Clinical trial NCT03558347: CF41102 5-year Clinical Evaluation of Conelog® Implant With 7 mm Length
Official title: 5 Year Clinical Evaluation of CONELOG® Screw-Line Implants With 7 mm Length: a Prospective Randomized Double-blinded Clinical Study
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Dental Implants
Partial Edentulism
Lead sponsor: RWTH Aachen University
Sponsor class: OTHER
Collaborators: name: Camlog Oral Reconstruction Foundation
First posted: 2018-06-15
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: This study consists of 20 patients (15 female, 5 male, mean age 59) who, after implant placement and second stage surgery, are randomly divided into two groups: group A was treated with two splinted crowns, group B with non-splinted single crowns. Four patients with bilateral free-end situation received both splinted and non-splinted restorations.
Primary purpose: TREATMENT

Brief summary: The objective of this prospective, randomized, pilot study is to determine whether the Conelog® connection is suitable for splinted/non-splinted cemented crowns in the chewing centre (focus only on implant-abutment connection) and whether implants with the Conelog® connection and a length of 7mm are suitable for use in the molar region of the lower jaw.

Detailed description: In order to avoid sinus augmentation in the upper jaw and a vertical augmentation in the lower jaw, various manufacturers offer short implants of 6-8mm length. The prevention of augmentative measures, especially in the mandible, is a fundamental component of the minimization of invasiveness while at the same time improving the functional capability. The benefit lies in the possibility to place implants without prior bone augmentation even in difficult anatomical conditions. This significantly reduces the invasiveness which on the one hand allows a higher number of patients to be treated with implants (especially morbid patients and anxiety patients) and on the other hand makes the treatment more predictable, with less risk, cost-efficient and considerably faster. Moreover, new scientific insights are gained in the area of short implants.

As with all implants, the risks associated with the study consist of intraoperative complications (e.g. damage of adjacent structures), failure of the implant (e.g. impairment of wound healing, fracture of the implant body), the abutment or abutment screw (e.g. loosening, fracture), or the crown on the abutment (veneer fracture, scaffold fracture).

The objective is to determine whether implants with the Conelog® connection and a length of 7mm are suitable for splinted/non-splinted monolithic lithium disilicate crowns cemented on individualized titanium abutments in the chewing centre of the mandible. The main indication for short implants is severe atrophy of the jaw, which creates a longer distance from the implant shoulder to the occlusal plane. An unfavourable crown-to-implant ratio means higher stress on the screws, the implant-abutment surface and possibly on the osseointegration of the implants. This raises the question whether splinted crowns have a positive effect on implant survival compared to non-splinted crowns.

The two 7mm Conelog ® implants are either used in the area of the second premolar and the first molar or the first and second molars of the mandible. The diameter of the implant depends on the width of the alveolar bone and ranges from 3.8 to 4.3 mm.

In case of a bilateral free-end situation, both quadrants are treated as part of the study, and both treatment variants are applied by using splinted crowns on one side and individual crowns on the other (split mouth design).

20 patients will be included in the study, which will be divided into two equally sized groups of 10 patients. All patients are recruited by the three clinical investigators at the Department of Prosthodontics and Biomaterials, Centre for Implantology, Medical Faculty, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH) Aachen University Hospital. In order to achieve sufficient patient numbers, the population of Aachen will be informed via print media.

Each patient receives a single dose of antibiotics one hour prior to implant surgery. A mucoperiosteal flap was mobilized and the implants were placed as recommended by the manufacturer, using a surgical template as a guide. Healing abutments were screwed, and submerged healing is used for all implants. Second stage surgery is performed after 3 months. The prosthetic restoration is completed within 4 weeks after exposure.

Patients in group A will receive splinted monolithic lithium disilicate crowns cemented on individualized titanium abutments. Patients in group B will receive 2 non-splinted monolithic lithium disilicate-crowns cemented on individualized titanium abutments.

The cementation is done with Multilink Implant ® on the machined abutments, which have been cleaned for 5 minutes in an ultrasonic cleaner with 95% alcohol. The crowns are conditioned with hydrofluoric acid for 20 seconds and silanized with Monobond Plus® for 60 seconds. The day of insertion of the restoration is marked as baseline.

The examination performed at baseline and the follow up after 6 months includes occlusion, probing depth, plaque index and the condition of the ceramic surface of the crowns. Additionally, radiographs with customized positioning jigs are taken at baseline, after 1, 3, and 5 years.

