Full mouth rehabilitation using 3D printed crowns and implant assisted removable partial denture for a crossed occlusion: a case report / 대한치과보철학회지

With the recent development of computer-aided design-computer-aided manufacturing technology and 3D printing technology, and the introduction of various digital techniques, the accuracy and efficiency of top-down definitive prosthetic restoration are increasing. In this clinical case, stable occlusion support was obtained through the placement of a total of 9 maxillary and mandibular posterior implants in patient with anterior-posterior crossed occlusion. The edentulous area of the maxillary anterior teeth, which showed a tendency of high resorption of the residual alveolar bone, was restored with a Kennedy Class IV implant assisted removable partial denture to restore soft tissue esthetics. Computed tomography guided surgery was used to place implants in the planned position, double scan technique was used to reflect the stabilized occlusion in the interim restoration stage to the definitive prostheses, and metal 3D printing was used to manufacture the coping and framework. This clinical case reports that efficient and predictable top-down full mouth rehabilitation was achieved using various digital technologies and techniques.

Effect of hemispherical dimples at titanium implant abutments for the retention of cemented crowns

PURPOSE@#. The aim of this study was to assess the effect of hemispherical dimple structures on the retention of cobalt–chromium (Co–Cr) crowns cemented to titanium abutments, with different heights and numbers of dimples on the axial walls. @*MATERIALS AND METHODS@#. 3.0-mm and 6.0-mm abutments (N = 180) and Co-Cr crowns were prepared. The experimental groups were divided into two and four dimple groups. The crowns were cemented by TempBond and PANAVIA F 2.0 cements. The retention forces were measured after thermal treatments. A twoway Analysis of Variance (ANOVA) and post-hoc Tukey HSD test were conducted to analyze change in retention forces by use of dimples between groups, as well as t test for the effect of abutment height change (α = .05). @*RESULTS@#. Results of the two-way ANOVA showed a statistically significant difference in retention force due to the use of dimples, regardless of the types of cements used (P < .001). A significantly higher mean retention forces were observed in the groups with dimples than in the control group, using the post hoc Tukey HSD test (P < .001). @*Results@#of t test displayed a statistically significant increase in the retention force with 6.0-mm abutments compared with 3.0-mm abutments (P < .001). The groups without dimples revealed adhesive failure of cements, while the groups with dimples showed mixed failure of cements. @*CONCLUSION@#. Use of hemispherical dimples was effective for increasing retention forces of cemented crowns.

Comparative study of surface characteristics and shear bond strength of 3D printed and milled 4Y-TZP / 대한치과재료학회지

This study aimed to compare the surface characteristics and the shear bond strength of veneering porcelain of 3D printed 4Y-TZP with milled 4Y-TZP. Thirty disks with 10 mm diameter and 1.2 mm thickness were fabricated. Fifteen were fabricated by 3D printing (Experimental group), and another 15 by milling (Control group). In each group, five were assigned to surface analysis. Surface roughness was measured using a confocal laser microscope. Surface energy was calculated by measuring the contact angles of water and diiodo-methane with a drop-shape analyzer. Another ten specimens were used to evaluate the shear bonding strength of veneering porcelain on the surface of 4Y-TZP. The surface of 3D-printed 4Y-TZP was very smooth, and the surface roughness (Ra, Rq) was significantly lower than that of milled 4Y-TZP (p<0.001). 3D-printed 4Y-TZP showed low wettability compared with milled 4Y-TZP, i.e., the water contact angle was significantly high (p=0.008), and the surface free energy was low (p=0.008). The shear bond strength to veneered porcelain of 3D printed 4Y-TZP was significantly lower than that of milled 4Y-TZP (p<0.001). The surface characteristics of 4Y-TZP were quite different by the manufacturing process. The smooth surface and low wettability of 3D-printed 4Y-TZP could affect its low shear bonding strength to veneering porcelain.

