1. There are several methods for predicting surgical outcomes of orthognathic surgery, including manual tracings, computer software programs, and video imaging.
2. Studies have found that current prediction methods tend to be inaccurate, especially in predicting soft tissue changes like lip and chin positions. Predictions often differ from actual outcomes by 2mm or more.
3. While prediction images can help communicate treatment plans to patients, they may also unintentionally create unrealistic expectations that are not always achieved. More accurate prediction methods are still needed.
COGS analysis (Cephelometrics for orthognathic surgery) / fixed orthodontics ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
COGS analysis (Cephelometrics for orthognathic surgery) / fixed orthodontics ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This slide gives you a detailed description of History
,Bone screws,Maxillary infra-zygomatic bone crest anatomy,Dimensions of IZC,Indications of IZC,Sites of placing IZC Screws,Mini-screw insertion in IZ crest of maxilla,Biological limitation for placement of IZC for distalization,General guidelines for placing IZC,Post operative care,Failures of IZC
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Pre & post surgical orthodontics /certified fixed orthodontic courses by Indi...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Hybrid appliances are specifically and individually tailored to exploit the natural processes of growth and development. Such an approach represents a departure from the practice of adopting a "named" appliance for the treatment of a class of malocclusion
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This slide gives you a detailed description of History
,Bone screws,Maxillary infra-zygomatic bone crest anatomy,Dimensions of IZC,Indications of IZC,Sites of placing IZC Screws,Mini-screw insertion in IZ crest of maxilla,Biological limitation for placement of IZC for distalization,General guidelines for placing IZC,Post operative care,Failures of IZC
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Pre & post surgical orthodontics /certified fixed orthodontic courses by Indi...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Hybrid appliances are specifically and individually tailored to exploit the natural processes of growth and development. Such an approach represents a departure from the practice of adopting a "named" appliance for the treatment of a class of malocclusion
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Videocephalometry/certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Videocephalometry /certified fixed orthodontic courses by Indian dental aca...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
deep learning applications in medical image analysis brain tumorVenkat Projects
The tremendous success of machine learning algorithms at image recognition tasks in recent years intersects with a time of dramatically increased use of electronic medical records and diagnostic imaging. This review introduces the machine learning algorithms as applied to medical image analysis, focusing on convolutional neural networks, and emphasizing clinical aspects of the _eld. The advantage of machine learning in an era of medical big data is that signi_cant hierarchal relationships within the data can be discovered algorithmically without laborious hand-crafting of features. We cover key research areas and applications of medical image classi_cation, localization, detection, segmentation, and registration. We conclude by discussing research obstacles, emerging trends, and possible future directions.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
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Financial Implications for Integrating Carestream OnSight 3D Extremity System...Carestream
Carestream Health commissioned a working group of surgeons and administrators from four leading orthopedic practices to
evaluate the clinical application and economic impact of the OnSight 3D Extremity System. This paper outlines the results of that working group’s findings, including specific economic models for practices of various sizes and throughputs.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
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Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
1. ACCURACY OF STO PREDICTION
Introduction:
Orthognathic surgery for the correction of facial deformities and severe malocclusions has
been performed more frequently and involves a much wider range of operative procedures than
in the past. The criteria for a successful surgical outcome is not only the correction of skeletal
and dental abnormalities but also an aesthetic improvement as judged by both patients and
practitioners.
Since Tweed (1954)1 first presented his ‘diagnostic triangle’, many orthodontists including
Steiner, Holdaway and Hilgers have developed the concept of using cephalometric tracings to
establish precise treatment objectives. Holdaway (1983)2 in particular, proposed a method of
overlay prediction tracing for a patient requiring orthodontic treatment. His analysis brought
together factors such as growth increments, stability and soft tissue balance to form a
Visualised Treatment Objective (VTO).
It was Wolford (1985)3 who used the VTO for surgical-orthodontic treatment planning and
coined the term Surgical Treatment Objective (STO).
Uses of an STO: (Taylor 1998)4
Plan dental movements.
Assess need for extractions
Plan mechanics.
Plan type of surgery and nature of osteotomies.
