Dental shade determination and seamless integration of restorative work in the oral cavity are challenging and important tasks in the everyday clinical dental practice. The aim of this in-vitro study was to evaluate comparatively the capability of software-based color analysis of mobile phone photography, with the spectrophotometric and visual methods for dental shade determination. Visual shade determination of the incisal, middle, and cervical thirds parts of ten extracted human teeth was performed using the Vita Classical and Vita 3D Master stock shade guides. Shade determination of the thirds of each tooth was performed using the Vita Easyshade spectrophotometer. Subsequently, photographs of each tooth were captured using a mobile phone camera. Color charts were produced using an in-house image processing technique, and the tooth color captured by the mobile phone photography was matched to the shade guides. The results show that the camera-based method had better agreement with the spectrophotometric and visual methods when the Vita Classical shade guide was employed. Software-based color analysis of mobile phone photography should be further explored for its use as an affordable potential tool for increasing objectivity and accuracy in dental shade determination.
The formation of dental biofilm follows specific mechanisms of initial colonization on the surface, microcolony
formation, development of organized three dimensional community structures, and detachment from the surface.
The structure of the plaque biofilm might restrict the penetration of antimicrobial agents, while bacteria on a surface
grow slowly and display a novel phenotype; the consequence of the latter is a reduced sensitivity to inhibitors. The
aim of this study was to evaluate with different optoelectronic methods the morphological characteristics of the
dental biofilm.
The study was performed on samples from 25 patients aged between 18 and 35 years. The methods used in this
study were Spectral Domain Optical Coherence Tomography (SD-OCT) working at 870 nm for in vivo evaluations
and Scanning Electron Microscopy (SEM) for validations. For each patient a sample of dental biofilm was obtained
directly from the vestibular surface of the teeth's.
SD-OCT produced C- and B-scans that were used to generate three dimensional (3D) reconstructions of the sample.
The results were compared with SEM evaluations. The biofilm network was dramatically destroyed after the
professional dental cleaning.
OCT noninvasive methods can act as a valuable tool for the 3D characterization of dental biofilms.
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.
There are several methods known which are used to assess the quality of direct dental restorations, but most of them are
invasive. These lead to the destruction of the probes and often no conclusion could be drawn in respect to the existence
of any microleakage in the investigated areas of interest.
Optical tomographic techniques are of particular importance in the medical imaging field, because these techniques can
provide non-invasive diagnostic images. Using an en-face version of OCT, we have recently demonstrated real time
thorough evaluation of quality of dental fillings.
The purpose of this in vitro study was to validate the en face OCT imagistic evaluation of direct dental restoration by
using scanning electron microscopy (SEM) and microcomputer tomography (μCT). Teeth after several treatment
methods are imaged in order to detect material defects and to asses the marginal adaptation at the dental hard tissue
walls.
SEM investigations evidenced the nonlinear aspect of the interface between the filling material and the buccal and
lingual walls in some samples.
The results obtained by μCT revealed also some material defects inside the fillings and at the interfaces with the rootcanal
walls.
The advantages of the OCT method consist in non-invasiveness and high resolution. En face OCT investigations permit
to visualize a more complex stratificated structure at the interface filling material/dental hard tissue and in the apical
region.
Successful root canal treatment is based on diagnosis, treatment planning, knowledge of tooth anatomy, endodontic
access cavity design, controlling the infection by thorough cleaning and shaping, methods and materials used in root
canal obturation. An endodontic obturation must be a complete, three-dimensional filling of the root canal system, as
close as possible to cemento-dentinal junction, without massive overfilling or underfilling.
There are several known methods which are used to assess the quality of the endodontic sealing, but most are invasive.
These lead to the destruction of the samples and often no conclusion could be drawn in respect to the existence of any
microleakage in the investigated areas of interest. Using an time domain en-face OCT system, we have recently
demonstrated real time thorough evaluation of quality of root canal fillings.
The purpose of this in vitro study was to validate the en face OCT imagistic evaluation of endodontically treated human
teeth by using scanning electron microscopy (SEM) and microcomputer tomography (μCT).
SEM investigations evidenced the nonlinear aspect of the interface between the endodontic filling material and the root
canal walls and materials defects in some samples.
The results obtained by μCT revealed also some defects inside the root-canal filling and at the interfaces between the
material and the root canal walls.
The advantages of the OCT method consist in non-invasiveness and high resolution. In addition, en face OCT
investigations permit visualization of the more complex stratified structure at the interface between the filling material
and the dental hard tissue.
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.
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