Influence of finish line design on the marginal fit of nonprecious metal alloy coping fabricated by 3D printing, milling and casting using CAD-CAM / 대한치과보철학회지

Purpose@#The purpose of this study was to examine the correlation between the finish line designs and the marginal adaptation of nonprecious metal alloy coping produced by different digital manufacturing methods. @*Materials and methods@#Nonprecious metal alloy copings were made respectively from each master model with three different methods; SLS, milling and casting by computer aided design and computer aided manufacturing (CAD-CAM). Twelve copings were made by each method resulting in 72 copings in total. The measurement was conducted at 40 determined reference points along the circumferential margin with the confocal laser scanning microscope at magnification ×150. @*Results@#Mean values of marginal gap of laser sintered copings were 11.8 ± 7.4 μm for deep chamfer margin and 6.3 ± 3.5 μm for rounded shoulder margin and the difference between them was statistically significant (P < .0001). Mean values of marginal gap of casted copings were 18.8 ± 20.2 μm for deep chamfer margin and 33 ± 20.5 μm for rounded shoulder margin and the difference between them was significant (P = .0004). Conclusion: Within the limitation of this study, the following conclusions were drawn. 1. The variation of finish line design influences the marginal adaptation of laser sintered metal coping and casted metal coping. 2. Laser sintered copings with rounded shoulder margin had better marginal fit than deep chamfer margin. 3. Casted copings with deep chamfer margin had better marginal fit than rounded shoulder margin. 4. According to the manufacturing method, SLS system showed the best marginal fit among three different methods. Casting and milling method followed that in order.

Full-mouth rehabilitation of a patient with loss of posterior support and collapsed occlusion utilizing dental CAD-CAM system / 대한치과보철학회지

Without proper treatment on the multiple tooth missing area, the lack of posterior support and the supra-eruption of the teeth cause many severe complications of occlusion, vertical dimension and masticatory function. This report is a case of full-mouth rehabilitation of a patient with loss of posterior support and collapsed occlusion due to missing teeth area left untreated for a long time. The patient who is 68-year old male patient had some teeth fallen out while removing his old maxillary denture and was complaining about pain in the region of anterior teeth due to traumatic contact. The vertical dimension was corrected by 4 mm from the top cervical point of the canine through various evaluations and the edentulous area was treated with the implant fixed prostheses through computer guided implant surgery based on the diagnosis and treatment plan for definitive prostheses supported by computed tomography (CT) data analysis and CAD-CAM (Computer-aided design/computer-aided manufacturing) technique. After full mouth rehabilitation, the patient was very satisfied with remarkable improvements in mastication, function, and aesthetics.

Full mouth rehabilitation of the patient with severely worn dentition and limited vertical dimension / 대한치과보철학회지

Severely worn dentition causes various complications such as loss of tooth structure, discoloration, pulp complications and loss of function and aesthetics. In this case, the patient showed particularly severe attrition in the anterior teeth and lack of space for restoration. The amount of vertical dimension was determined based on the diagnostic wax up, and the patient’s adaptation was evaluated by using a removable occlusal splint for 6 weeks. Thereafter, the coordination of the muscular nervous system, aesthetics, temporomandibular joint were re-evaluated for 3 months by restoring the fixed provisional restoration. Through the above treatment process, the final restoration was completed with full mouth fixed prosthesis using monolithic zirconia, and functionally and aesthetically stable results were obtained.

Clinical and radiographic evaluations of implants as surveyed crowns for Class I removable partial dentures: A retrospective study

PURPOSE@#. The purpose of this study was to evaluate survival rates and marginal bone loss (MBL) of implants in IC-RPDs. @*MATERIALS AND METHODS@#. Seventy implants were placed and used as surveyed crowns in 30 RPDs. The survival rates and MBL around implants based on multiple variables, e.g., position, sex, age, opposing dentitions, splinting, type of used retainer, and first year bone loss, were analyzed. Patient reported outcome measures (PROMs) regarding functional/ esthetic improvement after IC-RPD treatment, and complications were also inspected. @*RESULTS@#. The 100% implant survival rates were observed, and 60 of those implants showed MBL levels less than 1.5 mm. No significant differences in MBL of implants were observed between implant positions (maxilla vs. mandible; P = .341) and type of used retainers (P = .630). The implant MBL of greater than 0.5 mm at 1 year showed significantly higher MBL after that (P < .001). Splinted implant surveyed crowns showed lower MBL in the maxilla (splinted vs. nonsplinted; P = .037). There were significant esthetic/functional improvements observed after treatment, but there were no significant differences in esthetic results based on implant position (maxilla vs. mandible). Implants in mandible showed significantly greater improvement in function than implants in the maxilla (P = .002). Prosthetic complication of IC-RPD was not observed frequently.However, 2 abutment teeth among 60 were failed. The bone loss of abutment teeth was lower than MBL of implants in IC-RPDs (P = .001). @*CONCLUSION@#. Class I RPD connected to residual teeth and strategically positioned implants as surveyed crowns can be a viable treatment modality.