A basis for communication
A basis for informed consenting.
A basis for splint construction.
Provides a reasonable prediction of soft tissue changes, that can provide a basis for computer
imaging.
2. In recent studies, Kiyaki found that 53% of female patients and 41% of male patients listed
aesthetics as a major factor in their decision to proceed with orthognathic surgery. Other
studies report that 76% to 89% of patients rate aesthetics as a moderate to major factor in their
decision to pursue treatment. Clearly a treatment prediction technique that provides both
accurate diagnostic information required for treatment planning and a realistic simulation of
the aesthetic outcome is needed to maximize the chances of patient satisfaction.
Methods of surgical outcome prediction:
The objective of treatment simulation is to allow the clinician to visualize and manipulate the
skeletal and dental structures, so to compare different treatment alternatives.
There are five general methods of visualising, planning and predicting surgical-orthodontic
treatment outcomes.
1. The first method has been in use for the past 20 years.
Acetate tracings of skeletal structures are manually repositioned over the original
cephalometric tracing to simulate the proposed surgical movements.ii
The posttreatment soft tissue outcome is established by using acceptable guidelines for the ratio
of soft to hard tissue changes.
The two major weaknesses of this technique is that:
I. Variables in soft tissue thickness, tonicity, individual responses
II. Differences in the surgeon’s manipulation will introduce uncertainties that make soft tissue
prediction more of an ‘art’ form.
III. The ‘line drawing’ produced by this approach is an inadequate means by which to portray the
proposed result to the patient.
2. Manipulation of patient photographs (cut and past) to illustrate treatment goals.iii. Traditionally,
the lateral cephlogram was traced and superimposed onto a profile picture in a ratio of 1:1; this
has been called a "photometric plan". The photograph, with the hard tissue points marked, was
then cut-up to simulate the pre-surgical orthodontic phase of incisor decompensation. The
necessary surgical movements were then undertaken; followed by the soft tissue response to
the hard tissue movements. The end results sometimes looked a bit like a Picasso picture!
3. 3. Computerised diagnostic and planning software that produced a soft tissue profile ‘line
drawing’ as a result of manipulation of digitised structures of lateral cephalometric
radiographs. iv,v Using any of the commercially available programmes, the clinician can
simulate surgical movements on the screen and rapidly compare different treatment options.
Hard copies can then be used as visual aids in treatment planning. This method of prediction
is no more accurate than manual predictions as the computer predictions are based on the same
guidelines and the resultant line drawing is still lacking in providing a lifelike aesthetic
representation.
4. Computerised diagnostic and planning software that integrates video images with the patient’s
lateral cephalograph to aid in planning and predicting surgical orthodontic procedures
(Videocephalometrics). Visualisation of facial changes is enhanced as is patient/clinician
communication; alternative treatment plans can be evaluated with ease, and realistic patient
expectations may be achieved. (Harradine 1985, Sarver 1988, Sinclair 1995).
5. Three-dimensional computer technology for planning and predicting orthognathic surgery.
Moss et al (1988)vi expanded on the early methods of 3-D planning by including laser
scanning to model the soft tissue response to hard tissue movements.
Two significant advantages of video imaging over other prediction techniques are:
4. The image facilitates communication between clinician and patient by establishing visual
treatment goals for orthodontics and surgery. By involving the patient in the decision of
treatment options, acceptance of the treatment outcome should be improved.
Valuable aid in treatment planing decisions by providing a maniputable image for the
orthodontist and surgeons to decide on the best soft tissue outcome. This technique is also
helpful on deciding the necessity of adjunctive soft tissue procedures.
Radiographic Analysis
In order to use a computer programme to plan orthognathic treatment, the radiograph needs to
be digitised prior to analysis. Two methods are described (Travess and Juggins, 2007):
1. Direct computer digitisation of the radiograph:
• The radiograph is placed onto a digitising light box
• Anatomical points are entered into computer using a cursor or electronic pen
2. Indirect computer digitisation of the radiograph:
• Image is captured (scanned image or true digital image) and stored on the computer.
• Image displayed in orthognathic programme and digitised using a cursor.
