purpose: This study investigated the effects of the contact percentage (BMC%) of three-dimensional (3D) bone-to-miniscrew specimens in relation to host bone quality on initial miniscrew stability. Furthermore, their correlations were evaluated. Methods: Orthodontic miniscrews (1.6[Formula: see text]mm in diameter and 11[Formula: see text]mm in length) were inserted into four types of artificial bones to measure the maximum insertion torque value (ITV). The miniscrew and artificial foam bone specimens were also scanned using microcomputed tomography, and the obtained images were imported into Mimics software to reconstruct the 3D models and calculate the BMC%. The Kruskal–Wallis test, Wilcoxon rank-sum test with Bonferroni adjustment, and Spearman correlations were applied for statistical and correlation analyses. Results and Conclusions: Inserting the orthodontic miniscrew into artificial foam bone exhibiting higher bone quality resulted in higher maximum ITV and BMC%. The initial i...

Surface and Coatings Technology

The Journal of prosthetic dentistry, Jan 29, 2016

The quality of maxillary bone is generally lower than that of mandibular bone; consequently, comp... more The quality of maxillary bone is generally lower than that of mandibular bone; consequently, complete arch immediate implant-loading treatment is not as predictable in the maxillary as in the mandibular arch. The All-on-4 concept has proven to be an effective and successful treatment protocol. However, the survival rate of All-on-4 implants in the maxilla is lower than of those in the mandible. In this report, 2 anterior wide-diameter implants were used with the All-on-4 concept for a maxillary rehabilitation to provide biomechanical benefits with better primary stability while still achieving a functional and esthetic result. The clinical challenges of using wide-diameter implants in the anterior region are also discussed and should be considered during treatment planning.

BMC medical imaging, Jan 7, 2015

Before extracting impacted lower third molars, dentists must first identify the spatial relations... more Before extracting impacted lower third molars, dentists must first identify the spatial relationship between the inferior alveolar nerve (IAN) and an impacted lower third molar to prevent nerve injury from the extraction. Nevertheless, the current method for describing the spatial relationship between the IAN and an impacted lower third molar is deficient. Therefore, the objectives of this study were to: (1) evaluate the relative position between impacted lower third molars and the IAN; and (2) investigate the relative position between impacted lower third molars and the IAN by using a cylindrical coordinate system. From the radiology department's database, we selected computed tomography images of 137 lower third molars (from 75 patients) requiring removal and applied a Cartesian coordinate system by using Mimics, a medical imaging software application, to measure the distribution between impacted mandibular third molars and the IAN. In addition, the orientation of the lower th...

The International journal of oral & maxillofacial implants

ABSTRACT

The Journal of Prosthetic Dentistry, 2015

Use of a small diameter implant may increase the stress on bone around the implant neck; however,... more Use of a small diameter implant may increase the stress on bone around the implant neck; however, an expanded platform design may mitigate these stress concentrations. To date, no study has compared the biomechanical effect of regular platform and extended platform designs on an implant. The purpose of this in vitro study was to evaluate the biomechanical effects of an expanded platform-switching design for immediately loaded small diameter implants on bone strains. Three groups of artificial jawbone models were prepared for small diameter (3.25-mm) and standard diameter (4.0-mm) implants with expanded or regular platform designs. Platform-switching implant design was implemented by assembling implants with a smaller connected abutment. Specimens were tested under both vertical and lateral static loads at 190 N. Peak values of the principal microstrain of bone were recorded and analyzed statistically with Kruskal-Wallis test and multiple comparisons Bonferroni test (α=.05). The initial stability of each implant was also measured for 3 types of implant. Under vertical loading, the bone strain was lowest for the regular type of immediately loaded small diameter implant. Under lateral loading, peak bone strain around the expanded platform small diameter implant with platform switched abutment was up to 74.9% lower than that of the regular type of small diameter implant. Increasing the implant diameter from 3.25 mm to 4.0 mm on the expanded platform implants reduced the bone strain by approximately 10% and 30% under lateral and vertical loading, respectively. The initial implant stability did not vary significantly among the implants tested. Using the expanded platform small diameter implant with a platform-switched abutment may decrease the marginal bone strains around immediately loaded small-diameter implants under lateral loading.

Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery, Jan 2, 2015

The objective of this study was to evaluate the effect of clenching tasks on the stress and stabi... more The objective of this study was to evaluate the effect of clenching tasks on the stress and stability of a temporomandibular joint (TMJ) condylar prosthesis, as well as on the stress and strain in the whole mandible and bone surrounding three screws. Three-dimensional finite element models of the mandible and a TMJ condylar prosthesis using three screws were established. Six static clenching tasks were simulated in this study: incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), left unilateral molar clench (LMOL), right group function (RGF), and left group function (LGF). Based on the simulation of the six clenching tasks, none of the inserted screws or the TMJ condylar prosthesis were broken. In addition, the stability of the TMJ condylar prosthesis was sufficiently high for bone ongrowth. For the whole mandibular bone, the maximum von Mises stress and von Mises strain observed in the cortical bone and cancellous bone were yielded by the ICP and ...

IFMBE Proceedings, 2009

... Jui-Ting Hsu 1 , Li-Chun Wu 1 , Yin-Yu Chang 2 , Tzu-Ning Weng 1 , Heng-Li Huang 1 , Chein-Hu... more ... Jui-Ting Hsu 1 , Li-Chun Wu 1 , Yin-Yu Chang 2 , Tzu-Ning Weng 1 , Heng-Li Huang 1 , Chein-Hung Yu 1,3 ... Archwires constructed from the following three types of metal were selected: stainless steel archwire (SS wire, Sin-Yean, Taipei, Taiwan), Sentalloy NiTi-alloy archwire ...

The International journal of oral & maxillofacial implants

Ideally, implants for dental prostheses should be placed parallel to each other. However, anatomi... more Ideally, implants for dental prostheses should be placed parallel to each other. However, anatomic limitations sometimes make nonparallel implants necessary. The purpose of this study was to determine the bone stresses on implants tilted at various angles and to determine what arrangements might carry a higher risk of failure. Three-dimensional finite element models were constructed using the mean values measured for the Asian mandible in the first and second molar areas. Eight implants were divided into three tilting types: parallel implants (P1(PP), P2(MM), and P3(DD)), convergent implant apices (C1(PD) and C2(MP)), and divergent implant apices (D1(DP), D2(DM), and D3(PM)). A biting load of 200 N was applied vertically and obliquely on the occlusal central fossa of the splinted crowns. The main effects of each level of the three investigated factors (loading type, relationship of implant apices, and distal tilting of one or both implants) in terms of the stress values were compute...

Journal of endodontics, 2009

This study determined the prevalence of permanent three-rooted mandibular first molars and their ... more This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744 patients were screened to obtain 123 samples for this study. All permanent mandibular first molars were evaluated in axial sections from the pulpal floor to the apices of the roots to determine the number of roots. The interorifice distances from the distolingual (DL) canal to the mesiobuccal (MB) and distobuccal (DB) canals were also estimated. The prevalence of permanent three-rooted mandibular first molars was 33.33%, with a bilateral incidence of a symmetrical distribution of 53.65%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence.The mean interorifice distances from the DL canal to the DB, MB, and ML canals of the permanent three-root...

The International journal of oral & maxillofacial implants

Stress analysis was performed for various implant designs using 3-dimensional finite element anal... more Stress analysis was performed for various implant designs using 3-dimensional finite element analysis approaches. Six implant designs were included: 3 parallel-sided implants (no thread, triangular thread, and squared thread), 2 stepped configurations (non-thread and triangular thread), and a tapered body of implant with squared thread. All threads had spiral characteristics. The mandibular model was constructed from computed tomographic (CT) images of a human mandible, and the material properties were anisotropic (different in different directions). A 100-N oblique force was applied at a 45-degree angle to the long axis of the implants at the buccal cusp as the loading condition. Compared with cylindric implants, threaded implants (either triangular or squared) demonstrated increased peak stress at the crestal bone. The bone stress of stepped implants was decreased in the cortical region but was increased in the trabecular region. However, both threaded and stepped designs showed d...

The International Journal of Oral & Maxillofacial Implants, 2013

This assignment applies to all translations of the Work as well as to preliminary display/posting... more This assignment applies to all translations of the Work as well as to preliminary display/posting of the abstract of the accepted article in electronic form before publication. If any changes in authorship (order, deletions, or additions) occur after the manuscript is submitted, agreement by all authors for such changes must be on file with the Publisher. An author's name may be removed only at his/her written request. (Note: Material prepared by employees of the US government in the course of their official duties cannot be copyrighted.

