Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT06463405 |
| Other study ID # |
REPLACE |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
March 1, 2024 |
| Est. completion date |
January 31, 2028 |
Study information
| Verified date |
June 2024 |
| Source |
University of Copenhagen |
| Contact |
Chahak Seth-Johansen, DDS |
| Phone |
+4551410210 |
| Email |
chahak.seth[@]sund.ku.dk |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The overall aim is to evaluate the patient-reported outcome and efficiency of replacing
posterior teeth with implant-supported crowns compared to RDPs and no treatment. Sub-aims are
to evaluate a new 3D-methods for registration of occlusion and to test two crown designs.
Thus, the study design has three aims:
- To analyze patient perception including OHRQoL, when missing posterior teeth are
replaced with implant-supported crowns compared to removable dental prostheses (RDPs) or
no replacement.
- To develop and validate new 3D digital methods for assessing occlusal contacts between
upper and lower jaw and to analyze the methods relation to masticatory ability and
efficiency.
- To compare the difference in biological technical outcomes between splinted and
non-splinted implant-supported crowns over time.
Description:
Hypotheses
- No difference in patient perception of mastication and OHRQoL between no treatment, RDPs
and implant-supported crowns in the posterior region
- No difference between two different digital techniques (T-scan and 3D Intraoral
scanning) in measuring the occlusal contact points and area.
- No difference in biological and technical outcomes between splinted and non-splinted
implant-supported crowns
Material and methods. Participants Partially edentulous subjects with missing posterior teeth
(Kennedy class I or class II) in the upper or lower jaw, in need for fixed implant-supported
crowns to replace the missing teeth are offered to be enrolled if they fulfill the following
inclusion criteria. The participants must be in good health and with no contraindications for
undergoing dento-alveolar surgery.
Subjects presenting with the following conditions will be excluded from the study:
- Untreated or active, progressive periodontitis
- Intake of (high dose) antiresorptive medicine or earlier medication related
osteonecrosis of the jaw
- Therapeutic radiation to the head and neck
- Uncontrolled diabetes or systemic corticosteroids
- Heavy smoking (>20 cigarettes/day)
- An inability to open the mouth wide enough to place implants
- Decayed or unrestored anterior/premolar teeth
- Need for major bone augmentation (e.g., bone block graft, extensive augmentations with
second operation for implant insertion)
- < 8 mm bone height to the alveolar nerve or sinus maxillaris
- Parafunctional habits or untreated temporomandibular dysfunctions or orofacial pain
- Unable to cooperate or too ill to complete the experiment
- Lack of signed informed consent A participant, who no longer wishes to participate in
the trial, can withdraw her/his informed consent at any time. Withdrawn subjects can
give information of which aspects of the trial she/he wishes to withdraw from.
All included subjects must have a natural dentition or fixed implant-supported
reconstructions in the opposite jaw of at least two premolar equivalents occluding against
the planned implant-supported crowns. If the teeth in the opposing jaw are elongated a
coronal reduction will be performed to create unequivocally occlusal plane.
Free-end dentitions with missing teeth behind the canine, 1 or 2 premolars can be included.
Patients from the dental school as well as patients from private practice will be invited to
participate in the study when funding is achieved.
Pre-examinations and methods Participants will be pre-examined to be sure the inclusion and
exclusion criteria is full filled (Figure 1). A Panoramic X-ray will be used to screen the
tooth- and periodontal status. If these are full-filled a tempomandibular disorder pain
screening (TMD) will be performed. Followed by the Nordic Orofacial Test Screening (NOT-S).
A Cone Beam CT (CBCT) scanning of the regions for implant placement will be performed using a
Planmeca Viso 3D scanner; 100 kV, 12mA, voxel size 150 µm) with a FOV of 5 x 5 cm in both
sides of the jaw for Kennedy class I dentition and in one side of the jaw for Kennedy class
II dentitions.. This is estimated to give radiation of 2 x 50 µSv (Kennedy class 1 dentition)
or 1 x 50 µSv, which is equivalent to a 7 hour t/r (Kennedy class 1 dentition) or a one way
(Kennedy class 2 dentition) flight trip to New York in 10 km height.
T-scan (Tek-scan) and IOS-scan will be performed according to the description from the
companies and OCA´s will be calculated.