Digital duplication of provisional prosthesis to fabricate definitive prosthesis for full mouth rehabilitation using double scan technique / 대한치과보철학회지

Using computer-aided design and manufacturing technique improve quality of treatment in many aspect. This case reports the complete mouth rehabilitation of a patient with amelogenesis imperfecta utilizing digital technology. Clinical examination revealed loss of mastication due to insufficient occlusal stop, missing teeth, interdental spacing due to microdontia, insufficient overbite, and etc. Full veneer crowns for teeth were selected, followed by a fixed partial denture and implant placement was done using CAD-CAM guide template with bone graft for partially edentulous space. Definitive restorations were duplicated by double scanning provisional restorations and successfully delivered to the patient. These full mouth rehabilitation procedures resulted in satisfactory outcomes for the patient functionally and aesthetically.

Effects of anaerobic sealing agents on preload maintenance ofscrew-retained implant prosthesis with surface of screws / 대한치과보철학회지

Purpose@#The purpose of this study was to evaluate the preload maintenance of the retaining screw when using anaerobic sealing agents in implant fixture and abutmentcomponents. Specifically, the study examines the effects of anaerobic sealing agents on different types of screws. Materials and methods: External hexagon implants madeof titanium and anti-rotational abutments were used. Titanium abutment screws and ebony abutment screws from the same manufacturer were used. The experiment wasdivided into four groups (n = 10 in each group). In the control group, no sealing agent was used at the implant fixture and abutment screw interface. All abutment screws weretightened according to the manufacturer’s recommended torque (30 N.cm). After 24 hours, the removal torque (detorque) of each screw was measured using a digital torquegauge device. The data were analyzed by two-way ANOVA test according to normality distribution satisfaction. Results: Looking at the results for each group, titaniumscrews and no treatment showed detorque values of 20.3 ± 1.6 N.cm. titanium screws and applied anaerobic sealing agent showed detorque values of 32.4 ± 6.7 N.cm. Ebonyscrews and no treatment showed detorque values of 20.2 ± 1.5 N.cm. ebony screws and applied anaerobic sealing agent showed detorque values of 30.4 ± 4.5 N.cm. @*Conclusion@#The detorque value was higher in the case of using anaerobic sealing agents in both the titanium screw and ebony screw groups. But there was no differencebetween the two screws. (J Korean Acad Prosthodont 2020;58:103-9)

Survival rate and clinical evaluation of the implants in implant assisted removable partialdentures: surveyed crown and overdenture

PURPOSE@#. The purpose of this study was to investigate survival rates of the implants used in implant assisted removable partial dentures (IARPDs). @*MATERIALS AND METHODS@#. The study was conducted on 21 patients who were treated with IARPDs. The mean follow-up period for IARPD patients ranged from 12 to 185 months (mean 47.9 months). A total of 58 implants were used for IARPDs in two different modalities: 41 for surveyed crowns and 17 for overdentures. The survival of implants was determined by clinical and radiographic evaluations considering relevant factors: location, RPD classification, opposing dentition, splinting, and implant diameter. @*RESULTS@#The survival rate of total 58 implants was 93.1%: 95.1% for implants supporting surveyed crowns and 88.2% for implants used in overdentures. Considering only the implants supporting surveyed crown, regular diameter implants showed a higher survival rate than narrow or wide diameter implants. @*CONCLUSION@#The survival rate of the implants used in IARPDs was 93.1% (surveyed crown: 95.1%, overdenture: 88.2%).