Studies have shown that the direct and indirect methods of cephalometric analysis are
comparable (Richardson, 1981; Oliver, 1991; Sarver, 1998).
There are advantages to using the indirect method:
• Digital storage of radiographs allows easy access when required
Use of magnification, alteration of brightness and contrast allow more detailed visualisation of
the image
Orthognathic Prediction Software
There are numerous programmes available for the analyses and prediction of orthognathic
treatment:
• OPAL image version 2.2
• Dolphin imaging 10
• Dentofacial Planner 8.05
• Quick Ceph Image
• Computer assisted simulation system for Orthognathic surgery (CASSOS)
5. There have been several studies evaluating the accuracy of digitisation and validity of
computerised prediction of surgical outcome.
Power et al. (2005) compared the accuracy of cephalometric digitisation and orthognathic
prediction of Dolphin Imaging 8 with manual tracing (the "gold standard"). Both methods were
reliable at identifying cephalometric points. Of note, manual tracing was more reliable for
SNA, SNB, SNMx and MxMd. In contrast Dolphin imaging 8 was more reliable for UIMx and
LIMd, although systematic error in the software meant that LAFH% was 4% larger than
manual tracing (this has been corrected in Dolphin Imaging 10).
Loh et al. (2001) analysed the accuracy and reliability of Quick Ceph Image software (version
3). There was good correlation between repeated digitisation for all measurements. The only
variables to show statistically significant differences were ANB, FMA, SN-Mx1 and Wit's but
only the Wit's analysis showed clinically relevant differences between the two measurements.
The authors concluded that clinicians should be cautious when using this system; it may not be
possible to achieve the planned surgical result based upon this system's information.
CASSOS prediction of hard tissue profiles was evaluated in a retrospective analysis by Loh
and Yoe (2002). Results showed good correlation between repeated digitisation for all
measurements. The differences that were statistically significant were in angular measurements
for SNA, U1-Mx, U1-L1, U1-SN.None of the measurements demonstrated a clinically relevant
difference.
More recently CASSOS was evaluated for its validity in planning surgical correction of Class
III deformities (Jones et al., 2007). Two groups were compared, maxillary advancement and
bimaxillary surgery. For the maxillary advancement group there were statistically significant
differences in three horizontal landmarks: superior labial sulcus, labrale superius and the
labiomental fold. In the bimaxillary group only the landmark labrale superius (in the vertical
direction) showed a statistically significant difference. The authors commented that CASSOS
produced useful predictions; however there was wide interindividual variation, mainly for the
lips.
Smith et al. (2004) investigated the ability of prediction imaging software to simulate the actual
outcome of orthognathic surgery. Five programmes were compared - Dentofacial Planner Plus,
Dolphin imaging, Orthoplan, Quick Ceph Image and Vistadent. Ten difficult vertical
discrepancy cases were chosen and "retreated" with the programmes using the actual surgical
changes. Dentofacial Planner Plus was judged the best default simulation. The authors also
noted that programme choice is not only related to simulation ability but also performance,
cost, ease of use, compatibility, image and and for some practitioners the inclusion of a practice
6. management tool.
OPAL software (Orthodontic planning and analysis) was developed by Nigel Harradine and
David Birnie and George Chauvet in 1983. It has undergone numerous revisions since its initial
presentation. Cousley et al. (2003) investigated the accuracy of OPAL in the calculation of the
total treatment hard tissue and dental changes. Prediction of the majority of the variables was
acceptable, however there was large interindividual variation for most measurements;
prediction of Wits, MxP/MdP, LAFH and LPFH were prone to systematic error. There was
also a tendency towards over-prediction of the surgically-induced backward mandibular
rotation. A follow-on study was carried out which assessed the accuracy of OPAL preoperative
prediction in relation to immediate and long term changes in mandibular advancement
(Cousley and Grant, 2004). Overall the wafer had a limited anterior displacement (0.1mm) but
2.1mm of bite-opening measured at the incisor level. There was little difference in actual and
predicted values for LAFH%, SNA, ANB, OJ and OB. The most pronounced inaccuracies were
in L1/MdP. The vertical skeletal measurements (MxP/MdP, LAFH and LPFH) were
significantly under-estimated in both the immediate and long term predictions. In essence the
programme underestimated the amount of backward rotation of the mandible as it was
advanced.
