Ultra short dental implants to support a 3-unit bridge in the lower jaw

Rationale: Dental implant placement requires a minimal amount of available alveolar bone volume, both in terms of bone width as in height. If this is lacking, traditionally regular sized implants are placed after vertical augmentation of the jaw. Such treatment is relatively invasive with subsequent morbidity. More recently, a switch has been made to the use of short implant, circumventing the need for augmentation. The implants which become available to the market become increasingly shorter.

Objective: The aim of this study to evaluate the clinical performance and implant survival statistics of short implants (4 mm in length) in combination with a longer implant in the severy resorbed posterior mandible of partially edentulous patients that will be restored with a 3-unit fixed dental prosthesis (FDP).

Study design: Study population: A prospective case series. The study population will consist of 15 healthy human volunteers with an indication for fixed implant treatment in the severely resorbed lateral parts of the mandible and a relative contraindication for bone augmentation. Subjects are 18 years and older and wear a full arch denture in the opposing jaw.

Intervention (if applicable): At each side of the partially edentulous mandible, two implants will be placed: one implant with a length of 4 mm in the posterior region of the mandible in combination with a longer implant in the premolar region (Straumann Standard Implant, RN, Institut Straumann AG, Basel, Switzerland). After a period of submerged healing for three months the implants are uncovered and a screw-retained 3-unit FDP will be placed on both sides of the mandibula.

Main study parameters/endpoints: Mean marginal bone loss, clinical performance, implant survival.

Secondary study parameters/endpoints: Patient satisfaction (OHIP-NL 49, VAS-Score).

When combined with a longer implant, an ultra-short implant van succesfully used to support a 3-unit Fixed Dental Prosthesis

• 1st appointment (screening, presenting information about the study + informed consent form)

• Informed consent. Data collection (clinical parameters (x-ray, digital images, questionnaires)

• T0Surgical procedure: placing 1 implant in mandible, including normal follow up

• 2 weeks: suture removal, x-ray; 3 months submerged healing)

• T3: Three months after implant placement: Second stage surgery (uncover implants, placement of healing abutment)

• Start of making a suprastructure

• T4: Crown placement (Data collection / xray)

• T16: Sixteen months after implant placement/ 12 months after crown placement (Data collection / xray)

In all subjects four implant (Straumann Standard dental implant, Institut Straumann AG, Basel, Switzerland) are placed by means of a conventional installation procedure in local anesthesia. The use of this 4mm implant in this indication (in combination with a longer implant) is within the indications recommended by the producer en therefore not experimental (figure 2 and 3).