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1.
BMC Emerg Med ; 24(1): 79, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38710999

ABSTRACT

BACKGROUND: This study compared out-of-hospital cardiac arrest (OHCA) patient outcomes based on intravenous (IV) access and prehospital epinephrine use. METHODS: A retrospective study in Ulsan, South Korea, from January 2017 to December 2022, analyzed adult nontraumatic OHCA cases. Patients were grouped: Group 1 (no IV attempts), Group 2 (failed IV access), Group 3 (successful IV access without epinephrine), and Group 4 (successful IV access with epinephrine), with comparisons using logistic regression analysis. RESULTS: Among 2,656 patients, Group 4 had significantly lower survival to hospital discharge (adjusted OR 0.520, 95% CI 0.346-0.782, p = 0.002) and favorable neurological outcomes (adjusted OR 0.292, 95% CI 0.140-0.611, p = 0.001) than Group 1. Groups 2 and 3 showed insignificant survival to hospital discharge (adjusted OR 0.814, 95% CI 0.566-1.171, p = 0.268) and (adjusted OR 1.069, 95% CI 0.810-1.412, p = 0.636) and favorable neurological outcomes (adjusted OR 0.585, 95% CI 0.299-1.144, p = 0.117) and (adjusted OR 1.075, 95% CI 0.689-1.677, p = 0.751). In the shockable rhythm group, Group 3 had better survival to hospital discharge (adjusted OR 1.700, 95% CI 1.044-2.770, p = 0.033). CONCLUSIONS: Successful IV access with epinephrine showed worse outcomes in both rhythm groups than no IV attempts. Outcomes for failed IV and successful IV access without epinephrine were inconclusive. Importantly, successful IV access without epinephrine showed favorable survival to hospital discharge in the shockable rhythm group, warranting further research into IV access for fluid resuscitation in shockable rhythm OHCA patients.


Subject(s)
Emergency Medical Services , Epinephrine , Out-of-Hospital Cardiac Arrest , Humans , Out-of-Hospital Cardiac Arrest/mortality , Out-of-Hospital Cardiac Arrest/drug therapy , Out-of-Hospital Cardiac Arrest/therapy , Epinephrine/administration & dosage , Male , Female , Retrospective Studies , Republic of Korea , Middle Aged , Aged , Cardiopulmonary Resuscitation , Adult , Administration, Intravenous
2.
Foods ; 12(12)2023 Jun 07.
Article in English | MEDLINE | ID: mdl-37372515

ABSTRACT

Shortwave infrared (SWIR) hyperspectral imaging was applied to classify the freshness of mackerels. Total volatile basic nitrogen (TVB-N) and acid values, as chemical compounds related to the freshness of mackerels, were also analyzed to develop a prediction model of freshness by combining them with hyperspectral data. Fresh mackerels were divided into three groups according to storage periods (0, 24, and 48 h), and hyperspectral data were collected from the eyes and whole body, separately. The optimized classification accuracies were 81.68% using raw data from eyes and 90.14% using body data by multiple scatter correction (MSC) pretreatment. The prediction accuracy of TVB-N was 90.76%, and the acid value was 83.76%. These results indicate that hyperspectral imaging, as a nondestructive method, can be used to verify the freshness of mackerels and predict the chemical compounds related to the freshness.