Thin Solid Films, 2013

ABSTRACT This study used a twin-gun magnetron sputtering system to deposit ZrO2-silver (Ag) coati... more ABSTRACT This study used a twin-gun magnetron sputtering system to deposit ZrO2-silver (Ag) coatings on biograde pure-titanium implant materials, and the Ag content in the deposited coatings was controlled by the magnetron power. The films were then annealed using rapid thermal annealing at 350 °C for 2 min to induce the nucleation and growth of nanoparticles on the film surface. Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) were used for in vitro antibacterial analyses. The cytocompatibility, mRNA expression, and adhesive morphology of human gingival fibroblast (HGF) cells on the coatings were also determined. The obtained results suggest that ZrO2-Ag composite coatings containing less than 10.6 at.% Ag show hydrophobicity, good viability and proliferation of HGF cells, and antibacterial effects on S. aureus and A. actinomycetemcomitans. Moreover, the antibacterial performance of ZrO2-Ag coatings is superior to that pure-titanium whilst maintaining biological compatibility.

International Journal of Environmental Research and Public Health

Dental implants are among the most common treatments for missing teeth. The thickness of the cres... more Dental implants are among the most common treatments for missing teeth. The thickness of the crestal cortical bone at the potential dental implant site is a critical factor affecting the success rate of dental implant surgery. However, previous studies have predominantly focused on female patients, who are at a high risk of osteoporosis, for the discussion of bone quality and quantity at the dental implant site. This study aimed to investigate the effect of male patients’ age on the crestal cortical bone of the jaw at the dental implant site by using dental cone-beam computed tomography (CBCT). This study performed dental CBCT on 84 male patients of various ages to obtain tomograms of 288 dental implant sites at the jawbone (41 sites in the anterior maxilla, 95 in the posterior maxilla, 59 in the anterior mandible, and 93 in the posterior mandible) for measuring the cortical bone thickness. A one-way analysis of variance and Scheffe’s test were performed on the measurement results t...

Diagnostics

Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably... more Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably affected by host bone quality and quantity, which is often assessed prior to surgery through dental cone-beam computed tomography (CBCT). Dental CBCT was used in this study to evaluate dental implant sites for (1) differences in and (2) correlations between cancellous bone density and cortical bone thickness among four regions of the jawbone. In total, 315 dental implant sites (39 in the anterior mandible, 42 in the anterior maxilla, 107 in the posterior mandible, and 127 in the posterior maxilla) were identified in dental CBCT images from 128 patients. All CBCT images were loaded into Mimics 15.0 to measure cancellous bone density (unit: grayscale value (GV) and cortical bone thickness (unit: mm)). Differences among the four regions of the jawbone were evaluated using one-way analysis of variance and Scheffe’s posttest. Pearson coefficients for correlations between cancellous bone dens...

Applied Sciences

The objective of this study was to evaluate and compare the biomechanical behavior of internal fi... more The objective of this study was to evaluate and compare the biomechanical behavior of internal fixation techniques in bilateral sagittal split ramus osteotomies (BSSROs) for mandibular setback. Artificial polyurethane mandibles were used in this study. The distal segment of the mandible was repositioned in an 8-mm setback position. All mandibles were divided into three groups: Group 1 had a straight plate with a four-hole monocortical fixation, Group 2 had a curved plate with a four-hole monocortical fixation, and Group 3 had a three–inverted L-type bicortical screw fixation. Vertical loads were applied on the incisal edge by a material testing system. The resistance force at 1, 3, 5, and 10 mm of displacement was analyzed. From the experimental results, Group 1 showed significantly lower results than Groups 2 and 3. No significant difference was observed between Groups 2 and 3 at 1, 3, and 5 mm of displacement. However, at 10 mm of displacement, the resistance force of Group 3 was ...

