Full mouth rehabilitation of edentulous patient with fixed implant prosthesis

There are various treatment options such as conventional complete denture, hybrid prosthesis and implant-supported fixed prosthesis for fully edentulous patients. In case of implant-supported fixed prosthesis, compared to removable prosthesis, it is difficult to place the implant in the correct position considering the anatomical contours of the final prosthesis. In this case, a full mouth rehabilitation with implant-supported fixed prosthesis was performed for a patient who required extraction of all remaining teeth due to dental caries and chronic periodontitis. In the implant placement stage, the implant was placed in the desired position using a surgical guide fabricated considering the anatomical contours of the final prosthesis, and the function and esthetics were evaluated through correction and re-fabrication of the fixed provisional restoration. A final restoration of porcelain fused to gold prosthesis was delivered to the patient based on the provisional restoration. To cope with complications such as loosening of screws and fracture of porcelain, a screw-retained type prosthesis was fabricated for the posterior part and a screw-cement-retained type prosthesis for the anterior part. As a result, the patient showed an improved prognosis in terms of functional and esthetics after the final prosthesis was delivered.

Color stability of three dimensional-printed denture teeth exposed to various colorants / 대한치과보철학회지

PURPOSE: This study evaluated color stability of Dentca 3D-printed denture teeth, in comparison to color stabilities of four conventional types of denture teeth, upon being immersed in various colorants.MATERIALS AND METHODS: Four types of conventional prefabricated denture teeth (Surpass, GC, Artic 6, Heraeus Kulzer, Premium 6, Heraeus Kulzer, Preference, Candulor), 3D-printed denture teeth (Dentca); and Z250 (Filtek Z250, 3M ESPE) were prepared for testing. The samples were immersed in erythrosine 3%, coffee, cola, and distilled water (DW) at 37℃. Color change (ΔE) was measured by spectrophotometer before immersion and at 7, 14, and 21 days after immersion. One-way analysis of variance was performed along with Tukey's honestly significant difference multiple comparisons test (P<.05).RESULTS: No great difference was observed between the color change of Dentca denture teeth and that of conventional denture teeth in most cases (P>.05). The color change of Dentca denture teeth immersed in erythrosine 3% was greater than that of Surpass (ΔE = 0.67 ± 0.25) after 1 week; Artic 6 (ΔE = 1.44 ± 0.38) and Premium 6 (ΔE = 1.69 ± 0.35) after 2 weeks; and Surpass (ΔE = 1.79 ± 0.49), Artic 6 (ΔE = 2.07 ± 0.21), Premium 6 (ΔE = 2.03 ± 0.75), and Preference (ΔE = 2.01 ± 0.75) after 3 weeks (P<.05).CONCLUSION: A color change was observed in Dentca denture teeth when immersed in some colorants; however, the maximum value of ΔE for Dentca denture teeth was within the clinically acceptable range.

Three-dimensional printed complete denture fabrication using the scan data from the conventional denture-making process

Recently three-dimensional (3D) printed complete dentures are becoming more widely recognized as one of the treatment options for the edentulous patients. Korean National Healthcare, however, has not yet approved the application of the 3D printed dentures, and in the cases where the dentures should be refabricated, the conventional fabrication process needs to be entirely repeated.However, during the conventional process, the digital scan data of some key steps could be easily obtained. In this clinical case, using these data, a new pair of 3D printed dentures that improved the limitations of the first conventional dentures were successfully fabricated.

Three-dimensional printed complete denture fabrication using the scan data from the conventional denture-making process

Recently three-dimensional (3D) printed complete dentures are becoming more widely recognized as one of the treatment options for the edentulous patients. Korean National Healthcare, however, has not yet approved the application of the 3D printed dentures, and in the cases where the dentures should be refabricated, the conventional fabrication process needs to be entirely repeated.However, during the conventional process, the digital scan data of some key steps could be easily obtained. In this clinical case, using these data, a new pair of 3D printed dentures that improved the limitations of the first conventional dentures were successfully fabricated.

Full mouth rehabilitation for a Parkinson's diseases patient with chronic periodontitis: a case report

Parkinson's disease is a neurological disorder characterized by tremor, bradykinesia, akinesia, postural instability, and muscular rigidity, which is caused by the depletion of neurotransmitters such as dopamine. Cooperative dental treatment is more challenging because of tremor of Parkinson's disease. In this case, a 47-year-old Parkinson's disease patient with chronic periodontitis was treated with full-mouth rehabilitation using conventional fixed prostheses and implant fixed partial denture, which attained satisfactory outcomes functionally and esthetically. Short term periodic follow-ups will be needed with consideration for the characteristics of Parkinson's disease such as decreased manual dexterity.

