Objective: Study's objectives are focused on non-invasive OCT and RX investigations, of interfaces obtained after
repairing a metal-ceramic crown with ceramic materials.
Material and method: In this study 40 metal-ceramic crowns were involved. Each crown is restoring the first central
incisor 1.1. Metallic infrastructure was performed from nickel-chrome WIRON 99 BEGO alloy, and Kiss Ceramic.
The defects of 3×3mm were created into ceramic material in the buccal-incisal area with a grinding instrument. The
samples were divided into two groups and the defects were reconstructed with two different types of ceramic
materials: Kiss and Vita Omega.
The interfaces between crown and ceramic material used for reparation were Rx and OCT investigated which are
both non-invasive, imagistic investigation techniques. For better investigation three-dimensional reconstructions
were performed.
Results: The interfaces showed defects for both systems used. Major defects such as gaps could be identified at the
ceramic-ceramic interface. Also material defects could be observed at the areas of congruence between the two
ceramic materials and smaller defects along the interfaces. The defects were present into the deep and superficial
layers of interface. The OCT system used a length wave of 1300nm and worked in B-scan mode along the interfaces
to be studied while the C-scan mode was only used at the defect areas. Rx investigation detected the macro defects.
Conclusions:
Time Domain OCT and RX systems were identifying the faulty areas after repairing artificially created defects, of
metal-ceramic crowns with ceramic material, hereby enabling us to establish recommendations for the clinical use.
Orthodontic bonding is a simple yet important procedure that can influence the outcome of treatment in case it is
performed incorrectly. An orthodontic treatment shadowed by repeated bonding failures can become unduly long and
will decrease patient trust and compliance. Optical coherence tomography has been widely used in ophtalmology but is
relatively new to dentistry. Using OCT one can detect aerial inclusions within the orthodontic adhesive or even identify
incongruence between the bracket base and the tooth surface. The aim of our study was to identify bonding defects and
reconstruct them three-dimensionally in order to be able to characterize them more accurately. We bonded 30 sound
human permanent teeth with ceramic orthodontic brackets using a no-mix self-curing orthodontic adhesive. Prior to
bonding all teeth were stored in tap water at 4°C and then professionally cleaned with rotary brushes and pumice. The
samples were processed by the same person and the rotary brushes were changed after every fifth tooth. All interfaces
were investigated by means of OCT and 4 defects were found. Subsequently, the defects were reconstructed threedimensionally
using an open-source program. By identifying and reconstructing bonding defects we could assess the
quality of the bonding procedure. Since bonding tends to be more accurate in vitro where the environmental conditions
are close to ideal, it is probable that defects found in vivo be even greater in number, which leads to the conclusion that
this type of investigation is potentially valuable.
Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in
nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or
bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material
defects inside the esthetic layers.
Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by
radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in
Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a
stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. After
detecting the presence and the positions of the ceramic defects the numerical simulation method was used to estimate the
biomechanical effect of the masticatory forces on fractures propagations in ceramic materials.
Results: For all the dental ceramic defects numerical simulation analysis was performed. The simulation of crack
propagation shows that the crack could initiate from the upper, lower or both parts of the defect and propagates through
the ceramic material where tensile stress field is present. RX and MicroCT are very powerful instruments that provide a
good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that
could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the
imagistic evaluation of the dental construct by offering important information when it is need it.
The objectives of this study are focused on non-invasive investigations of interfaces
obtained after repairing metal-ceramic crowns with ceramic repair systems. The noninvasive
systems involved in this study are OCT, SEM, AFM and RX. These
investigation systems are non-invasive and the samples are not destructed during the
investigation.
PURPOSE: The goal of our study was to investigate the changes in enamel surface roughess induced by the application
of different chemical substances by atomic force microscopy and scanning electron microscopy.
METHOD: Five sound human first upper premolar teeth were chosen for the study. The buccal surface of each tooth
was treated with a different chemical agent as follows: Sample 1 - 38% phosphoric acid etching (30s) , sample 2 - no
surface treatment (control sample), 3 - bleaching with 37.5 % hydrogen peroxide (according to the manufacturer's
instructions), 4 - conditioning with a self-etching primer (15 s), 5 - 9.6 % hydrofluoric acid etching (30s). All samples
were investigated by atomic force microscopy in a non-contact mode and by scanning electron microscopy. Several
images were obtained for each sample, showing evident differences regarding enamel surface morphology. The mean
surface roughness and the mean square roughness were calculated and compared.
RESULTS: All chemical substances led to an increased surface roughness. Phosphoric acid led to the highest roughness
while the control sample showed the lowest. Hydrofluoric acid also led to an increase in surface roughness but its effects
have yet to be investigated due to its potential toxicity.
CONCLUSIONS: By treating the human enamel with the above mentioned chemical compounds a negative microretentive
surface is obtained, with a morphology depending on the applied substance.
Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in
nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or
bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material
defects inside the esthetic layers.
Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by
radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in
Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a
stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface.
Results: RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It
is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic
crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering
important information when it is need it.
