Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05875688 |
| Other study ID # |
3363809324 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
January 6, 2019 |
| Est. completion date |
September 6, 2019 |
Study information
| Verified date |
May 2023 |
| Source |
Ziauddin University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The goal of this observational study invitro study was to compare the different cementation
techniques used to lute full veneer crowns on extracted and prepared teeth using Glass
Ionomer Cement type 1.
The main question[s] it aims to answer are:
The in-vitro effect cement application techniques on retention of full veneer crowns.
Which of the three different cementation techniques in-vitro provide a greater retention for
a full veneer crown and will it achieve better retention using the concluded method for
longer duration of cemented crown in oral cavity.
To use of adequate amount of cement to avoid wastage. The principal investigator applied the
Glass ionomer cement in three different techniques on custom prepared crowns and with the
help of an Universal Testing Machine debonded the crown from the prepared tooth. The results
were compared amongst the three categories and the technique C, proved to be the superlative
amongst the three.
Description:
1. Tooth selection The procedure started by informing the oral surgery department to
reserve mandibular premolar teeth that were being extracted each day, followed by taking
patient consent for the purpose of research. The extracted teeth collected were kept in
hydrogen peroxide for 5 minutes and then washed under tap water for any visible debris.
The teeth were then stored in Formalin 10% for a period of 7-days, as per Centers for
Disease Control and Prevention disinfection protocols. The teeth were then transported
in Hanks Balanced Salt solution to maintain disinfection and tooth quality.
2. Preparation of tooth mounts The extracted teeth were then mounted in an acrylic block
using self-cure acrylic resin (Shofu self cure acrylic resin, Japan). 0.5 mL of liquid
was dispensed into a mixing cup, then 1 g of powder was added and quickly mixed using a
spatula for 10 - 15 sec. Preformed plastic cylinders (Height; 55mm, Diameter; 20mm) were
used, and inner walls painted with petroleum jelly for easy removal. The extracted teeth
were then inserted in these cylinders filled with acrylic dough. Following
manufacturer's instructions, it was ensured that the entire procedure was completed
within 2 minutes after mixing was finished and at room temperature. The moulds were then
left for an hour at room temperature to ensure complete chemical curing.
3. Crown preparation Following complete chemical cure the teeth were prepared using a
high-speed handpiece with water irrigation with diamond bur (Head Diameter: 1.2mm, Head
Length: 7.7mm, 06-125µmm). They were first reduced in occlusal anatomical planes and a
chamfer finish line (approximately 0.75mm) was given all around. Total Occlusal
Convergence was kept at 20◦ and 25◦ with a clinical height of 5mm. Preparation
dimensions (Total Occlusal Convergence, height) of the teeth were checked using computer
software (AutoCAD 2000) after taking pictures with digital single-lens reflex camera
with 105mm lens at 100mm. The distance was reproduced using a standard metal scale. The
tooth mounts were labelled and kept in Hank's Balanced Salt Solution to maintain tissue
health. Any tooth that did not meet the preparation requirements was discarded according
to the Centers for Disease Control and Prevention criteria.
The data collection was performed by the principal investigator. Dental photograph
measurements were initially performed by the supervisor. To avoid the photographic error
the photographs were calibrated by measuring the prepared tooth and scaling it on the
AutoCAD software. The complete photography setup was stationary during the data
collection process. Then, the data between the two operators were subjected to
correlation analysis, and a strong correlation value was found (0.839). Furthermore, 20%
of photographs were then re- assessed after a period of 2 weeks by the same operator.
The data was analyzed later by formula to confirm intra-operator reliability through
correlation statistics. As proven earlier through studies by dental morphometric
measurements done by 2D image analysis can be performed by multiple operators with an
excellent reliability.
4. Crown fabrication Wax-up for metal crowns was done with metal extension (25mm), to
engage them in the Universal Testing Machine, using Dental Inlay casting wax (Inlay wax
medium stick; GC-Dental Corp. Japan). The wax up was then invested using phosphate
bonded gypsum material (GC-Super, Japan) and cast with Nickel-Chromium Ni-Cr metal alloy
at the Prosthodontics laboratory of Fatima Jinnah Dental College. The cast crowns were
then finished used metal finishing discs, making sure the metal extensions were not less
than 20mm. The fitting surface of all crowns were sandblasted accordingly and were made
ready for cementation process. The teeth were numbered between 1-120 for record purposes
and random assignment to either of the study groups.
5. Cementation Tooth mounts were randomized using their serial numbers, to either of the
three cement application techniques. This random allocation was done by generating a
random sequence using Microsoft Excel by one of the department's lecturers, not directly
related to the study. 40 teeth were allocated to each group. This sequence was passed on
to an external operator (a general dentist), again not related to the primary research
team, who was trained by the PI prior to study commencement on how to apply cement
according to the operational definitions of the three cementation techniques under
observation in this study. The cementation process started with mixing of permanent
glass ionomer type-I luting cement (3M Ketac Cem Radiopaque Hand mix, USA) according to
the manufacturer's recommendation by a single operator to ensure uniformity of mixing
technique. The liquid component of Glass Ionomer Cement was measured using a 1cc
syringe, while powder was measured using manufacturer provided scoop to ensure equal
amount of cement was mixed. The mixing was done on a glossy paper pad provided by the
manufacturer.
The external operator cemented the metal crowns on the tooth mounts according to their
allocation of cementation category. They were then seated by applying 80Newton pressure
using a hydraulic press for 10 minutes. After ensuring the cement had dried completely
the cemented crowns (on mounts) were left for seven days, soaked in distilled water to
ensure hydration and to replicate intra-oral moisture conditions.
6. Testing for retention On the eighth day, the PI undertook the experiment of retention
testing. To help in minimizing bias while performing the retention testing, the PI and
field assistant did not know which cement application technique had been used under
mounted tooth being observed. The two components (Tooth mount with cemented crown) were
then attached to a Universal Testing Machine (INSTRON-4301) and tensile forces were
applied to check the retention of the crown. The amount of force required was monitored
on the computer. The force of traction was increased slowly till the crown de-bonded and
came off the prepared tooth. That value of force in Newtons was noted in the proforma
against the tooth mount's serial number. The entire procedure was done under supervision
of a field assistant from Pakistan Council of Scientific and Industrial Research
laboratory. PI was unblinded after completion of data analysis. The serial number
allocation to study groups was directly conveyed to the statistician by the external
observer. All data were recorded in pre-formed proforma.