Screw loosening and changes in removal torque relative to abutment screw length in a dental implant with external abutment connection after oblique cyclic loading

PURPOSE: This study investigated the effects of abutment screw lengths on screw loosening and removal torque in external connection implants after oblique cyclic loading. MATERIALS AND METHODS: External connection implants were secured with abutment screws to straight abutments. The abutment-implant assemblies were classified into seven groups based on the abutment screw length, with each group consisting of five assemblies. A cyclic load of 300 N was applied at a 30° angle to the loading axis until one million cycles were achieved. Removal torque values (RTVs) before and after loading, and RTV differences were evaluated. The measured values were analyzed using repeated measures of analysis of variance with the Student-Newman-Keuls multiple comparisons. RESULTS: All assemblies survived the oblique cyclic loading test without screw loosening. There was a significant decrease in the RTVs throughout the observed abutment screw lengths when the abutment-implant assemblies were loaded repeatedly (P < .001). However, the abutment screw length did not show significant difference on the RTVs before and after the experiment when the abutment screw length ranged from 1.4 to 3.8 mm (P=.647). CONCLUSION: Within the limit of this experiment, our results indicate that the abutment screw length did not significantly affect RTV differences after oblique cyclic loading when a minimum length of 1.4 mm (3.5 threads) was engaged. These findings suggest that short abutment screws may yield stable clinical outcomes comparable to long screws in terms of load resistance.

Prosthetic rehabilitation using an obturator in a fully edentulous patient who had partial maxillectomy

Prosthetic rehabilitation of an edentulous patient who has a maxillary defect is difficult to achieve for many clinicians. The maxillary defect causes leakage of air during pronunciation and compromises denture stability, support and retention by reducing denture-bearing area and breaking peripheral seal. In these patients, the sizes and shapes of defects are very important factors which attribute to prognosis of maxillary obturators. This case report shows the prosthetic rehabilitation of the patient who had maxillectomy on the right maxillary sinus because of squamous cell carcinoma. The patient had a stepwise treatment protocol which started with pre-operative dental examination and followed by surgical, interim and definitive obturation phase. In this case, an acceptable level of retention could be obtained due to well-defined static defects and the preserved premaxillae and the patient was satisfied with the result of the treatment in the aspect of function and esthetics.

Prosthetic rehabilitation of a fully edentulous patient after maxillectomy: A case report / 대한치과보철학회지

Most patients with acquired maxillary surgical defects have difficulties such as functional impairments of mastication, speech, and deglutition as well as various degrees of facial deformity. The purpose of a prosthetic approach is to restore function and appearance with an obturator as normal as possible. This goal can be achieved when there is thoughful preoperative communication between a prosthodontist and a surgeon regarding a rehabilitation. In this case report, prosthetic rehabilitation was planned before the surgery for the patient diagnosed with squamous cell carcinoma in the right maxillary sinus with careful oral examination. Four months after maxillectomy, a definitive obturator was fabricated following the surgical and interim obturation phase. The objective of this case report is to describe the satisfactory results of the patient with improved rehabilitation of mastication, speech, deglutition, and appearance.

The effect of a titanium socket with a zirconia abutment on screw loosening after thermocycling in an internally connected implant: a preliminary study

PURPOSE: The aim of this study was to investigate the effects of a titanium component for the zirconia abutment in the internal connection implant system on screw loosening under thermocycling conditions. MATERIALS AND METHODS: Internal connection titanium abutments and external connection zirconia abutments with titanium sockets were connected respectively to screw-shaped internal connection type titanium implants with 30 Ncm tightening. These implant-screw-abutment assemblies were divided into two groups of five specimens each; titanium abutments as control and zirconia abutments with titanium sockets as experimental group. The specimens were subjected to 2,000 thermocycles in water baths at 5℃ and 55℃, with 60 seconds of immersion at each temperature. The removal torque values (RTVs) of the abutment screws of the specimen were measured before and after thermocycling. RTVs pre- and post-thermocycling were investigated in statistics. RESULTS: There was not screw loosening identified by tactile and visual inspection in any of the specimens during or after thermocycling. The mean RTV difference for the control group and the experimental group were -1.34 ± 2.53 Ncm and -1.26 ± 2.06 Ncm, respectively. Statistical analysis using an independent t-test revealed that no significant differences were found in the mean RTV difference of the groups (P > 0.05). CONCLUSION: Within the limitations of this in vitro study, the titanium socket for the zirconia abutment did not show a significant effect on screw loosening under thermal stress compared to the titanium abutment in the internal connection implant.

