Trial document





This trial has been registered retrospectively.
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  DRKS00006555

Trial Description

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Title

Biomolecular and histological evaluation (study part 1) / Longevity of lithium disilicate abutment crowns (study part 2): prospective, randomized pilot study

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Trial Acronym

[---]*

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URL of the Trial

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Brief Summary in Lay Language

When a premolar or molar tooth cannot be saved or already is missing, the dental prosthodontic rehabilitation can be reached by using an implant as root replacement and an artificial crown made of tooth-colored ceramics. The success of the restorations shall be followed over a period of three years.
The implant insertion will take place independently from the study, following the clinic’s common, established and standardized procedure. After an adequate healing period for the still tissue covered implant, the study starts with the surgical implant exposure.
The – as standard – necessary tissue management around the implant, three materials, which are already in clinical use, will be used for the abutments (the intermediate element between the bone integrated implant and the dental restoration itself). Lithium disilicate (glass ceramics), densely sintered zirconia (oxide ceramics) and titanium will be used (study part 1). The sequence of the abutments will be randomly chosen (randomization). The different influence of the materials on the soft tissue surrounding the implant will be biomolecularly (sampling fluid at the implant site) and histologically (kind and number of cells and their differentiation) assessed.
The samples for the biomolecular analysis will be taken with paper tips, which are painlessly positioned into the sulcus around the implant for a short period of time (a few seconds). The samples will be taken once a week for four weeks respectively after inserting each abutment.
Small tissue samples for the histological evaluation will be collected circularly around the implant using a biopsy punch. The punch is a commonly used method for inserting or exposing implants. The biopsy punch will provide tissue samples of 1mm thickness. Overall 4 biopsy samples will be taken. The tissue harvested at implant exposure will serve as histological reference.
Subsequently, after wearing each of the three abutment materials, a punch biopsy will provide samples for the assessment of the interaction between tissue and the three materials.
The number, kind and differentiation of cells will be histologically examined. Rare complications in (punch) biopsy could be wound healing disturbance or infections and thus post-surgical pain.
In study part 2, the implants will be definitely restored with a super structure (abutment crown). The restorations consist of a titanium base onto which a crown is bonded and will be screw-retained in the implant. Once the abutment crown has been inserted, follow-up examinations are scheduled after 1 day, 4 weeks, 1, 2, and 3 years.
Aim of the study is the evaluation of the interaction between the implant surrounding soft tissues and different, clinically established abutment materials. The different influence of the materials on the soft tissue surrounding the implant will be biomolecularly (sampling fluid at the implant site) and histologically (kind and number of cells and their differentiation) assessed. The material is a glass ceramic material for dental restorations which is appropriate for the long term function in the oral cavity.
The implant insertion will not be part of the study. The costs will be covered by the health insurance or the patient him- or herself.
All materials used within the clinical trial are medical devices, which are certified by the European Community according the §§ 8 to 10 of the German medical devices law and will be used according to their intended purpose.
All patients who would like an implant treatment of a tooth space and who are complying with the inclusion criteria - and accordingly cases without applicable exclusion criteria – are eligible for the study.
The hypothesis under examination in the first study part is that the interface “soft tissue – abutment material” will differ histologically and biomolecularly depending on the material used.
In the second study part, the hypothesis, that clinical longevity of monolithic screw-retained lithium disilicate crowns is comparable to that of high strength ceramic crowns as given by literature, will be tested.

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Brief Summary in Scientific Language

