The aging society of the global population has led to an increase in the number of patients with edentulous jaw, a common multiple disease. Given the developments in implant techniques, the method of implant denture has received a positive and good response in terms of the quality of life and psychological well-being of patients. Implant-supported overdenture in mandible has two main advantages. 1) It has better retention and chewing efficiency than those of mandibular conventional denture. The required implant site of implant-supported overdenture is less than that of fixed implant-supported denture and can repair more defect tissues to help restore beauty and pronunciation. The price of the former is more acceptable than that of the latter. Therefore, this article aimed to systemically analyze and further discuss the clinical effect of implant-supported overdenture in elderly patients; combine existing related studies on the selection of number, site, and upper restoration of implants; and illustrate the advantages of removable implant-supported protheses in the repair of toothless mandible.
Aged ; Dental Implants ; Dental Prosthesis, Implant-Supported ; Denture Retention ; Denture, Overlay ; Humans ; Jaw, Edentulous ; Mandible ; Patient Satisfaction ; Quality of Life ; Treatment Outcome

This case study was to report the possible increase in the denture retention and psychological relief using the implant-supported fixed prostheses in a completely edentulous patient. The implants were placed in the anterior portion of the mandible in a patient who had completely edentulous state following the extraction of residual abutment teeth, and consequently a distal extension removable partial denture was fabricated. The patient's adaptation and satisfaction to the new prosthesis was monitored and confirmed in terms of masticatory function and esthetics, by restoring the oral condition similar to initial status before the residual teeth extraction. After 6 months, radiographic examination confirmed that both the abutment teeth and the implants were stable and well maintained. Considering the relatively short clinical follow-up period, however, continuous long-term monitoring was required.
Dental Prosthesis, Implant-Supported ; Denture Retention ; Denture, Partial, Removable ; Esthetics ; Follow-Up Studies ; Humans ; Mandible ; Mandibular Prosthesis ; Prostheses and Implants ; Tooth

PURPOSE: The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS: Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at 106 cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). RESULTS: The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). CONCLUSION: The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.
Crowns ; Dental Implants, Single-Tooth ; Dental Prosthesis Retention ; Dental Prosthesis, Implant-Supported ; Diamond ; Prosthesis Failure ; Titanium ; Torque*

OBJECTIVETo evaluate the effect of different auxiliary resistance forms on the resistance and marginal fitness of complete crowns for short molar preparations.

METHODSA total of 70 Nissin resin teeth were prepared with 20° total occlusal convergence, 2.5 mm of occlusocervical height, and a shallow finish line on a milling machine. The milled preparations were then randomly assigned to 7 groups of 10. The first group was used as the control group. A total of 30 dies were modified by preparing interproximal grooves with angles of 0°, 6°, and 20° centered on the mesial and distal surfaces of the dies. The rest of the teeth were prepared with occlusal holes in the center of the occlusal surface milled with the same burs to form 0°, 6°, and 20° holes. Cobalt-chromium copings were fabricated for all specimens. The marginal gap of specific points on the axial surface was measured before and after cementation. The resistance of each specimen was evaluated by applying an external force at an angle of 45° to the long axis of the die by using a universal testing machine in a lingual to buccal direction. The maximum force applied before crown dislodgement was measured. Data were analyzed using the SAS 9.2 software.

RESULTSThe results showed that the 0° groove, 0° hole, and 6° hole were effective in improving the resistance of the complete crowns (P<0.05). The 0° groove, 6° groove, 0° hole, 6° hole, and 20° hole had significant difference with the control group in terms of marginal discrepancies (P<0.05).

CONCLUSIONAuxiliary resistance forms with less degree indicate greater resistance force but worse marginal fitness. In clinical practice, if the resistance of a preparation is enough, the auxiliary resistance forms should be avoided from being used.

Implant prosthodontics is beneficial for edentulous patients in enhancing the support, retention, stability, phonation and so on. Various types of prosthesis supported by implant, including implant retained- or supported-overdenture for the removable type and ceramo-metal and fixed prostheses with processed acrylic teeth for the fixed type, are frequently used. Treatment planning for the prosthesis with implant must be made after considering individual characteristics such as form of residual ridge, soft tissue, interocclusal relationship, economic status. Fixed prosthesis with processed acrylic teeth (also known as 'implant hybrid prosthesis' or 'bone anchored bridge') has the advantages of both removable and fixed prosthesis such as proper soft tissue profile, esthetic outcome, increased masticatory efficiency and psychological stability. The 73-years-old female patient came to the department of prosthodontics, Dental hospital of Yonsei University. She was diagnosed with Kennedy class I partial edentulism in the maxilla and complete edentulism in the mandible. This article reports a satisfactory clinical and esthetic outcome of full mouth rehabilitation using removable partial denture in the maxilla and implant hybrid prosthesis in the mandible.
Chimera ; Dental Prosthesis, Implant-Supported ; Denture, Partial, Removable ; Female ; Humans ; Mandible ; Maxilla ; Mouth ; Mouth Rehabilitation ; Phonation ; Porphyrins ; Prostheses and Implants ; Prosthodontics ; Retention (Psychology) ; Tooth