Fracture resistance of zirconia and resin nano ceramic implant abutments according to thickness after thermocycling / 대한치과보철학회지

PURPOSE: The aim of this in vitro study is to investigate load bearing capacity of esthetic abutments according to the type of material and wall thickness. MATERIALS AND METHODS: 70 specimens equally divided into seven groups according to their abutment wall thicknesses. The abutments prepared with titanium 0.5 mm wall thickness were used as a control group (Ti-0.5), whereas zirconia abutments and resin nano ceramic abutments with wall thickness 0.5 mm, 0.8 mm and 1.0 mm were prepared as test groups (Zir-0.5, Zir-0.8, Zir-1.0 and RNC-0.5, RNC-0.8, RNC-1.0). All specimens were tested in a universal testing machine to evaluate their resistance to fracture and all of them underwent thermo-cycling before loading test. Mean fracture values of the groups were measured and statistical analyses were made using two-way ANOVA. RESULTS: Zir-1.0 showed the highest mean strength (2,476.3 ± 342.0 N) and Zir-0.8 (1,518 ± 347.9 N), Ti-0.5 (1,041.8 ± 237.2 N), Zir-0.5 (631.4 ± 149.0 N) were followed. The strengths of RNC groups were significantly lower compared to other two materials (RNC-1.0 427.5 ± 72.1, RNC-0.8 297.9 ± 41.2) and the strengths of all the test groups decreased as the thickness decreases (P < .01). RNC-0.5 (127.4 ± 35.3 N) abutments were weaker than all other groups (P < .05). CONCLUSION: All tested zirconia abutments have the potential to withstand the physiologic occlusal forces in anterior and posterior regions. In resin nano ceramic abutments, wall thickness more than 0.8 mm showed the possibility of withstanding the occlusal forces in anterior region.

Effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement

PURPOSE: To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS: The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at 80℃ after hydrogen peroxide etching. After storage of the specimens in distilled water at 37℃ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (α=0.05). RESULTS: Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P.05). CONCLUSION: Fiber post silanization and subsequent heat treatment (80℃) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study.

Frequency of bone graft in implant surgery / 대한악안면성형재건외과학회지

BACKGROUND: Implant surgery has become popular with the advance of surgical techniques such as sinus lifting, guided bone regeneration, and block bone graft. However, there were no data about the frequency of bone graft during implant surgery. The purpose of this study was to report the frequency and types of bone graft depending on dental implant patients' profile to complement the database regarding implant surgery. METHODS: The implant operations had been performed from January 2006 to October 2014. The upper and lower jaws were divided into six sextants. A total of 792 sextants were included in this study. Patient information including sex, age, sites, bone graft, and types of bone were investigated. RESULTS: A total of 1512 implants had been placed. Male and female sextants were 421 and 371, respectively (M:F = 1:0.88). Average age was 54.3 (ranging from 20 to 88 years old). Implants were placed in the posterior maxilla (322 sextants, 40.7 %), posterior mandible (286 sextants, 36.1 %), anterior maxilla (127 sextants, 16.1 %), and anterior mandible (57 sextants, 7.2 %). Bone graft was performed in 50.3 % of the sextants. Among the bone grafted sites, sinus lifting with lateral approach (22.1 %) and guided bone regeneration (22.7 %) were performed most frequently. CONCLUSIONS: Bone graft in implant surgery was necessary to augment defects. More than half of the sextants needed bone graft for implant installation.

Perceived color shift of ceramics according to the change of illuminating light with spectroradiometer

PURPOSE: Perceived color of ceramics changes by the spectral power distribution of ambient light. This study aimed to quantify the amount of shifts in color and color coordinates of clinically simulated seven all-ceramics due to the switch of three ambient light sources using a human vision simulating spectroradiometer. MATERIALS AND METHODS: CIE color coordinates, such as L*, a* and b*,of ceramic specimens were measured under three light sources, which simulate the CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp). Shifts in color and color coordinate by the switch of lights were determined. Influence of the switched light (D65 to A, or D65 to F9), shade of veneer ceramics (A2 or A3), and brand of ceramics on the shifts was analyzed by a three-way ANOVA. RESULTS: Shifts in color and color coordinates were influenced by three factors (P 5.5). When switched to A, CIE a* increased (Deltaa*: 5.6 to 7.6), however, CIE b* increased (Deltab*: 4.9 to 7.8) when switched to F9. CONCLUSION: Clinically simulated ceramics demonstrated clinically unacceptable color shifts according to the switches in ambient lights based on spectroradiometric readings. Therefore, shade matching and compatibility evaluation should be performed considering ambient lighting conditions and should be done under most relevant lighting condition.