3.
Sci Rep ; 13(1): 1403, 2023 01 25.
Article in English | MEDLINE | ID: mdl-36697453

ABSTRACT

This study aimed to validate the predictive performance of the termination of resuscitation (TOR) rule and examine the compression time interval (CTI) as a criterion for modifying the rule. This retrospective observational study analyzed adult out-of-hospital cardiac arrest (OHCA) patients attended by emergency medical service (EMS) providers in mixed urban-rural areas in Korea in 2020 and 2021. We evaluated the predictive performance of basic life support (BLS) and the Korean Cardiac Arrest Research Consortium (KoCARC) TOR rule using the false-positive rate (FPR) and positive predictive value (PPV). We modified the age cutoff criterion and examined the CTI as a new criterion. According to the TOR rule, 1827 OHCA patients were classified into two groups. The predictive performance of the BLS TOR rule had an FPR of 11.7% (95% confidence interval (CI): 5.9-17.5) and PPV of 98.4% (97.6-99.2) for mortality, and an FPR of 3.6% (0.0-7.8) and PPV of 78.6% (75.9-81.3) for poor neurological outcomes at hospital discharge. The predictive performance of the KoCARC TOR rule had an FPR of 5.0% (1.1-8.9) and PPV of 98.9% (98.0-99.8) for mortality, and an FPR of 3.7% (0.0-7.8) and PPV of 50.0% (45.7-54.3) for poor neurological outcomes at hospital discharge. The modified cutoff value for age was 68 years, with an area under the receiver operating characteristic curve over 0.7. In the group that met the BLS TOR rule, the cutoff of the CTI for death was not determined and was 21 min for poor neurological outcomes. In the group that met the KoCARC TOR rule, the cutoff of the CTI for death and poor neurological outcomes at the time of hospital discharge was 25 min and 21 min, respectively. The BLS TOR and KoCARC TOR rules showed inappropriate predictive performance for mortality and poor neurological outcomes. However, the predictive performance of the TOR rule could be supplemented by modifying the age criterion and adding the CTI criterion of the KoCARC.


Subject(s)
Cardiopulmonary Resuscitation , Out-of-Hospital Cardiac Arrest , Adult , Humans , Aged , Resuscitation Orders , Decision Support Techniques , Out-of-Hospital Cardiac Arrest/therapy , Republic of Korea
4.
Injury ; 54(2): 598-603, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36400630

ABSTRACT

This study analyzed the outcomes of bilateral internal iliac artery (IIA) ligation with preperitoneal pelvic packing (PPP) in hemodynamically unstable patients with major pelvic fractures. All-cause mortality was examined, periprocedural safety for critical circumstances was reviewed, and iliac artery ligation-related complications of the postoperative phase were evaluated. A total of 20 patients who suffered substantially from severe pelvic trauma with hemodynamic instability and subsequently underwent bilateral IIA ligation with PPP between January 1, 2017, and December 31, 2021, were enrolled in the study. The median participant age was 60.5 years, and 65.0% were male. The median systolic blood pressure was 68.5 mmHg on arrival. Increased lactate level (median, 11.05 mmol/L) suggested that the patients were in shock distinctly due to hypovolemia. It took approximately 1 h to complete the ligation of bilateral IIA to accomplish hemostasis (median, 65.5 min). The iliac vein was injured during dissection in three cases. During the ICU stay (median, 17.5 days), acute kidney injury was identified in 13 patients, likely due to volume depletion. The median ventilator-free days was 13.5; six patients were confirmed with ventilator-associated pneumonia. Moreover, 12 patients were diagnosed with acute respiratory distress syndrome. There was one case in which the lower extremity artery was acutely occluded. Anatomic hemostasis was achieved in 18 patients. The two patients for which anatomic hemostasis failed became two mortality cases from preperitoneal hemorrhage. Our analysis showed that bilateral IIA ligation with PPP was effective as a lifesaving procedure in hemodynamically unstable patients with a major pelvic fracture in terms of mortality due to fracture-related exsanguination. Moreover, the incidence of periprocedural complications was considered tolerable, making the procedure worth a try, especially in austere and underdeveloped healthcare settings.


Subject(s)
Fractures, Bone , Pelvic Bones , Humans , Male , Middle Aged , Female , Iliac Artery/surgery , Fractures, Bone/complications , Fractures, Bone/surgery , Pelvis/surgery , Hemorrhage/surgery , Hemorrhage/complications , Pelvic Bones/surgery , Pelvic Bones/injuries , Retrospective Studies
5.
J Clin Med ; 11(14)2022 Jul 21.
Article in English | MEDLINE | ID: mdl-35888012

ABSTRACT

This retrospective study aimed to compare the survival outcomes of adult out-of-hospital cardiac arrest (OHCA) patients between urban (Busan, Ulsan, Changwon) and rural (Gyeongnam) areas in South Korea and identify modifiable factors in the chain of survival. The primary and secondary outcomes were survival to discharge and modifiable factors in the chain of survival were identified using logistic regression analysis. In total, 1954 patients were analyzed. The survival to discharge rates in the whole region and in urban and rural areas were 6.9%, 8.7% (Busan 8.7%, Ulsan 10.3%, Changwon 7.2%), and 3.4%, respectively. In the urban group, modifiable factors associated with survival to discharge were no advanced airway management (adjusted odds ratio (aOR) 2.065, 95% confidence interval (CI): 1.138-3.747), no mechanical chest compression (aOR 3.932, 95% CI: 2.015-7.674), and an emergency medical service (EMS) transport time of more than 8 min (aOR 3.521, 95% CI: 2.075-5.975). In the rural group, modifiable factors included an EMS scene time of more than 15 min (aOR 0.076, 95% CI: 0.006-0.883) and an EMS transport time of more than 8 min (aOR 4.741, 95% CI: 1.035-21.706). To improve survival outcomes, dedicated resources and attention to EMS practices and transport time in urban areas and EMS scene and transport times in rural areas are needed.