However, it is important to ask ourselves if the use of 2D prediction software is more useful to
clinicians than to patients and whether patients ever look at themselves in profile?
Phillips et al. (2001) investigated the effects of computerized treatment simulation on patient
expectations of orthognathic treatment. One hundred and forty-six patients requiring combined
orthodontic and orthognathic treatment were randomly allocated to two groups: presurgical
consultation with, and without, computerised treatment simulation software. Viewing a
prediction did not have a significant effect on the anticipation of social relations and general
health in the first month after surgery. Psychologically distressed patients, whether or not they
saw a simulation, expected significantly more problems in social interaction and general health
in the first month after surgery. Treatment simulation did affect patients' overall expectations
of problems in the first month after surgery and their concerns about symptom recovery
VIDEO IMAGINGvii
7. Does the prediction image create an unrealistic expectation of the final result?
Does sharing the image with the patient represent an implicit warranty as to the treatment
outcome?
Phillips et al (1995)10 found that the presentation of video images appears to be a valuable
adjunct for conveying treatment options to patients, but warned that caution may be needed to
avoid elevated or unrealistic treatment expectations. Video imaging was found to heighten
patients’ expectations of improvement in self-image following treatment.
Kiyak (1991)5 showed that fewer than 45% of non-imaged patients were satisfied with their
aesthetic result.
However, Sarver et al (1988)9 found that 89% of the patients believed that the image
predictions were realistic and that desired results were achieved.
Furthermore, 83% believed that the imaging process helped them in deciding whether to have
surgery or not,
72% believed the process allowed them to take part in specific treatment decisions.
Fear that the patients expectations may be too high do not appear to be supported.
How accurate is the prediction?
There are few studies investigating the validity of methods predicting the soft tissue outcomes
after orthognathic surgery.
Pospisil (1987)viii evaluated manual acetate tracings and found 60% inaccuracy when compared
to 6-month postoperative radiographs. He stated that soft tissue profiles in 83% of
2-jaw and 40% of single jaw cases were inaccurately predicted. The magnitude and direction
of discrepancy was not reported.
Hing (1989)ix and Sinclair (1995)14 used records of patients who had mandibular advancement
surgery to investigate the accuracy of computerised soft tissue line drawings. Sinclair et al
(1995) also compared the accuracy of line drawings of patients who had mandibular
advancement with those who had both mandibular advancement and advancement genioplasty.
Sample of 56 patients from the office of one of the authors (D. Sarver), who had completed
treatment involving orthodontics and orthognathic surgery to advance the mandible a minimum
of 5mm. 41 had mandibular advancement only and 15 had an additional advancement
8. genioplasty. All patients were over 18 years old, white and selected on the basis of the
availability of presurgical and posttreatment lateral cephalograms and lateral profile
photographs. All records were taken with teeth together in centric occlusion and lips in repose.
By superimposing the computerized hard tissue prediction (using Prediction Planner/Portrait
imaging system) with the actual hard tissue result, it was possible to compare and analyze the
accuracy of the soft tissue outline.
To assess the accuracy of the video image predictions, the actual initial, the actual final and the
predicted final images were displayed simultaneously on the monitor. These three images were
evaluated and scored independently by an oral surgeon and an orthodontist, for the similarity
between the actual final and the predicted final images.
Actual versus predicted line drawings
The mean differences on the posttreatment soft tissue profile was small and statistically
insignificant for measures other than the lower lip. The computer predicted lip was
significantly more retrusive when compared with the E-line and a vertical through subnasale
(SNV-line). The lower lip was also predicted to be thinner than it actually was.
For 11 of the 18 measurements taken, a 2mm of greater discrepancy was found in at least 20%
of the patients. Differences at the chin point were higher than would be expected from mean
changes alone. For the majority of patients the 2mm discrepancy was an underprediction.
