The authors have none to acknowledge.

The protocol involves standardized documentation of patients&#39; clinical presentation as routinely administered at Columbia University College of Dental Medicine, New York. No patient data were utilized for this publication; the co-authors R.B and J.M.D.O are depicted in the photographs themselves, illustrating techniques described in this protocol and providing consent to publish the images involved. Replicating the procedure under clinical settings will require written informed consent from the patients.
1. Acquisition of extra-oral photographs
<ol>
	<li>Utilize a ring flash and an extra-oral photography reflector (see Table of Materials) for extra-oral photography.</li>
	<li>Acquire patient&#39;s extra-oral photos with a black background. Use a black velvet cloth for the background to reduce shine or unwanted reflections. 
	NOTE: Alternatively, a white background is acceptable as well. It is recommended that the patient be positioned away from external sources of light (i.e., sunlight through a window).</li>
	<li>Ask the patient to remove the eyewear so that both ears are equally visible. 
	NOTE: Individuals with long hair must tuck their hair behind the ear.</li>
	<li>Position the patient straight across the photographer against the background. Align the patient&#39;s head to ensure that the interpupillary line is parallel to the horizontal frame of the camera viewfinder. 
	NOTE: The photo needs to compromise the superior portion of the patient&#39;s head, and the inferior portion needs to encompass the area just below the thyroid gland (Figure 3A).</li>
	<li>For standard documentation purposes, position the patient at a 90&#176; angle and capture the straight frontal photo and the right-side profile photos (Figure 3B). 
	&#8203;NOTE: Additionally, one may consider adding a left and right photo acquired at a 45&#176; angle for esthetic cases (Figure 3C).
	<ol>
		<li>For each position, consider acquiring three poses: repose, natural smile, and widest smile1,17.</li>
	</ol>
	</li>
</ol>
2. Acquisition of intra-oral photographs
<ol>
	<li>Ask the patient to sit in a dental chair at a 45&#176; inclined position (Figure 4A). Ensure that the photographer is at the patient&#39;s 9 o&#39;clock position with the armamentarium for photography (see Table of Materials) located within arm&#39;s reach. 
	NOTE: Figure 4B illustrates the viewfinder observed in the cameras. They are employed to center the image captured where the image is centered to the middle of the viewfinder (Figure 4C).</li>
	<li>Turn off the dental operatory light to prevent light interference with the photos.</li>
	<li>Acquire frontal photos following the steps below.
	<ol>
		<li>Position the patient in maximal inter-cuspal position (M.I.P.)15.</li>
		<li>Place and position the retractors intra-orally into the mouth and recruit the patient to hold the retractors (Figure 4D).</li>
		<li>Position the operator such that the plane of occlusion of the camera is parallel to the horizontal frame line in the camera&#39;s viewfinder (Figure 4E,F). 
		NOTE: Incorrect position of the retractors can result in distorted images where the capture of the soft tissues can be incomplete (Figure 4G). The resultant images do not represent the entire oral cavity when the occlusal plane is not parallel to the operator. Figure 4H,I demonstrates the effect of operator position on the image acquired.</li>
	</ol>
	</li>
	<li>Acquire buccal left and right intra-oral photos.
	<ol>
		<li>Align the patient&#39;s head toward the operator. For acquiring photos on the patient&#39;s right side, place the retractor in the left side of the patient&#39;s mouth. 
		NOTE: The retractor needs to be placed at the angle of the patient&#39;s mouth without tension (Figure 5A,C).</li>
		<li>Utilize the narrow mirror (see Table of Materials) for the buccal photos. Warm the mirror with a commercially available blow torch before insertion (Figure 5B).</li>
		<li>Insert the mirror into the patient&#39;s mouth parallel with the occlusal plane, gently move to the left buccal vestibule, and rotate 90&#176;. 
		NOTE: The mirror&#39;s edge must be rested gently on the external oblique ridge (Figure 5E,F).</li>
		<li>Use the mirror to stretch the patient&#39;s cheek and, at the same time, reveal a reflection of the buccal surface of the right maxillary and mandibular posterior dentition. Apply the same for the left side.</li>
	</ol>
	</li>
	<li>Acquire occlusal intra-oral photographs.
	<ol>
		<li>Position the retractor in the patient&#39;s mouth. Use the large mirror (see Table of Materials) for capturing this photo. 
		NOTE: The patient is recruited to aid in retracting to reveal the maxillary dentition and the buccal vestibule (Figure 6A).</li>
		<li>Before insertion, warm the mirror using a Bunsen burner and insert it into the patient&#39;s mouth. Request the patient to open the mouth as wide as possible to reveal the entire maxillary dentition from molar to molar in the maxillary (Figure 6B).</li>
		<li>For mandibular occlusal photos, change the retractor positions appropriately to reveal the mandibular dentition and associated buccal vestibule (Figure 6D). Request the patient to roll their tongue to the back of the mouth to show the floor of the mouth (Figure 6F). Warm up the occlusal mirror and subsequently insert it gently against the ventral surface of the tongue.</li>