6.
J Oral Implantol ; 48(6): 578-583, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-35881817

ABSTRACT

The objective of this study was to evaluate the effect of anchor-guiding sleeve length on the accuracy of computer-guided flapless implant surgery in edentulous cases. Twelve identical polyurethane edentulous mandibular models were equally divided into short and long anchor-guiding sleeve groups based on the type of anchor-guiding sleeve. After implant placement and scan body connections, digital impressions were taken using the intraoral scanner. Using the software's measurement function, the deviation parameters between the planned and actual position of the placed implants were calculated and compared using the Mann-Whitney U test. In the short anchor-guiding sleeve group, the median angular deviation was 4.05° (range, 2.87°-7.55°). The median linear deviation was 1.17 mm (range, 0.24-2.17 mm) for the implant apex and 0.82 mm (range, 0.43-1.67 mm) for the implant shoulder. The median deviation of the depth was 0.31 mm (range, 0.20-0.79 mm). In the long anchor-guiding sleeve group, the median angular deviation was 2.70° (range, 1.77°-4.08°). The median linear deviation was 0.88 mm (range, 0.21-1.77 mm) for the implant apex and 0.63 mm (range, 0.11-1.97 mm) for the implant shoulder. The median deviation of the depth was 0.24 mm (range, 0.09-0.53 mm). There were significant differences between the 2 groups in the angular and linear deviations at the implant apex and the shoulder and depth deviation. The accuracy of the muco-supported surgical guide was improved using the long anchor-guiding sleeve, thus providing more accurate flapless implant placement in edentulous models. However, model experiments do not always produce predictable and possible uncontrolled cause-and-effect outcomes under natural clinical conditions. Therefore, further in vivo investigations are required to determine whether the results of this study are consistent with clinical findings.


Subject(s)
Dental Implants , Mouth, Edentulous , Surgery, Computer-Assisted , Humans , Dental Implantation, Endosseous/methods , Surgery, Computer-Assisted/methods , Cone-Beam Computed Tomography , Computers , Computer-Aided Design , Imaging, Three-Dimensional
7.
J Korean Med Sci ; 36(36): e255, 2021 Sep 13.
Article in English | MEDLINE | ID: mdl-34519188

ABSTRACT

BACKGROUND: Since the declaration of the coronavirus disease 2019 (COVID-19) pandemic, COVID-19 has affected the responses of emergency medical service (EMS) systems to cases of out-of-hospital cardiac arrest (OHCA). The purpose of this study was to identify the impact of the COVID-19 pandemic on EMS responses to and outcomes of adult OHCA in an area of South Korea. METHODS: This was a retrospective observational study of adult OHCA patients attended by EMS providers comparing the EMS responses to and outcomes of adult OHCA during the COVID-19 pandemic to those during the pre-COVID-19 period. Propensity score matching was used to compare the survival rates, and logistic regression analysis was used to assess the impact of the COVID-19 pandemic on the survival of OHCA patients. RESULTS: A total of 891 patients in the pre-COVID-19 group and 1,063 patients in the COVID-19 group were included in the final analysis. During the COVID-19 period, the EMS call time was shifted to a later time period (16:00-24:00, P < 0.001), and the presence of an initial shockable rhythm was increased (pre-COVID-19 vs. COVID-19, 7.97% vs. 11.95%, P = 0.004). The number of tracheal intubations decreased (5.27% vs. 1.22%, P < 0.001), and the use of mechanical chest compression devices (30.53% vs. 44.59%, P < 0.001) and EMS response time (median [quartile 1-quartile 3], 7 [5-10] vs. 8 [6-11], P < 0.001) increased. After propensity score matching, the survival at admission rate (22.52% vs. 18.24%, P = 0.025), survival to discharge rate (7.77% vs. 5.52%, P = 0.056), and favorable neurological outcome (5.97% vs. 3.49%, P < 0.001) decreased. In the propensity score matching analysis of the impact of COVID-19, odds ratios of 0.768 (95% confidence interval [CI], 0.592-0.995) for survival at admission and 0.693 (95% CI, 0.446-1.077) for survival to discharge were found. CONCLUSION: During the COVID-19 period, there were significant changes in the EMS responses to OHCA. These changes are considered to be partly due to social distancing measures. As a result, the proportion of patients with an initial shockable rhythm in the COVID-19 period was greater than that in the pre-COVID-19 period, but the final survival rate and favorable neurological outcome were lower.


