two interforaminal implants in an immediate or delayed loading protocol for the elderly

Conditions: Edentulous Jaw

Summary: the study population comprises 20 completely edentulous patients aged 60 years and older with severe mandible resorption. each patient receives two inter-foraminal implants (neoss ltd., harrogate, uk). following randomization, implants are loaded either immediately after dental implant surgery or three months after implant placement with the locator®-abutment system. at follow-up visits 3, 6 12, 24 and 36 months after loading, implant stability is evaluated with periotest® and ostell®.

hypothesis: especially for gerontoprosthetics, the locator® abutment system offers the possibility of a minimally invasive retention of prosthetic total restorations of edentulous mandibles. the reduced number of 2 interforaminal implants is intended to ensure implantological anchoring with minimal surgical, technical, financial and time expenditure. research question: how safe is this minimally invasive and cost-effective implant and anchoring system in terms of long-term outcome? are the two implant-prosthetic procedures (immediate versus late restoration) different in terms of implant survival time? materials and methods enrollment: * 20 patients without relevant pre-existing conditions, from the age of 60 years * edentulous mandible, alveolar ridge atrophy statistical analysis: when planning the study, it is estimated that bone resorption in the peri-implant area of the immediate-care implants is greater than in the late-treated implants. 10 patients per group are required with a t-test (α = 0.05) and a power of 80% if the null hypothesis is formulated as follows: -difference of means is 0 and the alternative - expected difference of means is 1mm, common standard deviation is 0.75. collective a (open healing - immediate loading): insertion of a new, prefabricated total mandibular prosthesis on the day of the operation immediately postoperatively after screwing in the locator® abutments. polymerization of the corresponding locator® matrices in the newly incorporated lower jaw denture in the patient's mouth. collective b (closed implant healing - conventional loading): 3 months after implantation exposure of the primary closed implants. immediately following insertion of the prefabricated full-thickness uk prosthesis and retention by the implants using locator® abutments. test parameters: 1. intraoperative torque measurement in ncm 2. radiological measurement of periimplant bone height using orthopantomogram 3. 4-point measurement of peri-implant probing depth using who periodontal probe. the measurement is mesial, distal, buccal and lingual of the implant. 4. measurement of bleeding on probing (parameters of peri-implant inflammation) using the who periodontal probe. 5. analysis of implant stability using the periotest® and osstell® measuring instruments according to a standardized scheme: the strength values are performed in a measuring range consisting of a straight line through the center of the implant and the resulting 180 ° circle sector anterior to this line results. after multiple measurements (5-fold) the lowest numerical value for the periotest® and for the rfa (osstell®) the lowest value documented.

Eligibility criteria:
inclusion criteria: * 60 or older * edentulous lower jaw with advanced atrophy * poor fit and retention even with a new prosthesis exclusion criteria: * poor general condition (asa classification grade iv or more), or * high risk situations for implant therapy (e.g. disorders of bone metabolism due to antiresorptive therapy)

Keywords: dentistry mandibular atrophy mandibular overdenture