Comparison of CAD/CAM abutment and prefabricated abutment in Morse taper internal type implant after cyclic loading: Axial displacement, removal torque, and tensile removal force

PURPOSE: The purpose of this study was to compare computer-aided design/computer-aided manufacturing (CAD/CAM) abutment and prefabricated abutment in Morse taper internal connection type implants after cyclic loading.MATERIALS AND METHODS: The study was conducted with internal type implants of two different manufacturers (Group Os, De). Fourteen assemblies were prepared for each manufacturer group and divided into 2 groups (n=7): prefabricated abutments (Os-P, De-P) and CAD/CAM abutments (Os-C, De-C). The amount of axial displacement and the removal torque values (RTVs) were measured before and after cyclic loading (10⁶ cycles, 3 Hz with 150 N), and the tensile removal force to dislodge the abutments was measured after cyclic loading. A repeated measures ANOVA and a pattern analysis based on the logarithmic regression model were conducted to evaluate the effect of cyclic loading on the axial displacement. The Wilcoxon signed-rank test and the Mann-Whitney test was conducted for comparison of RTV reduction% and tensile removal forces.RESULTS: There was no significant difference between CAD/CAM abutments and prefabricated abutments in axial displacement and tensile removal force; however, significantly greater RTV reduction% after cyclic loading was observed in CAD/CAM abutments. The correlation among the axial displacement, the RTV, and the tensile removal force was not significant.CONCLUSION: The use of CAD/CAM abutment did not significantly affect the amount of axial displacement and tensile removal force, but presented a significantly greater removal torque reduction% than prefabricated abutments. The connection stability due to the friction at the abutment-implant interface of CAD/CAM abutments may not be different from prefabricated abutment.

Inhibition of Osteoclast differentiation based on precipitation time of titanium surfaces immersed in modified simulated body fluid / 대한치과보철학회지

PURPOSE: The purpose of this study is to investigate the changes of osteoclast differentiation inhibition according to the period of precipitation when titanium disks were immersed in Modified simulated body fluid (mSBF). MATERIALS AND METHODS: Titanium alloy (Ti grade III) disks with machined surfaces and anodized surfaces were immersed in distilled water and mSBF, respectively. The immersion periods were 7 days, 14 days, 21 days and 28 days, and the control group was immersed in distilled water for each period. RAW 264.7 cells capable of differentiating into osteoclasts were used to measure the number of adherent cells, the measurement of TRAP activity, and the expression pattern of NFATc1 by western blotting. RESULTS: The degree of inhibition of osteoclast differentiation was found to be statistically significant when the disks were immersed in mSBF for more than 14 days on both machined surfaces and anodized surfaces. There was no correlation between immersion time and cell attachment. When the disks were immersed for more than 14 days, TRAP activity was decreased and NFATc1 expression was inhibited. Futhermore, the decrease in TRAP activity and the inhibition of NFATc1 expression remained unchanged. CONCLUSION: Immersion of titanium disks in mSBF for more than 14 days can prevent RAW 264.7 cells from differentiating into osteoclasts. Inhibition activity does not change even if the immersion period is for more than 14 days.

Comparison of Flexural Strength of Three-Dimensional Printed Three-Unit Provisional Fixed Dental Prostheses according to Build Directions

PURPOSE: The aim of this study was to compare the flexural strength of provisional fixed dental prostheses which was three-dimensional (3D) printed by several build directions. MATERIALS AND METHODS: A metal jig with two abutment teeth and pontic space in the middle was fabricated. This jig was scanned with a desktop scanner and provisional restoration was designed on dental computer-aided design program. On the preprocessing software, the build angles of the restorations were arranged at 0°, 30°, 45°, 60°, and 90° and support was added and resultant structure was sliced to a thickness of 100 µm. Processed restorations were printed with digital light processing type 3D printer using poly methyl meta acrylate-based resin. After washing and post-curing, compressive loading was applied at a speed of 1 mm/min on a metal jig fixed to a universal testing machine. The maximum pressure at which fracture occurred was measured. For the statistical analysis, build direction was set as the independent variable and fracture strength as the dependent variable. One-way analysis of variance and Tukey's post hoc analysis was conducted to compare fracture strength among groups (α=0.05). RESULT: The mean flexural strength of provisional restoration 3D printed with the build direction of 0° was 1,053±168 N; it was 1,183±188 N at 30°, 1,178±81 N at 45°, 1,166±133 N at 60°, and 949±170 N at 90°. The group with a build direction of 90° showed significantly lower flexural strength than other groups (P<0.05). The flexural strength was significantly higher when the build direction was 30° than when it was 90° (P<0.01). CONCLUSION: Among the build directions 0°, 30°, 45°, 60°, and 90° set for 3D printing of fixed dental prosthesis, an orientation of 30° is recommended as an effective build direction for 3D printing.