Primary outcomes: Questionnaires on oral health and chewing Oral health Impact Profile 14,
DC/TMD-screening test, Nordic Orofacial Screening test, Stellingsmas chewing ability
questionnaire.
Secondary outcomes: Bite force and muscle strength Maximum bite force, tooth contact in
intercuspal position, chewing time measurements and electromyography will be performed
according to earlier descriptions.
The force during maximum tooth clenching will be recorded for 1 to 2 seconds with a
strain-gauge transducer placed unilaterally on the mandibular first premolars. The transducer
will be covered with protective plastic tubes and connected to an amplifier with peak storage
facility. The molar bite force (N) will be assessed as the average of the stored peak values
from right and left side (2 at each side with intervals of about 0.5 min).
EMG activity will be acquired bilaterally from the anterior temporal and masseter muscles
during 1 to 2 seconds of maximal biting in the intercuspal position in 2 epochs with 1 min
apart by means of a custom-designed 8-channel EMG system after amplification and filtering
(gain 500-10,000; high-pass filter at 20-50 Hz and low pass at 1 kHz). The recordings will be
performed with reusable, bipolar surface electrodes (tin plates, 3.0 x1.5 x 10.0 mm and 10-mm
distance between electrodes) covered with electrode paste. After cleaning the skin with
alcohol to reduce impedance, the electrodes will be placed transversely to the fiber
direction.
Masticatory performance The chewing efficiency will be measured by the apple chewing time
(seconds) as the duration of the chewing of a standardized slice of green, crisp apple (11 g
Granny Smith with rind and core removed) from the first bite to the spontaneous termination
swallow.
Also, the duration of the chewing cycle (milliseconds) during chewing of apple slices will be
assessed by EMG from the average of 5 strokes in 2 chewing sequences measured automatically
by the EMG system with the right anterior temporal muscle as reference muscle (definition of
chewing cycle: from the start temporal activity of one closing phase to the start of temporal
activity in the next closing phase).
Occlusal tooth contact The contact will be recorded clinically for all teeth and
restorations. The contact was rated as 'firm' when the patient was able to maintain a
straight plastic strip (0.05 x 6 mm) between the teeth against a strong pull, as 'near'
contact if the strip could be pulled out but with resistance, and 'no' contact if there was
no resistance to the pull. The contacts will be converted to occlusal units measures in
premolar equivalent.
Ethical and data collection approval The project will be sent for approval at the local
ethical committee. All procedures in the study will be conducted according to the 1964
Helsinki Declaration and its later amendments. Informed consent will be obtained from all
participants included in the study on a written form approved by the Ethical Committee of the
Medical Faculty at Copenhagen University. Participants will be informed about the risks of
and alternatives to the proposed therapy.
Approval from Faculty of Health and Medical Sciences, Copenhagen University for processing of
personal data (Case no 514-0798/23-3000).
Outcomes The primary clinical outcome of the first part of the study are OHRQoL measured with
the validated Oral Health Impact Profile (OHIP-14) formula. It consists of 14 items rated in
frequency on a Likert scale with five response options and according to score: very often
(4), fairly often (3), occasionally (2), hardly ever (1), never (0) or don't know. Thus, an
overall score between 0 and 56 can be obtained. A low score indicates good OHRQoL. The
OHIP-14 patient questionnaire will be collected from the patients before and 1 month after
the treatment with implant-supported crowns, bilaterally. Furthermore after 3- and 5-years
follow-up.
The masticatory function in the first part of the study will be assessed with masticatory
ability questionnaires and masticatory efficiency tests. Masticatory ability will be tested
using the chewing ability questionnaire developed by Stellingsma and co-workers. In the
questionnaire, the participants give their opinion about their ability to chew nine different
kinds of food on a VAS scale. The items will be grouped into three scales A: soft food
(boiled vegetables and potatoes, crustless bread, minced meat); B: tough food (crusty bread,
steak, Gouda cheese) and C: hard food (apple, carrot, peanuts). The chewing time from putting
the nine food items into the mouth and until swallowing will be measured in minutes and
seconds with and without removable dental prosthesis (RDP) and 1 month after treatment with
implant-supported crowns (ISC). The same intervals as above will be used for the bite force
measurements and the occlusal contact area (OCA) (T-scan or Intraoral scanner) i.e., with
(TRDP) and without (T0) RDPs and 1 month (T1) after treatment with ISC.
