Model Analysis2 / orthodontic courses by Indian dental academy
June 16, 2016 | Author: indian dental academy | Category: N/A
Short Description
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry a...
Description
Model Analysis INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
www.indiandentalacademy.com
Dental casts Essential diagnostic aids Provides 3 D view of maxilla and mandible Valuable tool in orthodontic diagnosis and treatment planning.
www.indiandentalacademy.com
Principles of space analysis Space analysis requires a comparison between amount of space available for the alignment of the teeth and the amount of space required to align them properly.
www.indiandentalacademy.com
Two steps in space analysis
1. To calculate the amount of space available 2. To calculate the amount of space required
www.indiandentalacademy.com
Space available can be measured by
By dividing the dental arch into 4 straight line segments By contouring the .026 brass ligature wire to the line of occlusion By using a flexible scale www.indiandentalacademy.com
Space requirement can be measured by
By measuring the sum of M- D width of each tooth from contact point to contact point. www.indiandentalacademy.com
Sum of width of permanent teeth > amount of space available crowding Sum of width of permanent teeth < amount of space available spacing
www.indiandentalacademy.com
Mixed dentition space analysis Permanent dentition space analysis
www.indiandentalacademy.com
Mixed dentition space analysis Three factors are considered mainly sizes of all permanent teeth
arch perimeter Expected changes in the arch perimeter
www.indiandentalacademy.com
There are three basic approaches for space analysis 1. Measurement of teeth on radiographs 2. Estimation from proportionality tables 3. Combination of radiographic and prediction table method
www.indiandentalacademy.com
Measurement of teeth on radiographs
Requires undistorted radiographic image It is necessary to compensate for enlargement of the radiographic image True width of E = True width of unerupted PM Apparent width E Apparent width of unerupted PM
www.indiandentalacademy.com
www.indiandentalacademy.com
1. Measurement of teeth on radiograph Nance analysis 2. Estimation from proportionality tables Moyer’s analysis Tanaka Johnston analysis 3. Combination of radiographic and prediction table Satley and Kerber analysis
www.indiandentalacademy.com
Nance analysis Proposed by (Nance, 1940)
Materials : Sharp dividers A set of periapical radiographs A millimeter rule A piece of .026 inch brass ligature wire A ruled 3 x 5 inch card for recording measurements Set of study models
www.indiandentalacademy.com
Method of determine arch length Amount of space required width of the erupted four mandibular permanent incisors are measured. width of unerupted mandibular canines, first and second premolars on the radiographs are measured.
www.indiandentalacademy.com
Amount of space available A piece of .026 inch brass ligature wire is placed on the lower cast extending from the mesial surface of the first permanent molar on one side of arch to the mesial surface of the first permanent molar on the opposite side. wire should pass over the buccal cusp of the posterior teeth and the incisal edges of anterior teeth. 3.4 mm is subtracted. Two measurements are compared . www.indiandentalacademy.com
Estimation from proportionality tables
Moyer’s analysis Tanaka and Johnston
www.indiandentalacademy.com
Moyer’s analysis Moyers (1969)
The mesiodistal width of the lower incisors is used to predict the size of both the lower and upper unerupted canines and premolars. Why mandibular incisors are chosen?
www.indiandentalacademy.com
Procedure: Measure the sum of mesiodistal width of lower mandibular incisors. Measure the space left behind for 345 on either side. By using Moyer’s probability chart find out the M-D width of upper and lower 345. Compare the space available and space required in all the four quadrants.
www.indiandentalacademy.com
Moyers prediction values
www.indiandentalacademy.com
Advantages: It has minimal error and the range of possible error is precisely known. It can be done with equal reliability by beginner and the expert. It is not time consuming. Does not require special instruments. Can be used for both the arches.
www.indiandentalacademy.com
Tanaka Johnston method: They developed another way to use the width of lower incisors to predict the size of unerupted canines and premolars.
www.indiandentalacademy.com
Combination of radiographic and prediction table Staley and Kerber method This method is used only for mandibular arch Requires periapical radiograph. It is quite accurate method
www.indiandentalacademy.com
All three methods are based on data from white school children of northern European descent.