Using titanium-base implants offers the possibility to successively insert different materials and for intra-individual assessment. The combined evaluation of biomolecular methods with biopsy material allows for a detailed appraisal of the interaction with the surrounding soft tissues. Noteworthy for the biomolecular marker analysis is that the enzyme activity (PMN elastase, MMP-8 und IL-1β, calprotectin) can be determined even from smallest volumes of peri-implant crevicular fluid (PICF).
This procedure has not been used in previous studies in this field.
The results will have a high impact, as the prevalence of peri-implant mucositis is raising. Peri-implant mucositis is a multi-factorial disease with a partly still unexplored etiology. The influence of a smoking habit on periodontitis has been frequently examined.
The study at hand aims to enlighten the material aspects on a differentiated level. A higher disposition for gingivitis as a reaction of soft tissues to a certain material principally could lead to the conclusion, that the disposition for peri-implantitis would be raised accordingly. Further examination will be necessary here.
A great number of different abutment systems are available on the dental market and there are different philosophies regarding advantages and disadvantages of certain systems. The 3-year follow-up study of the monolithic screw-retained lithium disilicate abutment crowns in the second study part shall deliver data on this specific system. To date, little research on that topic has been published. Standardized clinical protocols for the evaluation of the interaction between peri-implant soft tissues and dental materials on a biomolecular as well as histological level are lacking. Furthermore, studies on the clinical longevity of lithium disilicate abutment crowns are still missing.
Twenty-four patients (including three feasibility test cases) presenting to our clinic for the treatment of a single missing tooth will be eligible for the study, if the implant treatment option is chosen. The implant insertion will take place independently from the study according to the common, established and standardized procedure of the clinic (three-dimensional implant position planning and implant insertion using a planning and surgical template).
After an adequate healing period for the still tissue covered implant, the study starts with the surgical implant exposure. As a standard during implant treatment in the Department of Prosthetic Dentistry, the soft-tissue management with healing abutments will take place before the permanent restoration is fixed to the implant. Three different clinically established abutment materials (lithium disilicate, densely sintered zirconia and titanium) will be luted to titanium bases and shall be used in randomized order for soft-tissue shaping (study part 1). The different influence of the materials on the soft tissue surrounding the implant will be biomolecularly (sampling fluid at the implant site, peri-implant crevicular fluid (PICF)) and histologically assessed.
In the second study part, follow-up examinations of the monolithic screw-retained lithium disilicate crowns shall take place for three years.
The hypothesis under examination in the first study part is that the interface “soft tissue – abutment material” will differ histologically and biomolecularly depending on the material used.
In the second study part, the hypothesis, that clinical longevity of monolithic screw-retained lithium disilicate crowns is comparable to that of high strength ceramic crowns as given by literature, will be tested.
Primary outcome (study part 1):
• Biomolecular analysis of the enzyme activity as parameter for the healing process (PMN-elastase, MMP-8, IL-1β, calprotectin)
Secondary outcomes (study part 1):
• Histological analysis of the punch biopsy samples (kind, number and differentiation of cells, plaque accumulation)
• Clinical parameters: pocket depth (TT), Gingiva Index (GI), Plaque Index (PI), Bleeding on probing (BOP)

Primary outcome (study part 2):
3-year survival of the abutment crowns: yes/no
Secondary outcomes (study part 2):
• Survival until abutment crown loss, continuous
• Biological and technical complications (peri-implantitis (biological), abutment loosening (technical), screw fracture (t), loss of retention (t)) and treatment failure (implant loss (b), abutment crown fracture (t))
• Clinical parameters: pocket depth TT, Gingival Index GI, Plaque Index PI, Bleeding on Probing (BOP) and Pink Esthetic Score (PES)

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Organizational Data

  •   DRKS00006555
  •   2014/10/27
  •   [---]*
  •   yes
  •   Approved
  •   68/13, Ethik-Kommission der Universität Ulm
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Secondary IDs

  • [---]*
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Health Condition or Problem studied

  •   K08.1 -  Loss of teeth due to accident, extraction or local periodontal disease
  •   K00.0 -  Anodontia
  •   K02.9 -  Dental caries, unspecified
  •   K04.9 -  Other and unspecified diseases of pulp and periapical tissues
  •   K05.6 -  Periodontal disease, unspecified
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Interventions/Observational Groups

  •   Suty part 1: Lithium disilicate abutment (glass ceramic)
  •   Study part 1: Densely sintered zirkonia abutment (oxide ceramic)
  •   Study part 1: Titanium alloy abutment
  •   Study part 2: Follow-up of the longevity after inserting monolithic screw-retained lithium disilicate abutment crowns after 1, 2 and 3 years
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Characteristics

  •   Interventional
  •   [---]*
  •   Randomized controlled trial
  •   Blinded
  •   data analyst
  •   Active control (effective treament of control group)
  •   Treatment
  •   Crossover
  •   N/A
  •   N/A
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Primary Outcome

