Dental Implants with Different Neck Design: A Prospective Clinical Comparative Study with 2-Year Follow-Up

Abstract

The present study was conducted to investigate whether a different implant neck design could affect survival rate and peri-implant tissue health in a cohort of disease-free partially edentulous patients in the molar–premolar region. The investigation was conducted on 122 dental implants inserted in 97 patients divided into two groups: Group A (rough wide-neck implants) vs. Group B (rough reduced-neck implants). All patients were monitored through clinical and radiological checkups. Survival rate, probing depth, and marginal bone loss were assessed at 12- and 24-month follow-ups. Patients assigned to Group A received 59 implants, while patients assigned to Group B 63. Dental implants were placed by following a delayed loading protocol, and cemented metal–ceramic crowns were delivered to the patients. The survival rates for both Group A and B were acceptable and similar at the two-year follow-up (96.61% vs. 95.82%). Probing depth and marginal bone loss tended to increase over time (follow-up: t1 = 12 vs. t2 = 24 months) in both groups of patients. Probing depth (p = 0.015) and bone loss (p = 0.001) were significantly lower in Group A (3.01 vs. 3.23 mm and 0.92 vs. 1.06 mm; Group A vs. Group B). Within the limitations of the present study, patients with rough wide-neck implants showed less marginal bone loss and minor probing depth, as compared to rough reduced-neck implants placed in the molar–premolar region. These results might be further replicated through longer-term trials, as well as comparisons between more collar configurations (e.g., straight vs. reduced vs. wide collars).

Assessment of Peri-Implant Soft Tissues Conditions around Short and Ultra-Short Implant-Supported Single Crowns: A 3-Year Retrospective Study on Periodontally Healthy Patients and Patients with a History of Periodontal Disease

“…Moreover, the convergent crest module in short and ultra-short implants seems to have an important influence on marginal bone loss. Referring to biomechanical models which compare different crest modules, the quantity of bone present around the neck of the implant is fundamental for the distribution of the occlusal forces [ 62 , 63 ]. The transmission of vertical, horizontal and rotational forces on F-BIC is thus more favorable and homogeneous in implants with convergent crest module compared to implants with divergent crest module with the same diameter.…”

Peri-Implant Behavior of Tissue Level Dental Implants with a Convergent Neck

“…The Rhinoceros ® application (Robert McNeel & Associates, Seattle, USA) was used to measure bone loss, allowing us to scale the images and measure mesial and distal radiographic bone loss. Other authors have adopted the same method [ 8 , 13 , 21 , 22 ].…”

“…Traditionally, a bone loss of <1.5 mm around the implant during the first year has been considered to be physiological. However, this figure needs to be redefined, since recent studies have found that bone loss is approximately between 0.8 ± 0.4 mm [ 6 , 7 ], and is dependent upon a range of factors such as the morphology and geometry of the implant, the surface of the implant neck, the technique used to place the implant, the patient habits, and the type of prosthesis [ 5 , 7 , 8 , 9 , 10 ].…”

“…The implant can be placed at either a crestal level (bone level), with two interfaces (one between the implant and the transepithelial abutment, and another between the latter and the prosthesis, generating two microgaps) or at a supracrestal level (tissue level), with a single interface that acts as the junction between the implant and the prosthesis, and separates the microgap from the bone area reducing bacterial filtration in that zone [ 7 , 8 , 11 , 12 , 13 ]. Within supracrestal implants we find implants with a convergent transmucosal neck that present greater stability of the peri-implant tissues by leaving more space for the collagen fibers of the ligament to guarantee coronal migration and which were introduced following the Biological Oriented Preparation Technique (BOPT) philosophy proposed by Dr. Loi [ 14 , 15 ].…”

Special Issue: Dental Implant Materials 2019

“…A review of this Special Issue summarizes the relevant literature to establish guidelines regarding the effects of connection type between abutments and implants in soft and hard tissues [ 6 ]. Biomechanical behaviours of implant-abutment connection designs are shown in two articles, and clinical outcomes are presented in one article, depending on the connection designs [ 7 , 8 , 9 ]. It is necessary for researchers and clinicians to interpret the clinical data in implantology in the light of the old axioms that pocket formation is the initiator for peri-implant or periodontal inflammation and that bone responds to strain, not to stress itself.…”