If patient fits this population group ,the Staley Kerber will give the best result followed by Tanaka Johnston and Moyer’s.
www.indiandentalacademy.com
Mixed dentition mandibular arch length analysis: a step by step approach using the revised Hixon – Oldfather prediction method: Samir Bishara,Robert Staley(1986) Revised prediction equation used the same predictor variables used by Hixon and Oldfather
www.indiandentalacademy.com
Objective :
To obtain the most accurate result for a particular patient by reducing to a minimum of errors involved in measurement and judgment.
www.indiandentalacademy.com
Mandibular tooth size-arch length analysis Step by step approach 1. From the models M-D width of lower central incisor M-D width of lower lateral incisor 2. From the periapical X-rays M-D width of 1PM M-D width of 2PM
www.indiandentalacademy.com
Measurement of posterior and anterior arch length
www.indiandentalacademy.com
3. From Hixon –Oldfather conversion table
www.indiandentalacademy.com
Other parameters need to be considered in the space analysis
www.indiandentalacademy.com
Permanent dentition analysis Digital model analysis
www.indiandentalacademy.com
Permanent dentition analysis: Pont’s Analysis Bolton’s Analysis Ashley Howe’s Analysis Peck and Peck analysis Korkhaus Analysis Little’s irregularity index Carey’s Analysis
www.indiandentalacademy.com
Pont’s analysis Introduced this analysis in (1909)
Measurement of M-D of 4 maxillary incisors determines the ideal arch width in PM and molar area before the eruption of canines.
www.indiandentalacademy.com
Pont’s analysis helps in determining
Dental arch is narrow or normal Need for lateral arch expansion How much expansion is possible at PM and molar area.
www.indiandentalacademy.com
Determination of sum of incisors (S.I.) Determination of measured PM value (M.P.V.) Determination of measured molar value (M.M.V.) Determination of calculated PM value (C.P.V.) S.I. x 100 80 Determination of calculated molar value (C.M.V.) S.I. x 100 64
www.indiandentalacademy.com
If measured value < calculated value
need for expansion
www.indiandentalacademy.com
Did not indicate the sample size Relationships between the form of the skulls and form of dental arch Did not include an assessment of mandibular arch Reliability of index should be tested in other populations.
www.indiandentalacademy.com
Some studies which critically evaluated use of Pont's index Low correlation coefficients between the sum of M-D width of incisors and the arch width in the PM & M region
Smyth & Young(1932) Greve K(1933) Wroms et al (1969) Joondeph and co-workers (1970) Moyers (1988) Lew K (1991) www.indiandentalacademy.com
Dalidjan, Sampson and Townsend (1995) Individual variability was noted Nimkarn et al (1995) Overestimated the desired arch width by an average of 2.5mm to 4.7mm
www.indiandentalacademy.com
Comparison with present study(Indian population) Significant differences b/w male and female for anterior arch width, posterior arch width and sum of incisors. Female values were more variable than male values. Statistical comparison was not possible. Individual variation is large. Moderate correlation coefficients were observed
www.indiandentalacademy.com
Comparison with present study (Tibetans population)
The mean value for the PM index was 79.56% Molar width index was 61% Tibetans have slightly larger inter-molar width as compared with Pont's sample.
www.indiandentalacademy.com
Bolton’s analysis: Introduced by Bolton (1958) There is a ratio exists between M-D width of maxillary and mandibular teeth. Sample: Evaluated 55 cases with excellent occlusion ;44 had been treated orthodontically without extraction and 11 were untreated.