Actual versus predicted video images
1. Mandibular advancement only: predicted and actual images agreed most often in the upper lip
area; poorest agreement in the labiomental fold and submental areas.
2. Genioplasty group: agreement most frequent in upper and lower lip areas.
The percentage of acceptable images was higher in submental areas but lower for
labiomental fold and chin.
71% of mandibular group and 53% of genioplasty group had acceptable predictions at the chin.
Results:
more than 20% of patients had 2mm discrepancy at lower lip and chin. Current prediction
algorithms based of ratios of averages do not reflect the variability of responses and the
9. interrelationships of horizontal, vertical and transverse dimensions. To improve accuracy of
computer line drawings, better data is needed for soft tissue changes that accompany vertical
and horizontal skeletal and dental changes.
all video image predictions were considered acceptable for patient education.
in all cases the actual final images were superior in aesthetics to the prediction images.
the greater the mandibular advancement and the greater the vertical change, the poorer the
lower lip prediction.
Hing used the Quick-Ceph diagnostic software programme and he found that the largest
amount of discrepancy between the computer predicted profile outline and the posttreament
radiographic tracing was in the horizontal position of the lower lip and the vertical position of
soft tissue Pogonion.
predicted position of lower lip was more anterior
predicted position of soft tissue pogonion was more superior
Konstiantos et al (1994)x investigated the accuracy of computer predictions of patients who
had LeFort 1 osteotomy, using the Dentofacial Planner imaging system.
nasal tip (pronasale) and nasal base (subnasale) were more posterior on the prediction
position of lower lip was more retrusive on the prediction
Upton et al (1997) evaluated the accuracy of soft tissue profile ‘line drawings’ predicted by
Quick-Ceph in combined maxillary and mandibular orthognathic surgery procedures. In this
study preoperative and posttreament lateral cephalographs of 40 white patients (10 males, 30
females) who had undergone LF1 and BSSO advancement with or without genioplasty were
used. 45 hard and soft tissue landmarks were digitised for each readiograph. Results indicated
variability among several of the landmark positions when comparing prediction tracings with
posttreament radiographs, with more variability in vertical measurements than in horizontal or
angular measurements. This current study revealed more measurements that were statistically
significantly different from posttreatment tracings than did previous validity studies. One
explanation may be that in this study patients had 2-jaw surgery whereas other study samples
had only single jaw procedures. Other reasons include the different soft and hard tissue ratios
used in different software packages and different statistical methods employed. The Quick-
10. Ceph programme uses soft and hard tissue ratios published by Wolford (1985)3 and Epker and
Fish (1986)xi.
amount and direction of soft tissue changes differed between predicted and actual tracings
most differences were in the horizontal and vertical positions of the lower lip
lower lip was predicted to be more inferior, shorter and more protrusive
upper lip was predicted to be shorter
soft tissue pogonion was predicted to be more inferior
Gerbo (1997)xii in a retrospective study of the accuracy of a prediction algorithm from Quick-
Ceph, digitised lateral cephalographs of 35 adult patients. Results showed good correlation
between repeated digitisation of all variables except soft tissue B point and the E-plane.
Comparison of predicted and actual changes showed that all differences were less than 1.8mm
or 3.1 degrees. 10 of the 16 measurments did not differ significantly and were judged to be
within clinically acceptable limits.
Can the surgeon actually produce the suggested outcome?
Donatsky et al (1997)xiii applied a computerised cephalometric, orthognathic surgical
programme (TIOPS) in simulation, treatment planning and postsurgical records, to assess
precision and stability of bimaxillary surgery. This prospective study included 40 consecutive
patients requiring maxillary superior repositioning combined with mandibular advancement or
setback. All were managed with rigid wire fixation. Planned, 5-week postsurgical and 1-year
postsurgical cephalometric positions were compared.
In mandibular advancement group:
anterior maxilla was placed too far superiorly, with an inaccuracy of 0.4mm. Posterior maxilla
and anterior mandible were placed in the planned positions.
Lower posteior part of mandibular ramus was placed too far anteriorly with inaccuracy of
2.0mm. However condyles were in correct positions.