The maximum bite force will be measured using a U-shaped bite force transducer displaying
force ranging from 0 -1000 (Kgf). The participants will be asked to clench their teeth for 5
s and the highest bite force displayed was noted as their peak value. The test will be
repeated four times. Maximum bite force was measured initially in the session and the
participants were given a two-minute rest before the next test was commenced.
In the second part of the study 2 digital methods for recording occlusal contacts will be
examined and correlated to the conventional analog occlusal contacts registration with foils.
Occlusal contact area: The first method used to obtain an occlusal record will be the digital
Tekscan (Tekscan Inc. Boston, MA). Each participant will be instructed in occlusion in the
intercuspal occlusion position (IP) 3 times using maximum occlusal force and with a 100 my
thick sensor foil placed in situ e.g., between the upper and lower jaw in IP. The T-scan
software will generate a dynamic report showing an occlusal image of the relative bite force.
One image of the 2D occlusal picture at maximum force and 2 other images at approximately 50%
of the maximum force will be captured to compare occlusal registration at different clenching
levels. The force will be determined by using a bite force measurement (Bite force equipment,
Oslo, Norway) in the first premolar area. Each image will be coded and analyzed using
computer software (Image J, NIH, US).
The second method of occlusal contact area will be assessed using a 3D intraoral digital
scanner (IOS). Teeth in the maxillary and mandibular dental arch will be scanned intraorally
and the relationship between the jaws will be registered by scanning the intercuspal occlusal
position in both sites of the jaws. The IOS software will capture the scans and 2D pictures
of the occlusal picture by normal intercuspal force (approximately half of the maximum bite
force). An occlusal view of the 3D models will be selected, and the software will be
programmed for automatic selection of the occlusal contact area (OCA).
The third method of describing the mandible jaw contact to the maxillary jaw is by occlusal
units measured in premolar equivalent. This quite simple method is the most frequently used
in the clinic. With 28 teeth the subject can have 18 occlusal pairs as the molars counts for
two premolars. Clear shim stock foils are placed between the teeth and occlusal contact
selection is based on an operator´s "resistance feel", when pulling the foil out from
opposing occluding teeth. This is also called a static occlusal indicator and is the
conventional method for occlusal contact registrations.
The third part of the study will compare splinted versus non-splinted crowns in a randomized
design. Whether the crowns will be splinted or not are decided by distant randomization
separate from clinicians conducting the trial. Twenty sealed envelopes will be opened where
its stands whether the crowns has to be splinted crowns or non-splinted crowns. The implants
in the splinted side will have an intermediate titanium abutment and impression will be taken
at abutment level, whereas impressions in the non-splinted side will be taken directly at the
fixture level. The splinted as well as the non-splinted crowns will be screw-retained and
produced in monolithic zirconia. An open-tray technique / (scanning) will be used for both
reconstructions.
The implant-supported reconstructions will be examined 1 month after insertion (baseline
examination) and at 1-, 3- and 5-years follow-up examinations. At the baseline the former
described methods for oral function and oral OHRQoL will be done, and biological and
technical variables will be added. Marginal fit as well as other quality parameters of the
reconstruction will be evaluated with the Copenhagen index score as well as an accessibility
for oral hygiene score, Bleeding on probing (BOP), modified Gingival and plaque index as well
and the incidence of mechanical complications including screw loosening's and ceramic
chippings will be undertaken at baseline, 1-, 3- and 5-years follow-up examinations.
The marginal bone level will be evaluated at intraoral radiographs at the same intervals
using customized radiographic positioning jigs to obtain periodically "identical"
radiographs. Changes in marginal bone level (marginal bone loss, MBL) will be measured and
calculated, and MBL will be the primary outcome variable for this part of the study.
Statistical analysis Using a significance level of 5% and a power of 90% with an improvement
in Oral Health Related Quality of Life (OHIP-14) for 80% of the participants, (OHIP-14 change
score > 2) the study will need 18 subjects. With a drop-out of five, 23 subjects in the upper
or lower jaw are endeavored.
The data will be presented descriptively using mean and standard deviations to clarify small
differences and to make comparison with other studies. Difference between groups in the
outcome variables over time will be analyzed with linear mixed model. The tests will be
performed by a statistician using the statistical program R and/or SPSS statistical software.
A p-value of 0.05 or lower will be considered as statistically significant.