www.indiandentalacademy.com
Materials: Three inch needle pointed dividers Finely calibrated millimeter ruler
Methods : Following measurements were made on each set of cast 1. Sum of mandibular 12 2. Sum of maxillary 12 3. Sum of mandibular 6 4. Sum of maxillary 6
www.indiandentalacademy.com
www.indiandentalacademy.com
The following ratio’s were established by Bolton: Overall ratio: Percentage relationship of mandibular arch length to maxillary arch length. Overall ratio = Sum of mandibular 12 x100 Sum of maxillary 12 Overall ratio was given as 91.3% and standard deviation 1.91
www.indiandentalacademy.com
Anterior ratio Percentage relationship of M-D width of mandibular anteriors to maxillary anteriors. Anterior ratio = Sum of mandibular 6 x100 Sum of maxillary 6 Anterior ratio was given as 77.2% and standard deviation 1.65
www.indiandentalacademy.com
If ratio exceeds the normal ratio, it indicates the discrepancy in the mandibular tooth material. If value is less, then the discrepancy in maxillary tooth material.
www.indiandentalacademy.com
Drawbacks of Bolton’s analysis
Bolton(1958, 1962) Results tabulated were derived from the use of mean figures. So one must consider each patient as an individual. Larry White(1982) Coefficient of correlation b/w the anterior and overall ratios was very low.
www.indiandentalacademy.com
Epker and fish (1986) Geometry of arch form was not considered. Labio-lingual thickness of teeth is not taken into account. Axial inclination of teeth was not considered. Moyer’s (1988) Sexual dimorphism in maxillary cuspids was not considered.
www.indiandentalacademy.com
Comparison with present study Significant differences were observed for mean value of TTM and anterior tooth material. For the overall ratio significant differences were observed for female. Showed very minimal magnitude of sexual dimorphism.
www.indiandentalacademy.com
Ashley Howe’s Analysis: In 1947 his first article was published in AJO and oral surgery which dealt with adequacy of apical base. In 1954 published another article:considered the relationship of TTM to supporting bone. He measured 14 normal dentition and 200 subsequent cases.
www.indiandentalacademy.com
Methods • • •
Determination of total tooth material(T.T.M.) Determination of premolar diameter (P.M.D.) Determination of premolar basal arch width (P.M.B.A.W.)
www.indiandentalacademy.com
www.indiandentalacademy.com
Ratios were derived separately for maxilla and mandible
PM distance ratio= PM distance x 100 TTM Basal arch width ratio= Basal arch width x 100 TTM Basal arch length ratio= Basal arch length x 100 TTM
www.indiandentalacademy.com
Inference The P.M.B.A.W.and P.M.D. are compared. If P.M.B.A.W is < P.M.D. arch expansion is possible. If P.M.B.A.W is > P.M.D arch expansion is not possible. P.M.B.A.W Ratio: The ratio between the apical base width at the premolar region and the total tooth material is called the P.M.B.A.W percentage.
www.indiandentalacademy.com
P.M.B.A.W % = P.M.B.A.W. x 100 T.T.M. IF P.M.B.A.W.% is 37% or less. If P.M.B.A.W.% is 44% or more If P.M.B.A.W.% is 37-44%
www.indiandentalacademy.com
Evaluation of Howe’s index. Martinek(1957) disagreed because Howe's analysis was derived from limited no. of normal occlusions based only on clinical cases. Stifter(1958) Howe's theory stating that ‘canine fossa cannot be exceeded by bicuspid arch width’ is not valid. Moyers(1988) more logical and superior to Pont’s index.
www.indiandentalacademy.com
Comparison with present study Only an approximate comparison could be made Significant differences were observed both in maxilla and mandible for TTM and BAW for males. Significant differences existed in maxilla only for bicuspid ratio. Significant differences were observed both in maxilla and mandible for TTM, bicuspid distance ,bicuspid ratio,basal arch width and BAL. Some cases bicuspid width exceeded the basal arch width. www.indiandentalacademy.com
Comparison with present study(Tibetan population) PMD,PMBAW and PMBAW/TTM values are higher than Howe’s in both in mandibular and maxillary arch.
www.indiandentalacademy.com
Peck and Peck Analysis This analysis was proposed by Harvey Peck and Sheldon Peck AJO-DO (1972)
Purpose of this article is to present the scientific basis and the clinical application of a new method for detecting and evaluating tooth shape deviations of the mandibular incisors.
www.indiandentalacademy.com
Materials and methods Two groups of young female First group- Group with perfect mandibular incisor alignment Second group – Control population group
www.indiandentalacademy.com
First group 45 subjects Complete mandibular dentition No orthodontic treatment received A proximal contact present among the mandibular incisor. The absence of overlapping in the mandibular incisors Minimal rotational deviation from the ideal . Second group consisted of 70 subjects of comparable age
www.indiandentalacademy.com
In both the groups the maximal M-D and the maximal F-L dimensions were measured directly in patients mouth by Helios Dial Caliper.