Subject(s)
COVID-19/epidemiology , Emergency Medical Services , Out-of-Hospital Cardiac Arrest/mortality , SARS-CoV-2 , Aged , Aged, 80 and over , Female , Humans , Logistic Models , Male , Middle Aged , Out-of-Hospital Cardiac Arrest/complications , Propensity Score , Republic of Korea/epidemiology , Retrospective Studies
8.
J Clin Med ; 11(1)2021 Dec 30.
Article in English | MEDLINE | ID: mdl-35011931

ABSTRACT

This study was to identify the effect of epinephrine on the survival of out-of-hospital cardiac arrest (OHCA) patients and changes in prehospital emergency medical services (EMSs) after the introduction of prehospital epinephrine use by EMS providers. This was a retrospective observational study comparing two groups (epinephrine group and norepinephrine group). We used propensity score matching of the two groups and identified the association between outcome variables regarding survival and epinephrine use, controlling for confounding factors. The epinephrine group was 339 patients of a total 1943 study population. The survival-to-discharge rate and OR (95% CI) of the epinephrine group were 5.0% (p = 0.215) and 0.72 (0.43-1.21) in the total patient population and 4.7% (p = 0.699) and 1.15 (0.55-2.43) in the 1:1 propensity-matched population. The epinephrine group received more mechanical chest compression and had longer EMS response times and scene times than the norepinephrine group. Mechanical chest compression was a negative prognostic factor for survival to discharge and favorable neurological outcomes in the epinephrine group. The introduction of prehospital epinephrine use in OHCA patients yielded no evidence of improvement in survival to discharge and favorable neurological outcomes and adversely affected the practice of EMS providers, exacerbating the factors negatively associated with survival from OHCA.

9.
J Oral Implantol ; 47(3): 236-241, 2021 Jun 01.
Article in English | MEDLINE | ID: mdl-32663266

ABSTRACT

This study aimed to evaluate bone regeneration within infected extraction sockets with bone defects using cone-beam computed tomography (CBCT) at a 1-year follow-up after implant placement in a prosthetically driven implant position. Forty-eight patients requiring premolar or molar tooth extraction due to bone defects caused by periodontal diseases were included. Vertical and horizontal bone volumes were assessed by overlapping the CBCT scan images with the full digital process. At 1-year post-extraction, a prosthetically-driven implant was planned using virtual implant planning software. At 1 year after extraction, CBCT revealed significant horizontal and vertical bone gains; an overall mean buccolingual bone width gain of 5.46 ± 2.87 mm, and an overall mean vertical bone gain of 0.27 ± 1.28 mm for the lingual bone plate level and 3.50 ± 1.81 mm for the buccal bone plate level were observed. Except for 4 (out of 48) sites, implants were virtually positioned in the center of the edentulous spaces. In summary, despite the dimensional changes after tooth extraction in compromised posterior sockets, there was sufficient bone for placing an implant using the prosthetically driven approach.


Subject(s)
Alveolar Bone Loss , Tooth Socket , Bone Regeneration , Cone-Beam Computed Tomography , Humans , Tooth Extraction
10.
J Prosthet Dent ; 125(2): 208-211, 2021 Feb.
Article in English | MEDLINE | ID: mdl-32147254

ABSTRACT

The all-on-4 implant concept has been used to overcome anatomic limitations and has been reported to have high success rates. A verification device is commonly used to transfer the position of the angled distal abutment accurately. This article describes a digital workflow for fabricating a verification device to position the angled distal abutment with a hexagon connection during computer-guided flapless surgery.