	</ol>
	</li>
	<li>Acquire lingual intra-oral photographs.
	<ol>
		<li>To view the maxillary palatal sextants15 (Figure 7A), use the retractor to retract the left or right maxillary lip. Warm up the small mirror, insert it in the patient&#39;s mouth, and position it to reveal the palatal surface and the palatal mucosa (Figure 7B).</li>
		<li>To view the mandibular palatal sextants15 (Figure 7C), warm up the small mirror and insert it between the tongue and the lingual surfaces of the mandibular dentition. Gently align the mirror medially to reveal the reflection of the lingual surface of the dentition.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Wagner, D. J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=beginning+guide+for+dental+photography:+a+simplified+introduction+for+esthetic+dentistry.">beginning guide for dental photography: a simplified introduction for esthetic dentistry.</a> Dental Clinics of North America. 64 (4), 669-696 (2020).</li><li>Fung, L., Brisebois, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementing+digital+dentistry+into+your+esthetic+dental+practice.">Implementing digital dentistry into your esthetic dental practice.</a> Dental Clinics of North America. 64 (4), 645-657 (2020).</li><li>Kalpana, D., Rao, S. J., Joseph, J. K., Kurapati, S. K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.">Digital dental photography.</a> Indian Journal of Dental Research. 29 (4), 507-512 (2018).</li><li>Wander, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dental+photography+in+record+keeping+and+litigation.">Dental photography in record keeping and litigation.</a> British Dental Journal. 216 (4), 207-208 (2014).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+1:+an+overview.">Digital dental photography. Part 1: an overview.</a> British Dental Journal. 206 (8), 403-407 (2009).</li><li>Hodson, T. M., Donnell, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colour+fidelity:+the+camera+never+lies+-+or+does+it.">Colour fidelity: the camera never lies - or does it.</a> British Dental Journal. 229 (8), 547-550 (2020).</li><li>Morse, G. A., Haque, M. S., Sharland, M. R., Burke, F. J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+clinical+photography+by+U.K.+general+dental+practitioners.">The use of clinical photography by U.K. general dental practitioners.</a> British Dental Journal. 208 (1), 1 (2010).</li><li>Whitehouse, W., Silva, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Full frame vs. crop sensor: Which format is best for you. , (2022).</li><li>Sajjadi, S. H., Khosravanifard, B., Moazzami, F., Rakhshan, V., Esmaeilpour, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+three+types+of+digital+camera+sensors+on+dental+specialists'+perception+of+smile+esthetics:+a+preliminary+double-blind+clinical+trial.">Effects of three types of digital camera sensors on dental specialists' perception of smile esthetics: a preliminary double-blind clinical trial.</a> Journal of Prosthodontics. 25 (8), 675-681 (2016).</li><li>Moussa, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+dental+photography:+professional+vs.+smartphone's+camera.">Accuracy of dental photography: professional vs. smartphone's camera.</a> BioMed Research International. 2021, 3910291 (2021).</li><li>Liu, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Dental Digital Photography. , 1622-1627 (2019).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+5:+lighting.">Digital dental photography. Part 5: lighting.</a> British Dental Journal. 207 (1), 13-18 (2009).</li><li>Desai, V., Bumb, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography:+a+contemporary+revolution.">Digital dental photography: a contemporary revolution.</a> International Journal of Clinical Pediatric Dentistry. 6 (3), 193-196 (2013).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+6:+camera+settings.">Digital dental photography. Part 6: camera settings.</a> British Dental Journal. 207 (2), 63-69 (2009).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+8:+intra-oral+set-ups.">Digital dental photography. Part 8: intra-oral set-ups.</a> British Dental Journal. 207 (4), 151-157 (2009).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+10:+printing,+publishing+and+presentations.">Digital dental photography. Part 10: printing, publishing and presentations.</a> British Dental Journal. 207 (6), 261-265 (2009).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+7:+extra-oral+set-ups.">Digital dental photography. Part 7: extra-oral set-ups.</a> British Dental Journal. 207 (3), 103-110 (2009).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+2:+purposes+and+uses.">Digital dental photography. Part 2: purposes and uses.</a> British Dental Journal. 206 (9), 459-464 (2009).</li><li>Grundy, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+influencing+innovation+in+general+dental+practice.">Factors influencing innovation in general dental practice.</a> British Dental Journal. 153 (10), 353 (1982).</li><li>Ahmad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dental+photography.+Part+3:+principles+of+digital+photography.">Digital dental photography. Part 3: principles of digital photography.</a> British Dental Journal. 206 (10), 517-523 (2009).</li></ol>