Index = MD crown diameter in mm x 100 FL crown diameter in mm Desirable MD/FL index values are Mandibular central incisor:88-92 Mandibular lateral incisor: 90-95
www.indiandentalacademy.com
Higher the MD/FL index –Greater the tooth shape deviation and greater the likelihood of associate crowding.
www.indiandentalacademy.com
Various studies which supports this analysis are:
Boese (1980) Guide for interproximal tooth reduction Barrer (1975) Boese (1980) Shape of these teeth is important in protecting the integrity of this region after orthodontic therapy.
www.indiandentalacademy.com
Various criticisms on peck and peck index Various studies have reported that there is lack of relationship b/w the shape ratios and lower incisor crowding. Narrow MD widths of mandibular incisors did not insure long term stability in orthodontically treated cases.
Kuftinec (1975) Keene and Engle (1979) Gilmore and Little (1984) Puneky, Sadowsky and Begole (1984) www.indiandentalacademy.com
Comparison with present study (Indian population)
Significant difference were observed for the tooth shape ratios for well aligned CI & LI b/w two sexes Significant difference was found for the M-D width b/w two sexes.
www.indiandentalacademy.com
Comparison with present study (Tibetans population)
Range observed in the present study was very wide : 80-109%
www.indiandentalacademy.com
The irregularity index:A quantitative score of mandibular anterior alignment Robert M Little AJO 1975 Measuring the linear displacement of the anatomic contact point, the sum of these five displacements represents the relative degree of anterior irregularity.
www.indiandentalacademy.com
Material and methods Dial caliper calibrated to at least tenth of a mm .
Mandibular casts Measurements are obtained directly from the mandibular cast. Caliper is held parallel to the occlusal plane. Each of the five measurements represents a horizontal linear distance between the anatomic point of the adjacent teeth.
www.indiandentalacademy.com
www.indiandentalacademy.com
Each cast was subjectively ranked on a scale ranging from 0-10 0 perfect alignment 1-3 minimal irregularity 4-6 moderate irregularity 7-9 severe irregularity 10 Very severe irregularity
www.indiandentalacademy.com
Korkhaus analysis He proposed two index 1. Anterior arch length index 2. Palatal height index 1. Anterior arch length index Introduced in (1938)
www.indiandentalacademy.com
Material and method Masel dental dial caliper Korkhaus 3 D orthodontic divider Metallic scale Finely pointed lead pencil Dental casts www.indiandentalacademy.com
Formula for calculating the standard value of upper anterior arch length Sum of upper incisors x 100 160
www.indiandentalacademy.com
Comparison with present study (Indian population) No statistically significant difference were observed for the mean values of ant. arch length and arch length index. SI shows significant differences b/w male and female Statistical comparison was not done because the sample size was not specified Large differences were noticed b/w the observed and predicted arch lengths
www.indiandentalacademy.com
Palatal height index
This index was introduced in (1939). Purpose of this index was to evaluate the palatal shape. Posterior arch width = mesial pits on occlusal surface of upper first molar Palatal height = perpendicular distance from the connecting line between the reference points for posterior arch width to the surface of the palate www.indiandentalacademy.com
www.indiandentalacademy.com
Average value for palatal index is 42% and is derived from the formula Palatal height x100 Posterior arch width Increased value shows that the palatal vault is high relative to transverse arch development. Decreased value shows that palatal vault is shallow
www.indiandentalacademy.com
Comparison with present study (Indian population) Significant differences were observed b/w the two sexes for all the variables related to this index. Posterior arch width, palatal depth & palatal depth index. Weak correlation was observed b/w palatal depth and posterior arch width.