Primary outcome (study part 1):
• Biomolecular analysis of the enzyme activity as parameter for the healing process (PMN-elastase, MMP-8, IL-1β, calprotectin) at baseline and 1, 2, 3, and 4 weeks after inserting the respective abutment

Primary outcome (study part 2):
3-year survival of the abutment crowns: yes/no

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Secondary Outcome

Secondary outcomes (study part 1):
• Histological analysis of the punch biopsy samples (kind, number and differentiation of cells, plaque accumulation) at baseline (implant exposure) and 4.5 weeks after insertion of the respective abutment made of three different materials
• Clinical parameters: pocket depth (TT), Gingiva Index (GI), Plaque Index (PI), Bleeding on probing (BOP) 1,2,3 and 4 weeks after insertion of the respective abutment made of three different materials

Secondary outcomes (study part 2):
For 3 years (follow-up after 4 weeks, 1, 2 and 3 years)
• Survival until abutment crown loss, continuous
• Biological and technical complications (peri-implantitis (biological), abutment loosening (technical), screw fracture (t), loss of retention (t)) and treatment failure (implant loss (b), abutment crown fracture (t))
• Clinical parameters: pocket depth TT, Gingival Index GI, Plaque Index PI, Bleeding on Probing (BOP) and Pink Esthetic Score (PES)

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Countries of Recruitment

  •   Germany
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Locations of Recruitment

  • University Medical Center 
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Recruitment

  •   Actual
  •   2014/08/25
  •   24
  •   Monocenter trial
  •   National
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Inclusion Criteria

  •   Both, male and female
  •   18   Years
  •   75   Years
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Additional Inclusion Criteria

• Patients are between 18 and 75 years of age
• Tooth space width at least 7 mm, allowing for an implant insertion before the study starts or as the case may be, state after two-stage augmentation or one-stage sinus lift or one-stage minor extend lateral augmentation
• At least 3 mm gingival height
• Legally capable patients with treatment need

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Exclusion Criteria

• Need for major extend lateral augmentation in a one-stage procedure (meaning that two-stage bone bloc surgery can be included as well as one-stage sinus lift or minor extend lateral augmentation)
• Smokers
• Implant insertion using a surgical template was impossible before the study starts
• Tooth space width is smaller than 7 mm (The interdental papilla would be severed during punch biopsy in this case)
• Less than 3 mm gingival height in the lowest most area
• Lack of informed consent
• Chronic diseases
• Pregnancy
• Alcohol- or drug abusus
• Anamnestic peculiarities, ruling out implant treatment before the study starts

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Addresses

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    • Universitätsklinikum Ulm, Zentrum für Zahn-, Mund- und Kieferheilkunde, Klinik für Zahnärztliche Prothetik
    • Mr.  Prof. Dr. med. dent.  Ralph  Luthardt 
    • Albert-Einstein-Allee 11
    • 89081  Ulm
    • Germany
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    • Universitätsklinikum Ulm, Zentrum für Zahn-, Mund- und Kieferheilkunde, Klinik für Zahnärztliche Prothetik
    • Ms.  OÄ Dr. med. dent.  Heike  Rudolph 
    • Albert-Einstein-Allee 11
    • 89081  Ulm
    • Germany
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    • Universitätsklinikum Ulm, Zentrum für Zahn-, Mund- und Kieferheilkunde, Klinik für Zahnärztliche Prothetik
    • Ms.  Dr.  Heike  Rudolph 
    • Albert-Einstein-Allee 11
    • 89081  Ulm
    • Germany
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Sources of Monetary or Material Support

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    • Universitätsklinikum Ulm /Studienleiter: Prof. Dr. Ralph G. Luthardt, Klinik für Zahnärztliche Prothetik
    • Albert-Einstein-Allee 11
    • 89081  Ulm
    • Germany
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    • Ivoclar Vivadent AG
    • Mr.  Dr.  Volker  Rheinberger 
    • Benderer Str. 2
    • 9494  Schaan
    • Liechtenstein
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Status

  •   Recruiting ongoing
  •   [---]*
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Trial Publications, Results and other Documents

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