Subject(s)
Dental Implants , Dental Prosthesis, Implant-Supported , Dental Abutments , Dental Implant-Abutment Design , Workflow
11.
J Prosthet Dent ; 123(5): 675-679, 2020 May.
Article in English | MEDLINE | ID: mdl-31421891

ABSTRACT

Implant-supported overdentures can significantly increase function and satisfaction during the first year and can last for 5 to 10 years. The 2-implant-supported mandibular overdenture is recommended as a standard treatment for edentulous patients. In the recent years, studies have reported the use of digital complete dentures. However, as a modified technique for complete dentures, few studies have evaluated the use of digital techniques in the fabrication of overdentures. The purpose of this article was to introduce a digital workflow for fabricating overdentures by using information from the existing dentures.


Subject(s)
Dental Implants , Denture, Overlay , Dental Prosthesis, Implant-Supported , Denture, Complete, Lower , Humans , Mandible , Patient Satisfaction , Workflow
12.
J Oral Implantol ; 46(1): 3-12, 2020 Feb 01.
Article in English | MEDLINE | ID: mdl-31647687

ABSTRACT

The all-on-4 concept, which is used to rehabilitate edentulous patients, can present with mechanical complications such as screw loosening and fracture. The purpose of this study was to evaluate the stress patterns induced in the prosthetic screws by the different prosthetic screw and abutment designs in the all-on-4 concept using finite element analysis. Von Mises stress values on 6 groups of each screw type, including short and narrow screw, short abutment; short and wide screw, short abutment; long and wide screw, short abutment; short and narrow screw, long abutment; short and wide screw, long abutment; and long and wide screw, long abutment, were compared under a cantilever loading of 200 N that was applied on the farther posterior to the position of the connection between the distal implant and the metal framework. Posterior prosthetic screws showed higher stress values than anterior prosthetic screws. The stress values in posterior prosthetic screws decreased as the length and diameter increased. In conclusion, the long and wide screw design offers advantages in stress distribution when compared with the short and narrow design.


Subject(s)
Dental Abutments , Dental Implants , Bone Screws , Dental Prosthesis, Implant-Supported , Dental Stress Analysis , Finite Element Analysis , Humans , Stress, Mechanical
13.
Clin Exp Emerg Med ; 6(3): 218-225, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31571438

ABSTRACT

OBJECTIVE: This study was conducted to evaluate the concordance between the underlying causes of death (UCOD) on the death certificates written by three emergency physicians (EPs). We investigated errors on the death certificates committed by each EP. METHODS: This study included 106 patients issued a death certificate in the emergency department of an academic hospital. Three EPs reviewed the medical records retrospectively and completed 106 death certificates independently. The selection of the UCOD on the death certificates by each EP (EP-UCOD) was based on the general principle or selection rules. The gold standard UCOD (GS-UCOD) was determined for each patient by unanimous consent between three EPs. We also compared between the EP-UCOD and the GS-UCOD. In addition, we compared between UCODs of three EPs. The errors on the death certificates were investigated by each EP. RESULTS: The rates of concordance between EP-UCOD and the GS-UCOD were 86%, 81%, and 67% for EP-A, EP-B, and EP-C, respectively. The concordance rates between EP-A and EP-B were the highest overall percent agreement (0.783), and those between EP-A and EP-C were the lowest overall percent agreement (0.651). Although each EP had differences in the errors they committed, none of them listed the mode of dying as UCOD. CONCLUSION: This study confirmed that each EP wrote death certificates indicating different causes of death for the same decedents; however, the three EPs made fewer errors on the patients' death certificates compared with those reported in previous studies.