The authors have no conflicts of interest to disclose.

Traditional evaluation tools in dentistry such as periodontal charting and model impressions of the oral dentition used for generations consistently provide clinical data; however, they have limitations16. Several clinical pathologies and soft tissue presentations are not accurately represented in traditional modalities of dental evaluation. Thereby, electronic documentation via dental photography is now considered a valuable tool. The clinical photographs reveal the patient&#39;s current...

The approach to the clinical practice of dentistry has evolved over the decades to include a conceptual framework of clinical reasoning based on empirical evidence1. As such, digital documentation now serves as an integral part of the framework on which clinical decisions are made, and evolution of care is observed2. The purpose exceeds mere primary legal records and now encompasses a plethora of extensions that include active mode of communication with patients, educational tools for dental members, educators, and colleagues, visual aids for technicians, and finally, effective marketing3.
Dental photography is often mistakenly construed as technically challenging and plagued with hurdles4. Clinicians find incorporating dental photography to be laborious, an additive task to an already complex series of events that generally occur during patient consultations or treatment. Capturing the essence of a treatment can be technically daunting, especially when it involves purchasing a series of equipment and assembling them further. Even more, the tandem application of the equipment and initial learning curve has been known to deter clinicians from adopting this modality routinely. Additionally, clinicians who overcome the initial intimidation find themselves wrought with the intricacies of the environment they are capturing. The oral cavity has several movable and fixed components. The different fields of view, tissue hydration levels, range of access limited by the patient range of opening, and different clinical presentations are a few obstacles to mention. When these get coupled together with already existing, established photography equipment, the task of utilizing photography as a tool is not a priority for clinicians5. However, with recent advances in technology, clinicians can hugely benefit from adopting dental photography, not merely for educational and clinical decisions, but patient treatment visualization and satisfaction through digital smile design6. Incorporating digital records can enhance the planning and execution of complex treatment plans. The standardization of these records allows for direct comparison before and after series, and fosters a digital fingerprint of dental records that captures a patient&#39;s clinical footprint in time7.
The proposed manuscript aims to standardize the approach to dental photography while illustrating the technical aspects and simplifying the methodology to allow clinicians at different levels to adopt and incorporate photography to increase productivity and achieve success. Furthermore, the manuscript illustrates techniques to practice dental photography without the aid of an assistant, in minimal space with inexpensive equipment and constricted areas.
Camera and supporting infrastructure for enhanced digital photography
Camera 
Several different cameras are available for dental photography; however, a digital single-lens reflex (DSLR) or a mirrorless camera is recommended. There are two types of DSLR or mirrorless cameras. A full-frame camera has a sensor size of 36 mm x 24 mm, and a crop-frame 22 mm x 14 mm8 (Figure 1A). For dental photography purposes, crop frame sensors are recommended due to the superior depth of view compared to a full-frame camera9. Depth of view is the distance between the closest and the furthest point in a picture that noticeably appears clear and focused (Figure 1B). Mobile phone cameras are not recommended for routine dental photography. The cameras lack the necessary settings (aperture) to produce adequate intra-oral photographs. Compact cameras, in general, have a micro 4/3 lens. The lens in these cameras is fixed and not interchangeable10. Dental photography explicitly demands a macro lens for enhanced image capturing.
Lens 
A macro lens has the capability of producing proportional images. The observed 1:1 ratio in the lens context is defined as an image observed by a clinician that is reproduced on the camera sensor and therefore captured in a photograph. Telephoto lenses are zoom lenses; one may get distortions incorporated into an image with zoom11. In a dental photograph, oral structures need to be reproduced as accurately as they appear in the patient&#39;s oral cavity, and therefore, macro lenses are well suited for this purpose. Many different macro lenses are available, which differ in focal lengths. A focal length of 85-105 mm is recommended. When acquiring photos, the lens allows one to be in close range with the patient&#39;s anatomy without being too close to the patient during photography (Figure 1C).