Effect of silane activation on shear bond strength of fiber-reinforced composite post to resin cement

PURPOSE: Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiber-reinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS: Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at 38degrees C). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at 37degrees C. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukey's HSD (alpha=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS: Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiber-reinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION: The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

Three-dimensional finite element analysis of the deformation of the human mandible: a preliminary study from the perspective of orthodontic mini-implant stability / 대한치과교정학회지

OBJECTIVE: The aims of this study were to investigate mandibular deformation under clenching and to estimate its effect on the stability of orthodontic mini-implants (OMI). METHODS: Three finite element models were constructed using computed tomography (CT) images of 3 adults with different mandibular plane angles (A, low; B, average; and C, high). An OMI was placed between #45 and #46 in each model. Mandibular deformation under premolar and molar clenching was simulated. Comparisons were made between peri-orthodontic mini-implant compressive strain (POMI-CSTN) under clenching and orthodontic traction forces (150 g and 200 g). RESULTS: Three models with different mandibular plane angles demonstrated different functional deformation characteristics. The compressive strains around the OMI were distributed mesiodistally rather than occlusogingivally. In model A, the maximum POMI-CSTN under clenching was observed at the mesial aspect of #46 (1,401.75 microstrain [microE]), and similar maximum POMI-CSTN was observed under a traction force of 150 g (1,415 microE). CONCLUSIONS: The maximum POMI-CSTN developed by clenching failed to exceed the normally allowed compressive cortical bone strains; however, additional orthodontic traction force to the OMI may increase POMI-CSTN to compromise OMI stability.

Full mouth rehabilitation on a bilateral condylar fractured patient using orthognathic surgery and dental implant

BACKGROUND: Mandibular displacement is a common complication of condylar fracture. In the mandibular displacement due to condylar fracture, it is difficult to restore both esthetics and function without using orthognathic surgery. CASE DESCRIPTION: This clinical report described a full mouth rehabilitation in the patient with bilateral condylar fractures and displaced mandible using bilateral sagittal split ramus osteotomy (BSSRO) and simultaneous dental implant surgery. Mandibular position was determined by model surgery through the diagnostic wax up and restoration of fractured teeth. The precise amount of the mandibular shift can be obtained from the ideal intercuspation of remaining teeth. CLINICAL IMPLICATION: Mandibular displacement by both condylar fractures can be successfully treated by orthognathic surgery. Determination of occlusal plane and visualization from diagnostic wax up are mandatory for mandibular repositioning of model surgery. Stable occlusion and regular recall check up are needed for long-term outcome.

Curing efficiency of various resin-based materials polymerized through different ceramic thicknesses and curing time

PURPOSE: The aim of this in vitro study was to examine the curing efficiency of various resin-based materials polymerized through ceramic restorations with 3 different thicknesses. Curing efficiency was evaluated by determining the surface microhardness (VHN) of the resin specimens. MATERIALS AND METHODS: Four kinds of resin materials were used. Z350 (3M ESPE Filtek(TM) Z350: A2 Shade), Z250 (3M ESPE Filtek(TM) Z250: A2 Shade) and Variolink(R) II (VL: Ivoclar vivadent, base: transparent) either with or without a self-curing catalyst (VLC: Ivoclar vivadent, catalyst: low viscosity/transparent) were filled into the silicone mold (10 mm diameter, 1 mm thick). They were cured through ceramic discs (IPS e.max Press MO-0 ingot ivoclar vivadent, 10 mm diameter, 0.5, 1 and 2 mm thicknesses) by LED light-curing units for 20 and 40 seconds. Vicker's microhardness numbers (VHNs) were measured on the bottom surfaces by a microhardness tester. Data were analyzed using a 3- way analysis of variance (ANOVA) at a significance level of 0.05. RESULTS: The thickness of ceramic disc increased, the VHNs of all four resin types were decreased (P<.05). The mean VHN values of the resins light cured for 40 seconds were significantly higher than that of LED for 20 seconds in all four resin materials (P<.05). VLC showed significantly higher VHN values than VL regardless of other conditions (P<.05). Z350 and Z250 showed higher values than VL or VLC (P<.01). CONCLUSION: Thinner ceramic disc with increased curing time resulted higher VHN values of all resin materials. The use of a catalyst produced a greater hardness with all polymerization methods. Restorative resin materials (Z350, Z250) showed higher VHN values than resin cement materials (VL, VLC).

Limited or Le fort I down fracture access for widespread osteomyelitis of maxilla

PURPOSE: To compare the case of widespread maxillary osteomyelitis treated through different approach. METHOD: We report the two case of osteomyelitis. In a case, we had gradually removed the small amount of sequestrum for several times. In the other case, intended Le Fort I fracture was done to approach the lesion. RESULT: In the gradual sequestrectomy case, bone formations were found after 4 months. In the other case, after intended Le Fort I down fracture, sequestrectomy of Lt. maxilla was done with the labiobuccal alveolar bone preserved for the prosthodontic treatment.