Characterization and Differentiation of Circulating Blood Mesenchymal Stem Cells and the Role of Phosphatidylinositol 3-Kinase in Modulating the Adhesion

Bone marrow mesenchymal stem cells (BM MSCs) can differentiate into multi-lineage tissues. However, obtaining BM MSCs by aspiration is difficult and can be painful; therefore peripheral blood (PB) MSCs might provide an easier alternative for clinical applications. Here, we show that circulating PB MSCs proliferate as efficiently as BM MSCs in the presence of extracellular matrix (ECM) and that differentiation potential into osteoblast in vitro and in vivo. Both BM MSCs and PB MSCs developed into new bone when subcutaneously transplanted into immune-compromised mice using hydroxyapatite/tricalcium phosphate as a carrier. Furthermore, LY294002 and Wortmannin blocked mesenchymal stem cell attachment in a dose-dependent manner, suggesting a role of phosphatidylinositol 3-kinase in MSC attachment. Our data showed that the growth of PB MSCs could be regulated by interaction with the ECM and that these cells could differentiate into osteoblasts, suggesting their potential for clinical applications.

Full mouth rehabilitation using orthodontic treatment and implants in patient with collapsed occlusion: A case report / 대한치과보철학회지

The distance between the natural teeth and the implants is an important factor in preserving the periodontal tissues and esthetics. And abnormal positional displacement and tilting of the teeth during restorative procedure may require intentional root canal treatment and may affect masticatory function. This report is to present a successful full mouth rehabilitation of a patient with uneven dentition and collapsed occlusion using orthodontic and implant treatment. The patient had no symptoms or discomfort of temporomandibular joint disorder such as pain or sound. The orthodontic treatment was continued until implant provisional prosthesis delivery. And the vertical height of occlusion was elevated 2mm on anterior basis for anterior teeth protection and esthetics. After the orthodontic treatment, the implant abutments and natural teeth were finally restored with porcelain-fused-to-metal crowns and bridges. Satisfactory function and esthetic outcomes are observed after 6months of follow up.

Prosthetic rehabilitation of soft palate resection edentulous patient with maxillary obturator / 대한치과보철학회지

This report is a case of 76-year old male patient who had difficulty in swallowing, pronunciation and suffered regurgitation of food. The patient lacks uvula and both tonsils, had short palatoglossal arch and soft palate, as well as defective left palatopharyngeal arch. The height and width of the soft palate defect were measured by reconstructing the Computed Tomography (CT) image in three dimensions. Phonation and soft palate obstructing ability were examined by nasometry and nasal endoscopy. Evaluations on phonetics and swallowing were done and improvements were shown. The patient was satisfied with the results of treatment.

Cellular Response of Anodized Titanium Surface by Poly(Lactide-co-Glycolide)/Bone Morphogenic Protein-2

BACKGROUND: The purpose of this study is to examine physical characteristics of and initial biological properties to anodized titanium treated with poly(D,L-lactide-co-glycolide) (PLG) mixed with recombinant human bone morphogenic protein-2 (rhBMP-2). METHODS: Titanium specimens were prepared in groups of four as follows: group NC was anodized under 300 V as control; group PC was anodized then dropped and dried with solution 0.02 ml PLG; group D was anodized then dropped and dried with solution 0.02 ml PLG/rhBMP-2 (3.75 µg per disc); and group E was anodized then coated with 0.02 ml PLG/rhBMP-2 (3.75 µg per disc) by electrospray. Human osteoblastic-like sarcoma cells were cultured. Cell proliferation and alkaline phosphatase (ALP) activity test were carried out. Runx-2 gene was investigated by the reverse transcription-polymerase chain reaction. Immunofluorescence outcome of osteogenic proteins was observed. RESULTS: After 3 days, there were significantly higher proliferations compared rhBMP-2 loaded titanium discs with rhBMP-2 unloaded discs. The ALPase activity on rhBMP-2 loaded titanium discs was significantly higher than in rhBMP-2 unloaded discs. The expression level of Runx2 mRNA presented the highest on the PLG/rhBMP-2-coated surface. CONCLUSION: PLG polymers mixed with rhBMP-2 might improve proliferation, differentiation and osteogenic protein formation of cells on the anodized titanium.