Flash 
There are two kinds of camera flashes available. One is mounted on the camera, and the other is a studio strobe light. For dental photography purposes, the former is recommended12. Several such systems are available, producing different lighting effects, influencing the quality of photographs obtained. For simplicity purposes, a ring flash is recommended to be mounted onto the camera.
Mirrors 
Intra-oral mirrors are an essential tool. They permit the capture of specific segments of the oral cavity that are challenging to capture otherwise. Rhodium-coated mirrors are recommended for their enhanced image quality and physiologically accurate clarity13. Alternatively, titanium or steel mirrors set up are employable since they are more durable. However, they do produce images of diminished quality.
Retractors 
These are necessary to allow unimpeded access to the oral cavity structures. Rounded-shaped retractors are recommended as they are easy to implement and allow full retraction of extra-oral structures.
Reflector 
A photographic reflector is recommended since it helps to illuminate the lower mandibular area in an extra-oral portrait photograph, as the site is commonly influenced by shadows.
Others 
Air syringes are commonly used for de-fogging of intra-oral mirrors. A torch is recommended to warm up the mirrors. This ensures that one can capture an image with very little to no help from a second person.
Camera settings and recommendations for intra- and extra-oral photography 
To allow complete control of the camera settings (described below), the camera needs to be set at manual mode and single shot (Figure 2D).
ISO 
ISO translates to how sensitive a camera sensor is to receiving light (Figure 2A). The higher the ISO, the more sensitive the sensor is to receiving light. This, however, is inversely proportional to the image quality obtained. For dental photography purposes, the recommended ISO needs to be set at 100-40014,15 (Figure 2B and Table 1).
Shutter speed 
Shutter speed refers to how fast a camera shutter responds to enable the sensor to capture an image (Figure 2C,D, and Table 1). The recommended shutter speed needs to be set at 1/125 for intra- and extra-oral photography for dental photography purposes14.
Aperture/F-stop 
F-stop refers to the dimensions of opening by the diaphragm of the macro lens. The lower number corresponds to a wider diaphragm opening, resulting in a shallow depth of view. For dental photography purposes, an aperture of F29-32 is recommended for intra-oral photography and F9-11 for extra-oral photography14,15 (Figure 2E-G and Table 1).
White balance 
White balance is defined as the camera sensor&#39;s ability to compensate for color biases influenced by the external light source. For example, an image acquired in the office with yellow light will present warm undertones. The white balance in dental photography needs to be maintained at 5,500 K to obtain physiological representative images14.
Lighting 
Adequate illumination is necessary to acquire physiologically representative images of the oral cavity. The higher the flash ratio (1:1), the stronger the flash output. For dental photography, the illumination on the flash needs to be set at 1:4 or 1:8 ratio since the F-stop is established at 29-3215.
Picture settings 
The picture settings refer to the camera body preset settings for image contrast and saturation. Different settings result in different camera picture styles. Standard or neutral settings are preferred to accurately represent the oral tissues&#39; physiological presentation. Image quality needs to be set at R.A.W. + JPEG fine16. These settings are used to even out high contrast images by selectively adjusting the highlights and shadows. However, an accurate representation of the patients&#39; oral tissues is desired without artificial modification for dental photography purposes.

<table><tbody><tr><td>Armamentarium for photography</td><td></td><td></td><td></td></tr><tr><td>Buccal Mirror #15- Narrow mirror</td><td>Doctoreyes</td><td>Ultrabright #15</td><td>Width 40 mm with ultrabright coating</td></tr><tr><td>Camera</td><td>Nikon</td><td>D7500</td><td></td></tr><tr><td>Occlusal Mirror #13- Large Mirror</td><td>Doctoreyes</td><td>Ultrabright #13</td><td>Width 70 mm with ultrabright coating</td></tr><tr><td>Ring Flash</td><td>YongNu</td><td>Macro ring lite YN14EX</td><td></td></tr></tbody></table>