International Journal of Environmental Research and Public Health

Satisfactory host bone quality and quantity promote greater primary stability and better osseoint... more Satisfactory host bone quality and quantity promote greater primary stability and better osseointegration, leading to a high success rate in the use of dental implants. However, the increase in life expectancy as a result of medical advancements has led to an aging population, suggesting that osteoporosis may become a problem in clinical dental implant surgery. Notably, relative to the general population, bone insufficiency is more common in women with post-menopausal osteoporosis. The objective of this study was to compare the thickness of the crestal cortical bone at prospective dental implant sites between menopausal and non-menopausal women. Prospective dental implant sites in the jawbone were evaluated in two groups of women: a younger group (<50 years old), with 149 sites in 48 women, and an older group (>50 years old) with 191 sites, in 37 women. The thickness of the crestal cortical bone at the dental implant site was measured based on each patient’s dental cone-beam c...

Applied Sciences

We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and... more We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial and complete mandibles based on dental cone beam computed tomography images of the human skull. Additionally, we exerted an orthodontic force on the canine crown in the direction of an orthodontic miniscrew under a lower molar root to compare the von Mises strain on the canine PDL in three models: a partial mandible model under orthodontic force (Model 1), a complete mandible model under orthodontic force (Model 2), and a complete mandible model under orthodontic force with clench occlusion in the intercuspal position (ICP; Model 3). Additionally, in the complete mandible model under orthodontic force with ICP occlusion, we analyzed the effects of a PDL with a low (Model 4), moderate (M...

Metals

In finite element (FE) simulations, the peak bone stresses were higher when loading with a cantil... more In finite element (FE) simulations, the peak bone stresses were higher when loading with a cantilever extension (CE) than when loading without a CE by 33–49% in the cortical bone. In the in vitro experiments, the highest values of principal strain were all within the range of the minimum principal strain, and those peak bone strains were 40–58% greater when loading with a CE than when loading without a CE (p < 0.001). This study investigated how varying the implanted position and angulation of anterior implants in the All-on-Four treatment influenced the biomechanical environment in the alveolar bone around the dental implants. Ten numerical simulations of FE models and three in vitro samples of All-on-Four treatment of dental implants were created to investigate the effects of altering the implanted position and angulation type of anterior implants. A single load of 100 N was applied in the molar region in the presence or absence of a CE of the denture. The 3D FE simulations ana...

Applied Sciences

The objective of this study was to develop a geometrical calibration method applicable to the 2.5... more The objective of this study was to develop a geometrical calibration method applicable to the 2.5D prototype Periapical Radiography System and estimate component position errors. A two-steel-ball phantom with a precisely known position was placed in front of a digital X-ray sensor for two-stage calibration. In the first stage, the following three parameters were estimated: (1) r, the distance between the focal spot and the rotation axis of the X-ray tube; (2) ψ, the included angle between the straight line formed by the X-ray tube’s focal spot and rotation axis and the straight line of the orthogonal sensor; and (3) L4, the distance between the rotation axis and the plane where the two steel balls were positioned. In the second stage, the steel balls’ positions were determined to calculate the positions of the X-ray tube on the x, y, and z axes. Computer simulation was used to verify the accuracy of the calibration method. The results indicate that for the calibration approach propo...

Journal of Mechanics in Medicine and Biology

Purpose: This study investigated the effects of the contact percentage (BMC%) of three-dimensiona... more Purpose: This study investigated the effects of the contact percentage (BMC%) of three-dimensional (3D) bone-to-miniscrew specimens in relation to host bone quality on initial miniscrew stability. Furthermore, their correlations were evaluated. Methods: Orthodontic miniscrews (1.6[Formula: see text]mm in diameter and 11[Formula: see text]mm in length) were inserted into four types of artificial bones to measure the maximum insertion torque value (ITV). The miniscrew and artificial foam bone specimens were also scanned using microcomputed tomography, and the obtained images were imported into Mimics software to reconstruct the 3D models and calculate the BMC%. The Kruskal–Wallis test, Wilcoxon rank-sum test with Bonferroni adjustment, and Spearman correlations were applied for statistical and correlation analyses. Results and Conclusions: Inserting the orthodontic miniscrew into artificial foam bone exhibiting higher bone quality resulted in higher maximum ITV and BMC%. The initial i...