14.
Emerg Med Int ; 2019: 4198630, 2019.
Article in English | MEDLINE | ID: mdl-31485351

ABSTRACT

BACKGROUND: It is important to register anaphylaxis codes correctly to study the exact prevalence of anaphylaxis. The purpose of this study was to analyze the clinical characteristics and disease codes of inaccurately registered groups in pediatric anaphylaxis patients. METHODS: This study reviewed the medical records of all pediatric patients who presented to the university hospital emergency department over a 5-year period. Study subjects were divided into 2 groups: the accurate group, including those registered under anaphylaxis codes, and the inaccurate coding group, including those registered under other codes. RESULTS: From a total of 79,676 pediatric patients, 184 (0.23%) had anaphylaxis. Of these, 23 (12.5%) and 161 (87.5%) patients were classified to the accurate and inaccurate coding groups, respectively. Average age, time from symptom onset to emergency department presentation, past history of allergy, and penicillin and cephalosporin as causes of anaphylaxis differed between the 2 groups. Cardiovascular (39.1% vs. 5.6%, p=0.001) and respiratory symptoms (65.2% vs. 42.2%, p=0.038) manifested more frequently in the accurate group, while gastrointestinal symptoms (68.3% vs. 26.1%, p=0.001) were more frequently observed in the inaccurate coding group. Fluid administration (82.6% vs. 28.0%, p=0.001), steroid use (60.9% vs. 23.0%, p=0.001), and epinephrine use (65.2% vs. 13.0% p=0.001) were more common treatments for anaphylaxis in the emergency department in the accurate group. Anaphylaxis patients with cardiovascular symptoms, steroid use, and epinephrine use were more likely to be accurately registered with anaphylaxis disease codes. CONCLUSIONS: In the case of pediatric anaphylaxis, more patients were registered inaccurately under other allergy-related codes and simple symptom codes, rather than under anaphylaxis codes. Therefore, future research on anaphylaxis should consider inaccurately registered anaphylactic patients, as shown in this study.

15.
Clin Implant Dent Relat Res ; 21(5): 1054-1061, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31402583

ABSTRACT

BACKGROUND: Immediate loading has shown positive results for total, partial, or single edentulism. The effects of BMP-2 addition to graft materials on bone formation and implant stability in the early stages of healing have rarely been studied, especially in patients with severely atrophic maxillae. PURPOSE: To evaluate the effects of simultaneously placed immediate non-functional loaded implants and bone morphogenetic protein-2 (BMP-2)-loaded Bio-Oss collagen, on bone formation and implant stability during the early healing stages of patients with a severely atrophic posterior maxilla using crestal approach. MATERIALS AND METHODS: Thirty-three cases presenting posterior maxillary residual alveolar bone height of 1-3 mm were evaluated. Flapless crestal sinus augmentation surgery was performed using BMP-2-loaded Bio-Oss collagen, with non-functional implants immediately loaded after surgery. The bone height was assessed using preoperative and postoperative cone beam computed tomography (CBCT). Bone density of the sinus graft sites and implant stability (after 3 months) were evaluated using postoperative CBCT scans and Periotest, respectively. The periodontal parameters and marginal bone loss around the implant were checked after 37.3 months of final prosthesis. RESULTS: The survival rate of the implants was 100% and the gingiva around the implants remained healthy. All implants remained integrated, and all sinus grafts showed radiographic bone formation. The results indicated high level of bone density and good implant stability, showing minimal marginal bone loss after 37.3 months. CONCLUSION: This technique could be used in the posterior maxillary region exhibiting poor bone quantity.


Subject(s)
Alveolar Bone Loss , Dental Implants , Collagen , Dental Implantation, Endosseous , Dental Prosthesis Design , Dental Prosthesis, Implant-Supported , Dental Restoration Failure , Humans , Maxilla , Maxillary Sinus , Treatment Outcome
16.
J Prosthodont ; 28(6): 715-718, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31087422

ABSTRACT

A double-scan procedure is commonly performed in the process of fabricating an implant surgical template; however, this entails the disadvantage of recording 2 cone beam computed tomography (CBCT) scans requiring additional time, effort, and costs. The purpose of this article is to introduce a digital protocol to acquire adequate preoperative diagnostic information for a fully edentulous patient, using the existing complete denture with a metal framework, an intraoral scanner, and CBCT.


Subject(s)
Surgery, Computer-Assisted , Workflow , Computer-Aided Design , Cone-Beam Computed Tomography , Dental Implantation, Endosseous , Denture, Complete , Humans
17.
Comput Methods Biomech Biomed Engin ; 22(3): 251-258, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30773916

ABSTRACT

The purpose of this study is to measure the failure risk of a crown depending on the cusp angle. Three all-ceramic crown models consisting of CH (high incline), CM (middle incline), and CL (low incline) are designed. Stress is applied to the crown with Loading case-1 (top of cusp tip) and Loading case-2 (middle of cusp ridge) with the use of FEA software. In Loading case-1 and case-2, the CH showed the highest Maximum Principal Stress (MPS) while the CL showed the lowest MPS. The cusp angle is an influential factor affecting stress distribution in dental crowns.