a standardized approach to extra-oral and intra-oral digital photography

Contemporary dentistry mandates a more comprehensive and personalized analysis of each patient. Technological advances in digital photography have played vital roles in diagnostic accuracy, treatment planning, execution of therapies, and outcome evaluations, including esthetic enhancement. Digital photography also provides an excellent platform for patient education, communication, and co-management of cases with other healthcare providers. However, intra-oral photography often faces challenges such as inaccessibility of areas to be captured, different moveable vs. fixed tissues involved, contamination with saliva or blood, and differing illumination needs on various locations. Thus, a more standardized and systematic approach is proposed for intra- and extra-oral documentation via digital photography to overcome the existing technical challenges. The current work will outline the appropriate equipment specifications (camera bodies, macro lens, and flashes), positions and postures of the operator and patients, proper techniques of tissue retraction, the use of appropriate intra-oral mirrors, and the essential elements such as aperture settings (F-stop), ISO, shutter speed, and white balance. This article aims to provide all dental professionals with an approachable linear array of guidelines to produce simplified and standardized visual tools for more efficient and effective documentation.

Techniques illustrated in the protocol section were employed to acquire a sequence of extra- and intra-oral photographs. Figure 8A demonstrates the patient in different positions. The three composite positions include repose, natural smile, and widest smile. The photographs are taken in the suggested composite positions to illustrate the facial changes observed in the patient while in function. The musculature surrounding the oral cavity is influenced by restorative work performed in the ora...

Watch this Scientific Journal Video about A Standardized Approach to Extra-Oral and Intra-Oral Digital Photography at JoVE.com

A Standardized Approach to Extra-Oral and Intra-Oral Digital Photography

The present protocol describes a method to capture intra- and extra-oral photographs for digital documentation in the clinical practice of dentistry. The protocol highlights all the critical components involved and the commonly utilized settings to capture dental photographs for clinical documentation.

Contemporary dentistry mandates a more comprehensive and personalized analysis of each patient. Technological advances in digital photography have played ...

a-standardized-approach-to-extra-oral-intra-oral-digital

Research

JoVE Journal

Medicine

7.2K Views.  Columbia University College of Dental Medicine. We streven naar een gestandaardiseerde en systematische aanpak voor intra- en extra-orale documentatie via digitale fotografie. Een digitale documentatietechniek die vereenvoudigde methodologie omvat die gemakkelijk te adopteren, reproduceerbaar en routinematig kan worden opgenomen in de dagelijkse klinische praktijk. Het doel van deze techniek is niet alleen voor medische juridische dossiers.Foto's zorgen ook voor een effectievere communicatie tussen behandelaars en patiënten. Dit ve...

Video: A Standardized Approach to Extra-Oral and Intra-Oral Digital Photography

Measuring the Complete-arch Distortion of an Optical Dental Impression

Digital workflows have actively been used to produce dental restorations or oral appliances since dentists started to make digital impressions by acquiring 3D images with an intraoral scanner. Because of the nature of scanning the oral cavity in the patient&#39;s mouth, the intraoral scanner is a handheld device with a small optical window, stitching together small data to complete the entire image. During the complete-arch impression procedure, a deformation of the impression body can occur and affect the fit of the restoration or appliance. In order to measure these distortions, a master specimen was designed and produced with a metal 3D printer. Designed reference geometries allow setting independent coordinate systems for each impression and measure x, y, and z displacements of the cylinder top circle center where the distortion of the impression can be evaluated. In order to evaluate the reliability of this method, the coordinate values of the cylinder are calculated and compared between the original computer-aided design (CAD) data and the reference data acquired with the industrial scanner. The coordinate differences between the two groups were mostly less than 50 &#181;m, but the deviations were high due to the tolerance of 3D printing in the z coordinates of the obliquely designed cylinder on the molar. However, since the printed model sets a new standard, it does not affect the results of the test evaluation. The reproducibility of the reference scanner is 11.0 &#177; 1.8 &#181;m. This test method can be used to identify and improve upon the intrinsic problems of an intraoral scanner or to establish a scanning strategy by measuring the degree of distortion at each part of the complete-arch digital impression.

Here, we present a protocol to measure the degree of distortion at each part of the compete-arch digital impression acquired from an intraoral scanner with 3D-printed metal phantom with standard geometries.

Digital workflows have actively been used to produce dental restorations or oral appliances since dentists started to make digital impressions by ...