Surface and Coatings Technology

The Journal of prosthetic dentistry, Jan 29, 2016

The quality of maxillary bone is generally lower than that of mandibular bone; consequently, comp... more The quality of maxillary bone is generally lower than that of mandibular bone; consequently, complete arch immediate implant-loading treatment is not as predictable in the maxillary as in the mandibular arch. The All-on-4 concept has proven to be an effective and successful treatment protocol. However, the survival rate of All-on-4 implants in the maxilla is lower than of those in the mandible. In this report, 2 anterior wide-diameter implants were used with the All-on-4 concept for a maxillary rehabilitation to provide biomechanical benefits with better primary stability while still achieving a functional and esthetic result. The clinical challenges of using wide-diameter implants in the anterior region are also discussed and should be considered during treatment planning.

BMC medical imaging, Jan 7, 2015

Before extracting impacted lower third molars, dentists must first identify the spatial relations... more Before extracting impacted lower third molars, dentists must first identify the spatial relationship between the inferior alveolar nerve (IAN) and an impacted lower third molar to prevent nerve injury from the extraction. Nevertheless, the current method for describing the spatial relationship between the IAN and an impacted lower third molar is deficient. Therefore, the objectives of this study were to: (1) evaluate the relative position between impacted lower third molars and the IAN; and (2) investigate the relative position between impacted lower third molars and the IAN by using a cylindrical coordinate system. From the radiology department's database, we selected computed tomography images of 137 lower third molars (from 75 patients) requiring removal and applied a Cartesian coordinate system by using Mimics, a medical imaging software application, to measure the distribution between impacted mandibular third molars and the IAN. In addition, the orientation of the lower th...

The International journal of oral & maxillofacial implants

ABSTRACT

The Journal of Prosthetic Dentistry, 2015

Use of a small diameter implant may increase the stress on bone around the implant neck; however,... more Use of a small diameter implant may increase the stress on bone around the implant neck; however, an expanded platform design may mitigate these stress concentrations. To date, no study has compared the biomechanical effect of regular platform and extended platform designs on an implant. The purpose of this in vitro study was to evaluate the biomechanical effects of an expanded platform-switching design for immediately loaded small diameter implants on bone strains. Three groups of artificial jawbone models were prepared for small diameter (3.25-mm) and standard diameter (4.0-mm) implants with expanded or regular platform designs. Platform-switching implant design was implemented by assembling implants with a smaller connected abutment. Specimens were tested under both vertical and lateral static loads at 190 N. Peak values of the principal microstrain of bone were recorded and analyzed statistically with Kruskal-Wallis test and multiple comparisons Bonferroni test (α=.05). The initial stability of each implant was also measured for 3 types of implant. Under vertical loading, the bone strain was lowest for the regular type of immediately loaded small diameter implant. Under lateral loading, peak bone strain around the expanded platform small diameter implant with platform switched abutment was up to 74.9% lower than that of the regular type of small diameter implant. Increasing the implant diameter from 3.25 mm to 4.0 mm on the expanded platform implants reduced the bone strain by approximately 10% and 30% under lateral and vertical loading, respectively. The initial implant stability did not vary significantly among the implants tested. Using the expanded platform small diameter implant with a platform-switched abutment may decrease the marginal bone strains around immediately loaded small-diameter implants under lateral loading.

Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery, Jan 2, 2015

The objective of this study was to evaluate the effect of clenching tasks on the stress and stabi... more The objective of this study was to evaluate the effect of clenching tasks on the stress and stability of a temporomandibular joint (TMJ) condylar prosthesis, as well as on the stress and strain in the whole mandible and bone surrounding three screws. Three-dimensional finite element models of the mandible and a TMJ condylar prosthesis using three screws were established. Six static clenching tasks were simulated in this study: incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), left unilateral molar clench (LMOL), right group function (RGF), and left group function (LGF). Based on the simulation of the six clenching tasks, none of the inserted screws or the TMJ condylar prosthesis were broken. In addition, the stability of the TMJ condylar prosthesis was sufficiently high for bone ongrowth. For the whole mandibular bone, the maximum von Mises stress and von Mises strain observed in the cortical bone and cancellous bone were yielded by the ICP and ...

IFMBE Proceedings, 2009

... Jui-Ting Hsu 1 , Li-Chun Wu 1 , Yin-Yu Chang 2 , Tzu-Ning Weng 1 , Heng-Li Huang 1 , Chein-Hu... more ... Jui-Ting Hsu 1 , Li-Chun Wu 1 , Yin-Yu Chang 2 , Tzu-Ning Weng 1 , Heng-Li Huang 1 , Chein-Hung Yu 1,3 ... Archwires constructed from the following three types of metal were selected: stainless steel archwire (SS wire, Sin-Yean, Taipei, Taiwan), Sentalloy NiTi-alloy archwire ...