The purpose of this study is to present a non invasive method for the marginal adaptation evaluation in class V composite
restorations. Standardized class V cavities prepared in human extracted teeth were filled with composite resin (Premise,
Kerr). The specimens were thermocycled. The interfaces were examined by Optical Coherence Tomography (OCT)
combined with confocal microscopy and fluorescence. The optical configuration uses two single mode directional
couplers with a superluminiscent diode as the source at 1300 nm. The scanning procedure is similar to that used in any
confocal microscope, where the fast scanning is en-face (line rate) and the depth scanning is much slower (at the frame
rate). Gaps at the interfaces as well as on the inside of the composite resin were identified. OCT has numerous
advantages that justify its in vivo and in vitro use compared to conventional techniques. One of the main concerns was
the fact that at the adhesive layer site it was very hard to tell the adhesive apart from material defects. For this reason the
adhesive was optimized in order to be more scattering. This way we could make a difference between the adhesive layer
and the material defects that could lead to microleakages.
Fixed partial prostheses as integral ceramic, polymers, metal-ceramic or metal-polymers bridges are mainly used in the
frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress as well as esthetic
requirements. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials
defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and
phonetic disturbances which finally render the prosthetic treatment inefficient. Dental interfaces represent one of the
most significant aspects in the strength of the dental prostheses under the masticatory load. The purpose of this study is
to evaluate the capability of optical coherence tomography (OCT) to characterize the dental prostheses interfaces. The
materials used were several fixed partial prostheses integral ceramic, polymers, metal-ceramic and metal-polymers
bridges. It is important to produce both C-scans and B-scans of the defects in order to differentiate morphological aspects
of the bridge infrastructures. The material defects observed with OCT were investigated with micro-CT in order to prove
their existence and positions. In conclusion, it is important to have a non invasive method to investigate dental prostheses
interfaces before the insertion of prostheses in the oral cavity.
Standardized class V cavities, prepared in human extracted teeth, were filled with Premise (Kerr) composite.
The specimens were thermo cycled. The interfaces were examined using a system employing two simultaneous imaging
channels, an en-face Optical Coherence Tomography channel and a confocal microscopy channel.
The aim of this study was to analyze the quality of marginal adaptation and gap width of Empress veneers using
en-face optical coherence tomography. The results prove the necessity of investigating the marginal adaptation after each
veneer bonding process.
Bonding has become a routine procedure in several dental specialties - from prosthodontics to conservative dentistry and even orthodontics. In many of these fields it is important to be able to investigate the bonded interfaces to assess their quality. All currently employed investigative methods are invasive, meaning that samples are destroyed in the testing
procedure and cannot be used again. We have investigated the interface between human enamel and bonded ceramic
brackets non-invasively, introducing a combination of new investigative methods - optical coherence tomography (OCT)
and confocal microscopy (CM). Brackets were conventionally bonded on conditioned buccal surfaces of teeth The bonding was assessed using these methods. Three dimensional reconstructions of the detected material defects were developed using manual and semi-automatic segmentation. The results clearly prove that OCT and CM are useful in orthodontic bonding investigations.
The present study evaluates the potential of en-face optical coherence tomography (OCT) as a possible noninvasive high resolution method for supplying necessary information on the material defects of dental prostheses and microleakage at prosthetic interfaces. Teeth are also imaged after several treatment methods to asses material defects and microleakage at the tooth-filling interface, and the presence or absence of apical microleakage, as well as to evaluate the quality of bracket bonding on dental hard tissue. C-scan and B-scan OCT images as well as confocal images are acquired from a large range of samples. Gaps between the dental interfaces and material defects are clearly exposed.
Despite good diagnosis and treatment planning, orthodontic treatment can fail if bonding fails. It is now common
practice to address the aesthetic appearance of patients using aesthetic brackets instead of metal ones. Therefore, bonding
aesthetic brackets has become an issue for orthodontists today.
Orthodontic bonding is mainly achieved using composite resin but can also be performed with glass ionomer or resin
cements. For improving the quality of bonding, the enamel is acid etched for 30 seconds with 38% phosphoric acid and
then a bonding agent is applied. In our study we investigated and compared the quality of bonding between ceramic
brackets, polymeric brackets and enamel, respectively using a new investigation method-OCT. The aim of our study
was to evaluate the resin layer at the bracket base-tooth interface.
KEYWORDS: Laser dentistry, Pulsed laser operation, Chemical elements, Interfaces, Electrodes, Chemical species, Plasma, Metals, Chemical analysis, Medicine
The microleakage at the interface between the metal infrastructure and the veneering part of the fixed partial dentures are a common problem of aesthetic dentistry. It is possible to use the method of laser microspectral analysis for investigations of microleakage at the metal-veneering material interfaces in fixed partial prostheses. The laser microspectral analysis device LMA-10 (Carl Zeiss, Jena) was used equipped with a diffraction spectrometer PGS-2 (Carl Zeiss, Jena). Different fixed partial dentures were used to determine the microleakage between the metal infrastructure and the veneering material. The distribution of chemical elements at interface infiltration was investigated, making a series of craters and establishing the spectra of the vapours emitted from the craters. Data was gathered in various tables of chemical elements showing the quality and the quantity of microleakage. The laser microspectral analysis is a punctual method of analysis, which allows to investigate small quantities of materials of around 0.1 μg. This method allows to establish the content of atoms and molecules and to perform semi-quantitative and quantitative analysis. By this method it is possible to establish trace elements, i. e. with concentration of ppm (parts per million).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.