www.indiandentalacademy.com
Comparison with present study (Tibetans population) Tibetans have shallow palate as shown korkhaus palatal height index.
www.indiandentalacademy.com
Carey’s analysis
Helps in determining the extent of discrepancy
Performed in lower cast Same analysis on upper cast is called arch perimeter analysis
www.indiandentalacademy.com
Determination of arch length
Arch length anterior to first permanent molar is measured by using a soft brass wire. The wire is placed touching the mesial surface of the first permanent molar and is passed over the buccal cusps of premolar and along the anterior and is continued on the opposite side.
www.indiandentalacademy.com
Determination of tooth material M-D width of teeth anterior to first molars is measured and summed Inference If discrepancy is 0-2.5 mm minimal tooth material excess,proximal reduction can be carried out 2.5 – 5 mm need to extract second PM > 5 mm need to extract the first PM
www.indiandentalacademy.com
Digital study model Dental cast: Advantages Production is easy,routine and predictable Relatively inexpensive to produce Easy to examine and measure Can be mounted articulated in variety of ways to stimulate occlusal relationships. True 3D medium that accurately represents normal malocclusions. www.indiandentalacademy.com
Disadvantages : Storage is a major problem Easily lost or damaged Bulky to transfer
www.indiandentalacademy.com
Various methods have been employed in 3D assessment and recording of dental study models These includes: Holography Moire topography Various types of lasers
www.indiandentalacademy.com
Holography Introduced in 1948 and involved microscopy by reconstructed wavefronts. Materials Holography camera Disadvantages Expensive Difficult to produce Cannot be manipulated as a set of study models can Poor quality of recording www.indiandentalacademy.com
Moire Topography Contour mapping technique designed to produce successive contour lines directly on an object. Disadvantage Resolution is poor especially for dental morphology
www.indiandentalacademy.com
Two software are commercially available for digital study models Ortho Cad by Cadent Inc, Fairview, N.J., U.SA. E- models by Geodigm Corporation, Minnesota U.S.A.
www.indiandentalacademy.com
Orthocad Steps involved in preparing Orthocad DSM
Step 1: alginate impressions and wax bite are taken. Step 2: mailed to the computer center Step 3: digital models are sent from company to the user through the internet. Step 4: digital models can be utilized with Ortho CAD 3D software.
www.indiandentalacademy.com
Three components are mainly required FTP software Designated folder on the hard disc An electronic browser Program runs on any MS windows File size of each model is about 3 MB Can be stored on any hard disc or CD (CD of 650 MB allows storage of 200 models)
www.indiandentalacademy.com
www.indiandentalacademy.com
www.indiandentalacademy.com
Advantages of ESM are: Can be easily recalled at the touch of button at each patient visit. Can be sent any where around the world Valuable tool in tele conferencing with virtual display Tooth material analysis can be calculated rapidly The model can be electronically sectioned sagitally or transversely. Five simultaneous view of model in the same window.
www.indiandentalacademy.com
Limitations Inability to articulate the models in terminal hinge position Yet to be approved for American Board Certification
www.indiandentalacademy.com
E- models This software is very similar to Ortho Cad excepting that the features are perhaps a shade lesser.
www.indiandentalacademy.com
Frontal asymmetry analysis Cephalometrics for orthognathic surgery Soft tissue cephalometric analysis for orthognathic surgery www.indiandentalacademy.com
Cephalometry Scientific measurement of the dimensions of the head. Roengenographic Cephalometry (Krogman & Sassouni ) The measurement of the head from the shadows of bony and soft tissue landmarks on the radiographic image became known as Roentgenographic Cephalometry.
www.indiandentalacademy.com
Purpose of Cephalometry
In morphological analysis In growth analysis In treatment analysis
www.indiandentalacademy.com
History 16 century artists Albretcht Durer and Leonardo da Vinci had sketched series of human faces with straight lines joining homologous anatomic stuctures.