In mandibular setback group:
anterior maxilla was too far superiorly and posteriorly with a vertical and horizontal inaccuracy
of 1.0mm and 0.7mm respectively.
Lower posteior part of mandibular ramus was placed too posteriorly with inaccuracy of 0.9mm.
Again, condyles were in correct positions.
11. Stability:
1-year data showed maxilla had moved 0.3mm posteriorly in the advancement group and
0.8mm superiorly in the setback group. No significant positional changes were observed in the
mandibular ramus.
They concluded that the TIOPS progamme is useful in orthognathic surgical simulation,
planning and prediction, and also in evaluation of surgical precision and stability. The
simulated treatment plan can be transferred to model surgery and then on to surgical
procedures. The results suggest that this technique yields acceptable postoperative precision
and stability.
In a review of the current capabilities and limitations of video imaging, Grubb et al (1996)11
discusses the factors affecting the accuracy of video imaging. He considers the accuracy of the
predictions is dependent on three components:
accuracy of the computerized cephalometric VTO. Researchers have shown a reasonable
accuracy in the A/P plane when compared to manual tracings, and slightly poorer but still
acceptable accuracy in the vertical plane. All the software tested had problems predicting the
position of the lips, especially the morphology of the lower lip.
ability of the program to fit the facial image onto the corresponding soft tissue cephalometric
outline. All programs tested differed; an optimal system is yet to be developed.
image morphing. Sinclair (1995) reports that 70% of video images produced are accurate
enough for clinical use without any additional operator influence in blending or smoothing the
profiles. Less than 50% of images predicting the position and contour of the lower lip showed
acceptable accuracy.
Soft Tissue Profile Changes Associated with Surgical Movement
The recognition of the importance of aesthetic factors in orthognathic treatment is a very
important part of the planning process. Knowledge of the relationship between hard tissue
changes and the effect this has on the overlying soft tissues is essential when planning and
predicting facial changes.
12. Moss et al. (1988) noted that the various type of orthognathic procedures and the anatomical
morphology of the patient must be considered when predicting the outcome of facial surgery.
Mandibular setback procedures
The first studies on the effects of surgery on the soft tissues were associated with mandibular
reduction procedures (Knowles 1965). It was found that for each 1mm of posterior movement
of the mandible, soft tissue pogonion moved posteriorly between 0.9-1mm while the soft tissue
lip moved back 0.6-0.75mm (Shiu-Shiung et al. 1998).
Mandibular advancement:
Veltkamp et al (2002) confirmed that the direction of surgical movement and preoperative soft
tissue thickness have a definitive effect on the post-operative lower lip position. As the
mandible advances the lower lip contour straightens and the vermillion thins. The authors
confirmed that the effect of maxillary surgery in conjunction with anterior mandibular
advancement on the soft tissue contour of the lower lip is similar to an isolated single jaw
procedure.
Mobarak et al. (2001) investigated changes in soft tissue profiles following mandibular
advancement surgery. In a sample of 61 patients with retrognathic mandibles the authors
confirmed that the soft tissue chin and labio-mental fold followed their underlying skeletal
structures in a 1:1 ratio. They did however suggest that more realistic long term projection may
be achieved if ratios incorporating mean relapse values were used rather than relying on a 1:1
relationship.
Mandibular advancement with genioplasty:
Ewing and Ross (1992) carried out a study on 31 patients investigating the soft tissue response
to mandibular advancement and genioplasty. The results showed a consistent 1:1 ratio of soft
tissue to hard tissue movement at pogonion and point B; with accurate predictions in both
antero-posterior directions. When a genioplasty was added to the advancement, however, the
results became much less consistent. The mean ratio was 0.9:1 but had a variation of +/- 2.6mm
which was not sufficiently accurate for predictive purposes. After genioplasty the soft tissue
pogonion moved inferiorly relative to the underlying hard tissue pogonion. The behaviour of
the lip was also variable between the two groups. Advancement thinned the lip by an average
of 1.7mm. Changes in the vertical dimension were also more variable with a range of 4mm
recorded depending on the operator. This variation means that surgeons must assess the soft
tissue reaction pertaining to their technique.