Denture wearers' recognition for their oral health status, denture cleansing methods, and insurance health system / 대한치과보철학회지

PURPOSE: The aim of the present investigation was to understand the incidence, prevalence of denture stomatitis in denture wearers, who were over 60 years old, and use the results for a fundamental data to promote public awareness about denture stomatitis and its education tools. MATERIALS AND METHODS: From August 21 to September 8 2017, 500 denture wearers, who were more than 60 years old in Seoul and 4 other metropolitan cities (Busan, Daegu, Gwangju, and Daejeon), received questionnaires. The questionnaires included denture wearers' demographic distributions, specific dental treatment experiences, discomforts with current dentures, their oral health conditions, and the method of denture cleansing. RESULTS: Thirty-two percent of 500 denture wearers responded that they have healthy oral conditions. Two hundred and eight respondents (41.6%) were aware of denture stomatitis. Only 131 (26.2%) were informed about the removable denture covered by national health insurance and 327 (65.4%) of denture wearers were using the improper denture cleansing methods. CONCLUSION: A large number of denture wearers still do not recognize the importance of proper treatment for denture stomatitis, insurance covered denture treatments, and adequate denture cleansing methods.

Full mouth rehabilitation of the elderly patient on anticoagulant medication with loss of vertical dimension due to severely worn dentition / 대한치과보철학회지

Severe dental attrition causes pathological changes of the tooth, collapsed occlusion, and functional and aesthetic complications and can also result in a decrease in occlusal vertical dimension. Before increasing the vertical dimension with full-mouth rehabilitation, it is important to determine the amount of vertical dimension through accurate diagnosis. In this case, a 77 year old elderly male patient on anticoagulant medication with generalized attrition and fracture of teeth was treated with full-mouth rehabilitation in order to recover vertical dimension and aesthetics. Accurate clinical and radiographic examination, diagnostic, wax-up, and occlusal vertical dimension evaluation were step by step performed considering pre-medical history and old age. Patient adaptability was evaluated using an occlusal splint and interim restoration. After 3 months of stabilization with interim restoration, definitive prostheses were fabricated. Satisfactory functional and esthetic outcomes are observed after 6 months of follow up.

Comparison of implant component fractures in external and internal type: A 12-year retrospective study

PURPOSE: The aim of this study was to compare the fracture of implant component behavior of external and internal type of implants to suggest directions for successful implant treatment. MATERIALS AND METHODS: Data were collected from the clinical records of all patients who received WARANTEC implants at Seoul National University Dental Hospital from February 2002 to January 2014 for 12 years. Total number of implants was 1,289 and an average of 3.2 implants was installed per patient. Information about abutment connection type, implant locations, platform sizes was collected with presence of implant component fractures and their managements. SPSS statistics software (version 24.0, IBM) was used for the statistical analysis. RESULTS: Overall fracture was significantly more frequent in internal type. The most frequently fractured component was abutment in internal type implants, and screw fracture occurred most frequently in external type. Analyzing by fractured components, screw fracture was the most frequent in the maxillary anterior region and the most abutment fracture occurred in the maxillary posterior region and screw fractures occurred more frequently in NP (narrow platform) and abutment fractures occurred more frequently in RP (regular platform). CONCLUSION: In external type, screw fracture occurred most frequently, especially in the maxillary anterior region, and in internal type, abutment fracture occurred frequently in the posterior region. placement of an external type implant rather than an internal type is recommended for the posterior region where abutment fractures frequently occur.