Engineering

Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base for dental restorations. The current limitation of many reference scanners is the lack of accuracy scanning large objects like full dental arches, or the limited possibility to assess detailed tooth surfaces. A new reference scanner, based on focus variation scanning technique, was evaluated with regards to highest local and general accuracy. A specific scanning protocol was tested to scan original tooth surface from dental impressions. Also, different model materials were verified. The results showed a high scanning accuracy of the reference scanner with a mean deviation of 5.3 &#177; 1.1 &#181;m for trueness and 1.6 &#177; 0.6 &#181;m for precision in case of full arch scans. Current dental impression methods showed much higher deviations (trueness: 20.4 &#177; 2.2 &#181;m, precision: 12.5 &#177; 2.5 &#181;m) than the internal scanning accuracy of the reference scanner. Smaller objects like single tooth surface can be scanned with an even higher accuracy, enabling the system to assess erosive and abrasive tooth surface loss. The reference scanner can be used to measure differences for a lot of dental research fields. The different magnification levels combined with a high local and general accuracy can be used to assess changes of single teeth or restorations up to full arch changes.

Accuracy is a major demand in dental medicine. To verify accuracy, reference scanners are needed. This article presents a new reference scanner with an adjusted scanning method to acquire a broad variety of dental morphologies with high trueness and precision.

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base ...

Biplanar Videoradiography to Study the Wrist and Distal Radioulnar Joints

Accurate measurement of skeletal kinematics in vivo is essential for understanding normal joint function, the influence of pathology, disease progression, and the effects of treatments. Measurement systems that use skin surface markers to infer skeletal motion have provided important insight into normal and pathological kinematics, however, accurate arthrokinematics cannot be attained using these systems, especially during dynamic activities. In the past two decades, biplanar videoradiography (BVR) systems have enabled many researchers to directly study the skeletal kinematics of the joints during activities of daily living. To implement BVR systems for the distal upper extremity, videoradiographs of the distal radius and the hand are acquired from two calibrated X-ray sources while a subject performs a designated task. Three-dimensional (3D) rigid-body positions are computed from the videoradiographs via a best-fit registrations of 3D model projections onto&#160;to each BVR view. The 3D models are density-based image volumes of the specific bone derived from independently acquired computed-tomography data. Utilizing graphics processor units and high-performance computing systems, this model-based tracking approach is shown to be fast and accurate in evaluating the wrist and distal radioulnar joint biomechanics. In this study, we first summarized the previous studies that have established the submillimeter and subdegree agreement of BVR with an in vitro&#160;optical motion capture system in evaluating the wrist and distal radioulnar joint kinematics. Furthermore, we used BVR to compute the center of rotation behavior of the wrist joint, to evaluate the articulation pattern of the components of the implant upon one another, and to assess the dynamic change of ulnar variance during pronosupination of the forearm. In the future, carpal bones may be captured in greater detail with the addition of flat panel X-ray detectors, more X-ray sources (i.e., multiplanar videoradiography), or advanced computer vision algorithms.

Biplanar videoradiography (BVR) is an advanced imaging technique for understanding the three-dimensional movement of skeletal bones and implants. Combining density-based image volumes and videoradiographs of the distal upper extremity, BVR is used to study the in vivo motion of the wrist and distal radioulnar joint, as well as joint arthroplasties.

Accurate measurement of skeletal kinematics in vivo is essential for understanding normal joint function, the influence of pathology, disease progression, ...

Bioengineering

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Biplane videoradiography can quantify shoulder kinematics with a high degree of accuracy. The protocol described herein was specifically designed to track the scapula, humerus, and the ribs during planar humeral elevation, and outlines the procedures for data collection, processing, and analysis. Unique considerations for data collection are also described.

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, ...

Digital Hybrid Model Preparation for Virtual Planning of Reconstructive Dentoalveolar Surgical Procedures

Virtual, hybrid three-dimensional (3D) model acquisition is presented in this article, utilizing the sequence of radiographic image segmentation, spatial registration, and free-form surface modeling. Firstly cone-beam computed tomography datasets were reconstructed with a semi-automatic segmentation method. Alveolar bone and teeth are separated into different segments, allowing 3D morphology, and localization of periodontal intrabony defects to be assessed. The severity, extent, and morphology of acute and chronic alveolar ridge defects are validated concerning adjacent teeth. On virtual complex tissue models, positions of dental implants can be planned in 3D. Utilizing spatial registration of IOS and CBCT data and subsequent free-form surface modeling, realistic 3D hybrid models can be acquired, visualizing alveolar bone, teeth, and soft tissues. With the superimposition of IOS and CBCT soft tissue, thickness above the edentulous ridge can be assessed about the underlying bone dimensions; therefore, flap design and surgical flap management can be determined, and occasional complications may be avoided.