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar(R) is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar(R) was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar(R) system in a mandibular edentulous patient.
Aged ; Dental Prosthesis, Implant-Supported ; Denture, Complete ; Denture, Overlay ; Denture, Partial, Removable ; Dentures ; Female ; Humans ; Jaw, Edentulous ; Joints ; Mandible ; Maxilla ; Retention (Psychology) ; Tooth ; Welding

The presence of a large palatal or maxillary defect after partial or total maxillectomy for tumor, trauma or congenital deformation poses a challenge to prosthodontists, particularly when the use of an implant cannot be considered. This case report described the use of an air valve in a hollow silicone obturator to manufacture an inflatable obturator that could be extended further into undercut area to retain itself. The inflatable obturator exhibited adequate retention, stability and border sealing, thereby improving the masticatory,pronunciation and swallowing functions of patients. It may be a suitable alternative treatment option to an implant-retained obturator.
Dental Impression Technique ; Dental Prosthesis Design ; Dental Prosthesis Retention ; Denture Retention ; Denture, Complete, Upper ; Fibrous Dysplasia of Bone ; rehabilitation ; surgery ; Humans ; Male ; Maxilla ; surgery ; Orthognathic Surgical Procedures ; instrumentation ; methods ; rehabilitation ; Palatal Obturators ; Silicones ; Treatment Outcome ; Young Adult

Completed denture or immediate completed dentures were manufactured before operation to three patients with edentulous mandible and maxillary or severe chronic periodontitis. The remnant teeth of patients were extracted. Four Ankylos implants were implanted in mandible, and six implants were implanted in maxillary. SynCone conical bases were placed into implants, prefabricated conical crowns were inserted into conical bases, and temporary dentures were completed. After 3-12 months, temporary dentures were replaced by overdenture with casting frame. Except that one implant had been lost and was replaced by a new implant after 1 month of treatment, the rest implants had no obvious frontal resorption in 12-24 months of follow-up.
Crowns ; Dental Implants ; Dental Prosthesis, Implant-Supported ; Dental Restoration Failure ; Denture Design ; Denture Retention ; Denture, Overlay ; Humans ; Jaw, Edentulous ; Mandible ; Maxilla

OBJECTIVETo determine ITI implants stability in different bone types using RFA and to provide evidence for feasibility of early loading.

METHODSA total of 104 ITI sand-blasted large-grit acid-etched (SLA) implants in 50 patients were classified into 3 groups according to bone type. Resonance frequency analysis was conducted at 0, 1, 4, 6, 8 and 12 weeks after installation.

RESULTSThe survival rate was 100%. Primary stability was affected by bone type (P < 0.001). The implant stability quotient (ISQ) was significantly higher in type I bone than in type IV bone. At 12 weeks, there was no significant difference among the 3 groups. Comparison of ISQ was made between 6 th week and 12 th week for all bone types, there was no significant difference for type I and III (P > 0.05) while there was for type IV (P < 0.001).

CONCLUSIONSEarly loading with ITI SLA implants placed in type I, III bone were highly predictable.

OBJECTIVETo analyze the stress distribution on cast retentive clasp arms in dislodging denture, and to discuss the deepest undercuts of the second mandibular premolar (abutment) for cobalt-chromium alloy cast clasps with different widths.

METHODSThree-dimensional finite element models of the abutment with different depths of undercuts and retentive arms with different widths were set up. Dynamic displacement load (3 mm/s) was exerted on the middle of the retentive arms to analyze the stress in retentive arms while they were being removed from the abutment.

RESULTSThe peak stress in retentive arms was positively correlated to the undercuts displaced by clasp tips, and those were not obviously related to the undercuts displaced by the middle of retentive arms. When width/thickness of retentive arms was 3, the increase of peak stress of retentive arms with similar locations of clasp tips was significantly related to the increase of the arm width. The deepest undercuts of the second mandibular premolar for cobalt-chromium alloy cast retentive arms with different widths of 1.8 mm, 1.6 mm, and 1.4 mm were 0.25 mm, 0.30 mm, and 0.35 mm respectively.

CONCLUSIONSWhen width/thickness of the retentive clasp arm is fixed, the wider the arm is, the smaller depth it should be placed on the undercut of abutment. Retentive clasp arms with different widths should be placed on different depths of undercuts in order to prevent their permanent deformation.