Eligibility criteria: Inclusion Criteria:

* female and male subjects older than 18 years
* absence of all molars and, optionally, the second premolar in at least on quadrant of the lower jaw
* the periodontal situation of the other teeth is healthy or periodontal treatment has already been successfully performed
* the antagonists are natural teeth or treated with fixed dentures
* good health according to the ASA Physical Status Classification System one or two (ASA 2010)
* good oral hygiene and an at most moderate tobacco consumption
* bone height above the N. alveolaris inferior of at least 11mm and the precondition of a one-stage implantation and augmentation
* signed consent

Exclusion Criteria:

* Indication for large augmentations of the jaw bone
* Bone abundance with minimal risk of injury to neighbouring structures when using two 11 mm or longer implants
* Psychological disorder
* substance abuse
* removable dentures (with or without implants)
* pregnancy
* patients under age or unable to reason
* persons who are placed in an institution on a judicial or administrative order

Primary outcomes:
measure: marginal bone loss
timeFrame: 5 years
Secondary outcomes:
measure: probing depth
timeFrame: 5 years
measure: gingival status
timeFrame: 5 years
measure: oral hygiene
timeFrame: 5 years
measure: survival rate of prosthetic restoration
timeFrame: 5 years
Other outcomes:
Locations:
city: Aachen
country: Germany
facility: Universitätsklinikum Aachen
state: NRW
Study officials:
affiliation: University Hospital, Aachen
name: Stefan Wolfart, Prof. Dr.
role: STUDY_DIRECTOR
References:
citation: Tawil G, Aboujaoude N, Younan R. Influence of prosthetic parameters on the survival and complication rates of short implants. Int J Oral Maxillofac Implants. 2006 Mar-Apr;21(2):275-82.
citation: Misch CE. Short dental implants: a literature review and rationale for use. Dent Today. 2005 Aug;24(8):64-6, 68.
citation: Vehemente VA, Chuang SK, Daher S, Muftu A, Dodson TB. Risk factors affecting dental implant survival. J Oral Implantol. 2002;28(2):74-81. doi: 10.1563/1548-1336(2002)0282.3.CO;2.
citation: Gentile MA, Chuang SK, Dodson TB. Survival estimates and risk factors for failure with 6 x 5.7-mm implants. Int J Oral Maxillofac Implants. 2005 Nov-Dec;20(6):930-7.
citation: Urdaneta RA, Rodriguez S, McNeil DC, Weed M, Chuang SK. The effect of increased crown-to-implant ratio on single-tooth locking-taper implants. Int J Oral Maxillofac Implants. 2010 Jul-Aug;25(4):729-43.
citation: Li R, Sun W, Shi B. [Retrospective analysis of placing short dental implants in the posterior areas]. Zhonghua Kou Qiang Yi Xue Za Zhi. 2010 Dec;45(12):708-11. Chinese.
citation: Yi YS, Emanuel KM, Chuang SK. Short (5.0 x 5.0 mm) implant placements and restoration with integrated abutment crowns. Implant Dent. 2011 Apr;20(2):125-30. doi: 10.1097/ID.0b013e31820fb67e.
citation: Etoz OA, Ulu M, Kesim B. Treatment of patient with Papillon-Lefevre syndrome with short dental implants: a case report. Implant Dent. 2010 Oct;19(5):394-9. doi: 10.1097/ID.0b013e3181ed0798.
citation: Ogawa T, Dhaliwal S, Naert I, Mine A, Kronstrom M, Sasaki K, Duyck J. Effect of tilted and short distal implants on axial forces and bending moments in implants supporting fixed dental prostheses: an in vitro study. Int J Prosthodont. 2010 Nov-Dec;23(6):566-73.
citation: Wu H, Li JH, DI P, Qiu LX, Lin Y, Luo J. [A long-term retrospective clinical study of short dental implant restoration]. Zhonghua Kou Qiang Yi Xue Za Zhi. 2010 Dec;45(12):712-6. Chinese.
citation: De Santis D, Cucchi A, Longhi C, Vincenzo B. Short threaded implants with an oxidized surface to restore posterior teeth: 1- to 3-year results of a prospective study. Int J Oral Maxillofac Implants. 2011 Mar-Apr;26(2):393-403.
citation: Neldam CA, Pinholt EM. State of the art of short dental implants: a systematic review of the literature. Clin Implant Dent Relat Res. 2012 Aug;14(4):622-32. doi: 10.1111/j.1708-8208.2010.00303.x. Epub 2010 Oct 26.
citation: Raviv E, Turcotte A, Harel-Raviv M. Short dental implants in reduced alveolar bone height. Quintessence Int. 2010 Jul-Aug;41(7):575-9.
citation: Hasan I, Heinemann F, Aitlahrach M, Bourauel C. Biomechanical finite element analysis of small diameter and short dental implant. Biomed Tech (Berl). 2010 Dec;55(6):341-50. doi: 10.1515/BMT.2010.049. Epub 2010 Oct 28.
citation: Al-Sawaf O, Tuna T, Rittich A, Kern T, Wolfart S. Randomized clinical trial evaluating the effect of splinting crowns on short implants in the mandible 3 years after loading. Clin Oral Implants Res. 2020 Nov;31(11):1061-1071. doi: 10.1111/clr.13652. Epub 2020 Sep 12.