A workflow for creating three-dimensional (3D) virtual hybrid models has been designed based on cone-beam computed tomography dataset and intraoral optical scans utilizing radiographic image segmentation methods and free-form surface modeling. Digital models are used for the virtual planning of reconstructive dentoalveolar surgical procedures.

Virtual, hybrid three-dimensional (3D) model acquisition is presented in this article, utilizing the sequence of radiographic image segmentation, spatial ...

Precision of In Vivo Quantitative Tooth Wear Measurement Using Intra-Oral Scans

Quantitative wear measurement is of increasing interest for measuring tooth wear progression. However, most research on quantitative wear measurement has focused on simulated wear or scanned gypsum casts. A 3D Wear Analysis (3DWA) protocol has been developed that analyzes tooth wear in vivo through intra-oral scanners available to dental clinicians. This study investigated the precision of the 3DWA protocol for measuring wear through maximum height loss (mm) and volume change (mm3). Observational prospective wear data from 55 patients were analyzed after 0-1-, 0-3-, and 0-5-year intervals to determine rates of wear, and convenience samples were chosen to test the protocol&#39;s precision on dentitions scanned twice in one sitting and its intra- and inter-rater precision on scans with 0-3- and 0-5-year intervals. Scans were made using intra-oral scanners (IOS) and superimposed using 3D measurement software. T-tests were performed to determine the structural and random error, and trimmed ranges were calculated to interpret the error. For protocol precision, the mean difference was 0.015 mm (-0.002; 0.032, p = 0.076) for height and -0.111 mm3 (-0.250; 0.023, p = 0.101) for volume. The duplicate measurement error was 0.062 mm for height and 0.268 mm3 for volume. The height measurements were precise enough to measure wear after intervals of 0-3 or 0-5 years; however, volume measurements were susceptible to procedural error and operator sensitivity. The 3DWA protocol is precise enough to adequately measure tooth height loss after intervals of a minimum of 3 years or in patients with severe wear progression, but it is not suited to measuring volumetric changes.

Precision of In Vivo Quantitative Tooth Wear Measurement Using Intra-Oral Scans

Quantitative wear measurement is a method of increasing importance in measuring tooth wear progression. We here describe a protocol, its precision, and its intra/inter-rater precision for the acquisition and superimposition of repeated in vivo scanned dentitions in patients with moderate to severe wear, reporting on both height and volume measurements.

Quantitative wear measurement is of increasing interest for measuring tooth wear progression. However, most research on quantitative wear measurement has ...

Dynamic Navigation in Endodontics: Guided Access Cavity Preparation by Means of a Miniaturized Navigation System

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common sequelae of dental trauma but can also occur with stimuli such as caries, bruxism, or after placing a restoration. In order to access the root canal as minimally invasive as possible in case of a necessary root canal treatment, dynamic navigation has recently been introduced in endodontics in addition to static navigation. The use of a dynamic navigation system (DNS) requires pre-operative cone-beam computed tomography (CBCT) imaging and a digital surface scan. If necessary, reference markers must be placed on the teeth before the CBCT scan; with some systems, these can also be planned and created digitally afterward. By means of a stereo camera connected to the planning software, the drill can now be coordinated with the help of reference markers and virtual planning. As a result, the position of the drill can be displayed on the monitor in real-time during preparation in different planes. In addition, the spatial displacement, the angular deviation, and the depth position are also displayed separately. The few commercially available DNS mostly consist of relatively large camera-marker-systems. Here, the DNS contains miniaturized components: a low-weight camera (97 g) mounted on the micromotor of the electric handpiece utilizing a manufacturer-specific connecting mechanism and a small marker (10 mm x 15 mm), which can be easily attached to an individually manufactured intraoral tray. For research purposes, a post-operative CBCT scan can be matched with the pre-operative one, and the volume of tooth structure removed can be calculated by the software. This work aims to present the technique of guided access cavity preparation by means of a miniaturized navigation system from imaging to clinical implementation.

Dynamic navigation systems (DNS) provide real-time visualization and guidance to the operator during endodontic access cavities preparation. The planning of the procedure requires three-dimensional imaging utilizing cone beam computed tomography and surface scans. After the export of the planning data to the DNS, access cavities can be prepared with minimal invasion.

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common ...

Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, pulpitis or apical periodontitis may develop in the long term. Root canal treatment of teeth with severe PCO and pulpal or periapical pathosis is challenging for general practitioners and even for well-equipped endodontic specialists. To ensure detection of the calcified root canal and avoid excessive loss of tooth structure or root perforation, static navigation using templates ("Guided Endodontics") was introduced a few years ago. The general workflow includes three-dimensional imaging using cone-beam computed tomography (CBCT), a digital surface scan, and superimposition of both in a planning software. This is followed by virtual planning of the access cavity and the design of a template that will guide the drill to the desired target point. To do this, a true-to-scale virtual image of the drill must be placed in a way that the tip of the drill reaches the orifice of the calcified root canal. Once the template has been fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) or a 3D printer, guided preparation of the access cavity can be performed clinically. For research purposes, a postoperative CBCT image can be used to quantify the accuracy of the access cavity performed. This work aims to present the technique of static guided endodontics from imaging to clinical implementation.

Guided endodontics describes a template-aided approach for access cavity preparation. The procedure requires cone-beam computed tomography and a surface scan to produce a template. An incorporated sleeve guides the drill to the target point. This allows the preparation of minimally invasive endodontic access cavities in calcified teeth.

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, ...

Semi-Automated Planimetric Quantification of Dental Plaque Using an Intraoral Fluorescence Camera

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area of a tooth that is covered by plaque deposits. Compared to clinical indices, the PPI has a higher discriminatory power, but traditional planimetry is a time-consuming analysis, as the plaque-covered and clean tooth areas have to be determined manually for each image using image-processing software. Here, we present a method for the semi-automated planimetric quantification of dental plaque, which allows for the rapid processing of up to 1,000 images simultaneously. The method exploits the enhanced contrast between disclosed plaque, sound tooth surfaces, and soft tissues in fluorescence images acquired with an intraoral camera. Careful execution of the clinical procedures and accurate image acquisition are crucial steps for the successful semi-automated identification of the plaque-covered areas. The method is suitable for planimetry on sound facial and oral tooth surfaces, on most composite resin restorations, and on teeth with orthodontic brackets, but not on metallic restorations. Compared to traditional PPI recordings, semi-automated planimetry considerably reduces the amount of time spent on the analysis, as well as the subjective human input, thus increasing the reproducibility of planimetric measurements.

This study presents a semi-automated digital image analysis procedure for the planimetric quantification of disclosed dental plaque based on images acquired with an intraoral fluorescence camera. The method allows for the rapid and reliable quantification of dental plaque in the research environment.

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area ...

Evaluation of Maxillary Posterior Tooth Movement Using Digital Superimposition

Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear aligner) therapy, particularly when compared to the use of traditional fixed appliances. This becomes particularly significant in cases involving anteroposterior, vertical, and transverse corrections, where precise comparisons are of paramount importance. To address these inquiries, this study introduces a meticulously devised protocol, placing a primary emphasis on digitally superimposing the movement of maxillary posterior teeth to facilitate accurate analysis. The sample included 25 patients who had completed their first series of Invisalign (clear) aligners. Four maxillary digital models (pre-treatment, post-treatment, ClinCheck-initial, and final models) were digitally superimposed using the palate rugae and dentitions as stable references. A software combination was used for model superimposition and tooth segmentation. Transformation matrices then expressed the differences between the achieved and predicted tooth positions. Thresholds for clinically relevant differences were at &plusmn;0.25 mm for linear displacement and &plusmn;2&#176; for rotation. Differences were assessed using Hotelling's T-squared tests with Bonferroni correction. The mean differences in rotation (2.036&#176; &plusmn; 4.217&#176;) and torque (-2.913&#176; &plusmn; 3.263&#176;) were significant statistically and clinically, with p-values of 0.023 and 0.0003 respectively. De-rotation of premolars and torque control for all posterior teeth were less predictable. All mean differences for the linear measurements were statistically and clinically insignificant, except that the first molars seemed slightly (0.256 mm) more intruded than their predicted position. The clear aligner system appears to meet its prediction for most translational tooth movements and mesial-distal tipping in maxillary posterior teeth for non-extraction cases with mild to moderate malocclusions.

Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment

This manuscript presents a comprehensive protocol to evaluate the three-dimensional (3D) movement of maxillary posterior teeth with clear aligners using digital model superimposition, an invaluable tool in orthodontics and dentofacial orthopedics.

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear ...

A Standardized Approach to Extra-Oral and Intra-Oral Digital Photography

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