www.indiandentalacademy.com
www.indiandentalacademy.com
Backward hanging Forward hanging or or Retroclined facial contour Proclined facial contour (De Coster & Moorees) www.indiandentalacademy.com
Teleroentgenographic technique Pacini (1922) The following authors Mac Gowen (1923) Simpson (1923) Compte (1927) Riesner (1929) & others
www.indiandentalacademy.com
In (1931) Broadbent in USA & Hofrath in Germany simultaneously & independently developed standardized methods for production of cephalometric radiographs using special holder known as cephalostat. Cephalostat two types: Broadbent-Bolton method Higley method www.indiandentalacademy.com
Anatomic structures in the cephalogram
The major bony structures are Sphenoid bone Zygomatic bone Maxillae Mandible
www.indiandentalacademy.com
Sphenoid bone
www.indiandentalacademy.com
Zygomatic bone
www.indiandentalacademy.com
Maxillary bone
www.indiandentalacademy.com
Mandible
www.indiandentalacademy.com
In lateral cephalogram
Unilateral landmarks Bilateral landmarks
www.indiandentalacademy.com
In posteroanterior projection
Midline structures Bilateral structures
www.indiandentalacademy.com
Posteroanterior (frontal) Cephalometry Importance Dentoalveolar and facial asymmetry Dental and skeletal cross bites Functional mandibular displacements Qualitative and quantitative evaluation of dentofacial region
www.indiandentalacademy.com
Cephalometric set-up
Head holder or Cephalostat X-ray source Cassette holder containing the film
www.indiandentalacademy.com
Natural head position Natural head position is a standardized orientation of the head,which is readily assumed by focusing on a distant eye level. (Moorrees, 1985)
www.indiandentalacademy.com
Fixed head position
www.indiandentalacademy.com
Other techniques of head positioning Chierici(1981) , patients head should be positioned with the tip of the nose and forehead lightly touching the cassette holder.
www.indiandentalacademy.com
Other techniques of head positioning Faber (1985) PA cephalogram should be taken with the mouth of the patient is slightly opened. (significant mandibular displacement cases)
www.indiandentalacademy.com
Structures that should be included in the tracing of PA cephalogram
www.indiandentalacademy.com
Purpose of PA Cephalometry Gross inspection Description and comparison Diagnosis Treatment planning Growth assessment and evaluation of treatment results
www.indiandentalacademy.com
A Frontal Asymmetry Analysis Grummons analysis Ricketts analysis Grayson analysis Hewitt analysis Chierici method
www.indiandentalacademy.com
Grummons Analysis Proposed by Duane C Grummons (1987) Martin A Kappeyene Van De Coppello Comparative and quantitative posteroanterior Cephalometric analysis not normative. Two forms Comprehensive frontal analysis Summary frontal analysis
www.indiandentalacademy.com
Landmarks and abbreviations
www.indiandentalacademy.com
Different components of Grummons Analysis
Horizontal planes Mandibular morphology Volumetric comparison Maxillomandibular comparison of asymmetry Linear asymmetry assessment Maxillomandibular relation Frontal vertical proportions www.indiandentalacademy.com
Horizontal planes Four horizontal planes are constructed: Connecting the medial aspects of the zygomaticofrontal suture (Z) Connecting the centres of the zygomatic arches Connecting the medial aspects of the jugal process (J) Parallel to the Z plane through menton
www.indiandentalacademy.com
Horizontal planes
www.indiandentalacademy.com
Mid sagittal reference line (MSR)
www.indiandentalacademy.com
Mandibular morphology
www.indiandentalacademy.com
Volumetric comparison
www.indiandentalacademy.com
Maxillomandibular comparison of asymmetry
www.indiandentalacademy.com
Linear asymmetry assessment
www.indiandentalacademy.com
Maxillomandibular relation
www.indiandentalacademy.com
Frontal vertical proportions • Upper facial ratio- CgANS/Cg-Me • Lower facial ratio- ANSMe/Cg-Me • Maxillary ratio- ANSA1/ANS-Me • Total maxillary ratioANS –A1/Cg-Me • Total mandibular ratio- B1 –Me/Cg-Me • Maxillo-mandibular ratioANS-A1/B1-Me www.indiandentalacademy.com
Comprehensive frontal analysis
www.indiandentalacademy.com
Summary frontal analysis Includes: Construction of horizontal planes Mandibular morphology analysis Maxillomandibular comparison of facial asymmetry
www.indiandentalacademy.com
Summary frontal analysis
www.indiandentalacademy.com
Grayson Analysis (Barry H Grayson et al 1983, AJO-DO) Analyzing craniofacial asymmetry with the use of multiplane posteroanterior cephalometry. Landmarks are identified in different frontal planes at selected depths of the craniofacial complex and subsequent skeletal midlines are constructed.