Subject(s)
Crowns , Dental Prosthesis Design , Dental Stress Analysis , Finite Element Analysis , Humans , Stress, Mechanical
18.
J Prosthet Dent ; 121(5): 836-842, 2019 May.
Article in English | MEDLINE | ID: mdl-30598309

ABSTRACT

STATEMENT OF PROBLEM: Implant placement in the anterior regions is often challenging because of limited space and bone volume availability. PURPOSE: The purpose of this clinical study was to investigate the accuracy of computer-guided surgery with a long drill key to place implants in the anterior regions. MATERIAL AND METHODS: Computer-guided implant surgery was performed for 32 participants requiring implants in anterior regions. The procedure involved using a 12-mm-long drill key to guide the 2.0-mm-diameter drill. Deviations between the planned and actual implant positions were evaluated by using cone beam computed tomography (CBCT) scans obtained before and after surgery. A t test was used for comparisons between the planned and placed implants and to determine the influence of the arch (maxilla/mandible) and time (immediate/delayed) on accuracy. RESULTS: A total of 40 implants (20 implants in the maxilla and 20 implants in the mandible) were placed. The mean linear deviation was 0.46 mm (range, 0 to 1.15 mm) for the implant shoulder and 0.67 mm (range, 0.14 to 1.19 mm) for the implant apex. The mean angular deviation was 1.40 degrees (range, 0.30 to 2.57 degrees). The mean depth deviation was 0.15 mm (range, 0.10 to 0.82 mm). CONCLUSIONS: This clinical study showed that the accuracy of computer-guided implant placement may be enhanced by using a long drill key and may thus enable more accurate implant placement in anterior regions.


Subject(s)
Dental Implants , Surgery, Computer-Assisted , Computer-Aided Design , Cone-Beam Computed Tomography , Dental Implantation, Endosseous , Mandible , Maxilla
19.
J Prosthodont ; 28(2): e519-e523, 2019 Feb.
Article in English | MEDLINE | ID: mdl-29522269

ABSTRACT

Few studies have reported the application of digital technology for the process of impression and interocclusal recordings in edentulous patients. This article describes a digitizing system for generating digital edentulous models with a jaw relationship by taking direct digital impressions and a virtual bite registration using intraoral digital scanning. A specialized scan retractor was used to make digital impressions of edentulous jaws in patients' mouths using an intraoral scanner. Virtual bite registration was obtained with optical scanning of the buccal surfaces of both jaws at the occlusal vertical dimension. The registration was then used as a reference for aligning both jaws. Digital edentulous models that include the jaw relationship would be clinically beneficial for the fabrication of complete dentures in edentulous patients.


Subject(s)
Dental Impression Technique , Denture Design , Image Processing, Computer-Assisted/methods , Jaw Relation Record/methods , Computer-Aided Design , Dental Impression Materials , Humans , Jaw, Edentulous/rehabilitation , Models, Dental , Software
20.
J Prosthet Dent ; 121(1): 26-31, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29961624

ABSTRACT

The conversion of a denture into an interim implant-supported, screw-retained restoration has become the standard method for immediate interim restoration in patients with complete edentulism. The most critical steps of the denture conversion process are the creation of appropriate denture access holes to prevent displacement of the denture by the interim cylinders and removal of the denture flanges to facilitate both good esthetics and accessibility for oral hygiene after the denture is connected to the interim cylinders. This article presents a digital technique for designing and fabricating an interim implant-supported, fixed prosthesis for edentulous patients. The interim prosthesis has cylinder access holes that are digitally prefabricated and a denture flange part that is designed to be easily sectioned. This technique facilitates more straightforward and efficient immediate restoration for edentulous patients after implant placement.


Subject(s)
Dental Implants , Dental Prosthesis Design , Dental Prosthesis, Implant-Supported/methods , Denture, Complete, Immediate , Immediate Dental Implant Loading , Jaw, Edentulous/surgery , Acrylic Resins , Computer-Aided Design , Denture Bases , Denture Design/methods , Denture, Complete, Lower , Humans , Mandible/pathology , Mandible/surgery , Models, Dental , Mouth, Edentulous/surgery , Printing, Three-Dimensional
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