Retrieval of the resilient element in an osseointegrated implant system

A Technique to Salvage a Single Implant-Supported Fixed Dental Prosthesis Having a Nonretrievable Implant Screw Fragment

An implant screw fracture is one of the common problems associated with the implant components. In some situations, it may not be possible to retrieve the fractured implant screws. As a result, clinicians either remove the implant or the implant may need to be covered over with soft tissue. The salvage of an implant with a nonretrievable screw fragment may be highly beneficial to the patients. This report describes a technique to salvage an implant-supported single restoration that has a nonretrievable implant screw fragment.

Mode superposition transient dynamic analysis for dental implants with stress-absorbing elements: a finite element analysis

The purpose of this study was to analyze the dynamic behavior of a dental implant with a stress-absorbing element, using dynamic analysis. Two model types, stress-absorbing model with a resilient stress absorber made of polyoxymethylene and non-stress-absorbing model with rigid titanium, were employed. In both model types, the implant was 4.0 mm in diameter and 13.0 mm in length and placed in the mandibular first molar region. Shapes of the finite element implant and implant-bone were modeled using computer-aided design. All calculations for the dynamic analysis were performed using the finite element method. It was found that the stress-absorbing model had a lower natural frequency than the non-stress-absorbing model. In addition, the stress-absorbing model had a higher damping effect than the non-stress-absorbing model. It was concluded that mode superposition transient dynamic analysis is a useful technique for determining dynamic behavior around dental implants.

Reconstructive materials and bone tissue engineering in implant dentistry

Periodontal function for natural teeth and dental implants depends strongly on the mechanical integrity of the bone in the maxilla and mandible. Ongoing healthy bone remodeling around a natural tooth or implant is critical for longevity. Chemical factors that influence bone remodeling have been explored with the goal of enhancing the growth and maintenance of good quality bone. Less, but increasing, effort has been directed at understanding mechanical signals and factors, including those affected by implant/prosthesis materials that transmit loads directly to the surrounding bone. This article reviews research on the effects of synthetic materials and resulting mechanical stimuli on bone tissue engineering in dentistry.

Clinical experiences with a new maintenance-free shock absorbing element in titanium implants

Until now, the biokinetic elements of one implant system were to be substituted once a year in order to prevent complications of fractures of fixation screws. In this article a new implant with a maintenance-free shock absorbing element was examined. During the last 6 years, 384 dental implants with a biokinetic element (mobile-implant, SIS Inc., Klagenfurt, Austria) were placed in 138 patients. The implants were loaded with prosthetic superstructures 4 months after implantation. For comparison, 160 patients were treated with 494 conventional titanium implants of the same design without biokinetic elements. All patients were examined radiologically and clinically. Periimplant probing depth, periimplant bleeding, Periotest-values (Siemens, Bensheim, Germany) at the time of prosthetic treatment and 3, 6, 9, 12, and 24 months after implant loading were registered. Implantation was successful in 97.2% of mobile-implants and 98% of conventional implants. There was a low degree of sulcus bleeding and high degree of physiological periimplant probing depths in both patients groups. In mobile-implants, the Periotest-values were positive and similar to that of the control. There was no difference between the values in the maxilla and mandible. In the group with conventional implants, the Periotest-values were negative and showed a low degree of negativity during the first 12 months after implant loading. Periotest-values in the upper jaw were higher than in the lower jaw. There was a lower degree of periimplant bone loss after implant loading in patients with mobile-implants. In conclusion, mobile-implants demonstrate the positive effects of implants with shock absorbing elements. They are maintenance free.

Biomechanical properties in titanium implants with integrated maintenance free shock absorbing elements

Good functional properties are essential in dental implantology. Bio-kinetic elements are imitating dental resilience. In this study a new kind of implants with maintenance free shock absorbing elements will be introduced and their bio-mechanic properties reported. The mobile implant (SIS Inc., Klagenfurt, Austria) is a self-cutting conical screw implant with an integrated bio-kinetic element. The shock absorber is a central part of the implant and a titanium ring closes the shock absorbing unit within the implant. The resilience of the implant was tested by axial and horizontal loading in a special testing unit. Furthermore, a survival test of the elastic titanium ring in the most exposed cervical part of the implant was performed. The region was examined by electron microscopy after 12 million movements in the axial and horizontal direction. A progressive shock absorption was registered during horizontal and axial movements. The maximum movements were 0.06 mm in the axial and 0.16 mm in the horizontal direction. There were seen no signs of material destruction in the electron microscopic analysis. A maintenance-free bio-kinetic implant with progressive shock absorbing qualities was registered.

A natural tooth's stress distribution in occlusion with a dental implant

The loss of one or more teeth is normally treated with conventional fixed or removable partial dentures or with implant supported fixed or removable dentures. This study investigated stresses formed around the implant and the antagonist natural tooth under occlusal force in the substitution of a missing lower first molar with a rigid or resilient IMZ (Intra Mobil Zylinder) implant, using the finite element stress analysis method. The results indicate that a bite force of 143 N resulted in high compressive stresses around the roots of a natural tooth opposing a restoration supported by an IMZ implant with rigid type abutment. It is speculated that these high compressive stresses may contribute to intrusion of the tooth.

Professional hygiene care, adjustments and complications of mandibular implant-retained overdentures: a three-year retrospective study

PURPOSE

This report presents a retrospective evaluation of postinsertion care required by 104 edentulous patients with advanced mandibular bone loss.

MATERIAL AND METHODS

The patients were treated with new maxillary dentures and mandibular overdentures retained by two implants with a single bar-clip attachment. Distinction was made between professional hygiene care, adjustments, and treatment of complications. The follow-up period after insertion of dentures was 3 years for all patients.

RESULTS

Approximately a third of the patients needed professional hygiene care. The need for adjustments declined during the years of function. Complications were encountered in approximately a third of the patients. The majority of these were not related to the implants, but to the superstructure and both the maxillary and mandibular dentures.

CONCLUSIONS

Many edentulous patients with advanced mandibular bone loss who were treated with mandibular implant-retained overdentures need professional hygiene care, adjustments, and treatment of complications.