Maxillary procedures at Le Fort I level:
There have been many studies attempting to assess the soft tissue changes that occur with Le
13. Fort I surgical procedures. Initial ratios proposed by Lines and Stenhauser (1974) stated that
there was a 2:3 soft tissue: hard tissue ratio in the maxilla although the number of patients
included in this study was very small.
Costa et al. (1986) investigated 25 cases of Le Fort I maxillary advancement and naso-labial
reconstruction and found a lip to osseous ratio of 0.9:1. This is a higher ratio than in other
studies but may be due to the naso-labial reconstruction process.
Stella et al. (1989) followed 21 maxillary advancement patients for at least 6 months post-
operatively and found no reliable correlations between bony advancement and soft tissue
position. However they did find that tissue changes varied with different lip thicknesses.
Hack et al. (1992) collected cephalometric data from 25 patients who underwent either a Le
Fort l or a bimaxillary procedure. They aimed to establish the long term stability and prediction
of soft tissue changes after Le Fort I surgery and found that the short term soft: hard tissue
correlations were in the range suggested by previous authors.
They concluded that soft tissue settling and maturation may take several years to complete.
Bimaxillary Procedures
Jensen at al. (1992) investigated the response of simultaneous maxillary impaction and
mandibular advancement. They suggested that the soft tissue responses seen were similar to
single jaw procedures, with the exception of changes to the naso-labial angle and the labio-
mental fold. With maxillary advancement and impaction, the upper lip advanced 90% of the
underlying hard tissue change and moved superiorly by 20% of the hard tissue movement. The
naso-labial angle changed about 60% of the rotation of the maxilla.
Shiu-Shiung et al. (1998) aimed to clarify the soft tissue changes that occur with maxillary
advancement and mandibular set back when correcting Class III malocclusions, using the V-Y
closure technique and alar-base cinch suture. In a sample of 17 patients undergoing bimaxillary
osteotomy, superimposition cephalometric analysis was carried out post-operatively. They
found similar results to previous studies in that the mandibular hard tissue to soft tissue ratio
was 1:1 at pogonion and point B. The maxillary ratios correlated less strongly with maxillary
advancement. The ratio of the superior labial sulcus and A point was less than that of the lower
lip and chin, ranging from 0.4:1 to 0.82:1.
This wide variation may be due to the modification of various cephalometric landmarks such
as ANS.
Vertical movements of the mandible showed a strong correlation in the lower lip and chin but
vertical movement of the maxilla showed a weak correlation at the level of the nasal base and
upper lip.
14. Advancement genioplasty
Shaughnessy et al. (2006) aimed to assess the skeletal stability of advancement genioplasty 3
years after surgery and to evaluate the predictability of soft tissue changes in 21 patients
underwent genioplasty advancement only. At 3 years the soft tissue of the chin was found to
follow the bony movement in a ratio of 0.9:1 but great individual variability was observed.
CONCLUSION:
“ In any creative endeavour, orthodontics included, one must have an idea, a mental image of
his objective.” King12
The integration of video imaging into the counseling of patients on aesthetics considerations
of treatment offer several advantages:
a higher level of communication
more precision in this communication
improved visualisation of individual treatment plans, resulting in greater precision in planning
a desired outcome
a template is provided for decision-making among patient, orthodontist and oral surgeon, with
greater participation by the patient
Quantitates surgical movements
allows facial planing and provided quantitative feedback as to what is required to attain a
particular treatment plan.
It is clear that surgical treament prediction methods are a valuable tool in planning and
simulating treatment objectives. From the literature it appears that manual acetate tracings
alone were more inaccurate in predicting treatment outcomes than the more advanced
technology of video imaging. Different degrees of inaccuracy are reported in different studies
assessing the validity of videocephalometrics, mainly due to different soft /hard tissue ratios
used in various software. With continued technological advancements and the development of
more accurate soft /hard tissue ratios, we can look forward to more accurate prediction methods
that facilitate greater success in orthognathic surgery and greater patient satisfaction.
_____________________________________
15.
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