The International journal of oral & maxillofacial implants

Ideally, implants for dental prostheses should be placed parallel to each other. However, anatomi... more Ideally, implants for dental prostheses should be placed parallel to each other. However, anatomic limitations sometimes make nonparallel implants necessary. The purpose of this study was to determine the bone stresses on implants tilted at various angles and to determine what arrangements might carry a higher risk of failure. Three-dimensional finite element models were constructed using the mean values measured for the Asian mandible in the first and second molar areas. Eight implants were divided into three tilting types: parallel implants (P1(PP), P2(MM), and P3(DD)), convergent implant apices (C1(PD) and C2(MP)), and divergent implant apices (D1(DP), D2(DM), and D3(PM)). A biting load of 200 N was applied vertically and obliquely on the occlusal central fossa of the splinted crowns. The main effects of each level of the three investigated factors (loading type, relationship of implant apices, and distal tilting of one or both implants) in terms of the stress values were compute...

Journal of endodontics, 2009

This study determined the prevalence of permanent three-rooted mandibular first molars and their ... more This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744 patients were screened to obtain 123 samples for this study. All permanent mandibular first molars were evaluated in axial sections from the pulpal floor to the apices of the roots to determine the number of roots. The interorifice distances from the distolingual (DL) canal to the mesiobuccal (MB) and distobuccal (DB) canals were also estimated. The prevalence of permanent three-rooted mandibular first molars was 33.33%, with a bilateral incidence of a symmetrical distribution of 53.65%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence.The mean interorifice distances from the DL canal to the DB, MB, and ML canals of the permanent three-root...

The International journal of oral & maxillofacial implants

Stress analysis was performed for various implant designs using 3-dimensional finite element anal... more Stress analysis was performed for various implant designs using 3-dimensional finite element analysis approaches. Six implant designs were included: 3 parallel-sided implants (no thread, triangular thread, and squared thread), 2 stepped configurations (non-thread and triangular thread), and a tapered body of implant with squared thread. All threads had spiral characteristics. The mandibular model was constructed from computed tomographic (CT) images of a human mandible, and the material properties were anisotropic (different in different directions). A 100-N oblique force was applied at a 45-degree angle to the long axis of the implants at the buccal cusp as the loading condition. Compared with cylindric implants, threaded implants (either triangular or squared) demonstrated increased peak stress at the crestal bone. The bone stress of stepped implants was decreased in the cortical region but was increased in the trabecular region. However, both threaded and stepped designs showed d...

The International Journal of Oral & Maxillofacial Implants, 2013

This assignment applies to all translations of the Work as well as to preliminary display/posting... more This assignment applies to all translations of the Work as well as to preliminary display/posting of the abstract of the accepted article in electronic form before publication. If any changes in authorship (order, deletions, or additions) occur after the manuscript is submitted, agreement by all authors for such changes must be on file with the Publisher. An author's name may be removed only at his/her written request. (Note: Material prepared by employees of the US government in the course of their official duties cannot be copyrighted.

Thin Solid Films, 2013

ABSTRACT This study used a twin-gun magnetron sputtering system to deposit ZrO2-silver (Ag) coati... more ABSTRACT This study used a twin-gun magnetron sputtering system to deposit ZrO2-silver (Ag) coatings on biograde pure-titanium implant materials, and the Ag content in the deposited coatings was controlled by the magnetron power. The films were then annealed using rapid thermal annealing at 350 °C for 2 min to induce the nucleation and growth of nanoparticles on the film surface. Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) were used for in vitro antibacterial analyses. The cytocompatibility, mRNA expression, and adhesive morphology of human gingival fibroblast (HGF) cells on the coatings were also determined. The obtained results suggest that ZrO2-Ag composite coatings containing less than 10.6 at.% Ag show hydrophobicity, good viability and proliferation of HGF cells, and antibacterial effects on S. aureus and A. actinomycetemcomitans. Moreover, the antibacterial performance of ZrO2-Ag coatings is superior to that pure-titanium whilst maintaining biological compatibility.