www.indiandentalacademy.com
Tracing 1 Orbital rims Pyriform aperture Maxillary and mandibular incisors Mid point of the symphysis.
www.indiandentalacademy.com
Midline construct for A plane
www.indiandentalacademy.com
Tracing 2 Greater and the lesser wing of the sphenoid Zygomatic arch(the most lateral cross- section) Maxillary and mandibular first permanent molar The body of the mandible The mental foramina
www.indiandentalacademy.com
Midline construct for the B plane
www.indiandentalacademy.com
Tracing 3 Superior surface of petrous portion of temporal bone Mandibular condyle with outer border of ramus Mastoid process
www.indiandentalacademy.com
Midline construct for C plane
www.indiandentalacademy.com
Superimposition of three tracings
www.indiandentalacademy.com
Key triangles are constructed in each of the horizontal planes and related to the posterior midsagittal plane.
www.indiandentalacademy.com
.
Superimposition of the triangles shows that the greatest amount of deviation from the midline occurs at the level of the mandible (C), decreasing in a cephalic direction, Maxilla,(B) Cranial base(A).
www.indiandentalacademy.com
Rickett’s Analysis (Rickett’s et al, 1972) Following clinical norms are presented : Nasal cavity width Mandibular width Maxillary width Symmetry Intermolar width Intercuspid width Denture symmetry Upper to lower molar relation www.indiandentalacademy.com
Hewitt analysis Hewitt (1975),by dividing the craniofacial complex in dividing triangles. Different regions are: The cranial base The lateral maxillary region The upper maxillary region The middle maxillary region The lower maxillary region The dental region The mandibular region www.indiandentalacademy.com
Triangulations of the face
www.indiandentalacademy.com
Chierici method Chierici, (1983)
www.indiandentalacademy.com
An assessment of the range of variation in bilateral location of various skeletal structures from posteroanterior radiographs of acceptable faces. Dr. Amitabh Kallury, September 1999 Aims and objectives To determine the acceptable range of deviations in facial symmetry. To determine which of the two sagittal plane CgANS and ZZ-ANS is more reliable.
www.indiandentalacademy.com
Sample 30 males and 30 females (18-27 years)
Conclusion 1.Norms are proposed for the acceptable variation in the location of bilateral skeletal structures in the postero anterior radiographs.
www.indiandentalacademy.com
2. Cg- ANS was more reliable than ZZ- ANS as the MSR Anatomic and developmental considerations Smaller mean and standard deviation of the landmarks From a practical point of view
www.indiandentalacademy.com
Cephalometrics for orthognathic surgery Soft tissue cephalometric analysis for orthognathic surgery Soft tissue analysis Model analysis www.indiandentalacademy.com
Cephalometric analysis for orthognathic surgery (COGS) Developed at the University of Connecticut by Burstone et al (1978)
www.indiandentalacademy.com
Landmarks used in cephalometric analysis Sella (S) Nasion (N) Articulare(Ar) Pterygomaxillary fissure (PTM) Subspinale (A) Pogonion (Pg) Supramentale (B) Anterior nasal spine (ANS) www.indiandentalacademy.com
Menton (Me) Gnathion (Gn) Posterior nasal spine (PNS) Mandibular plane (MP) Nasal floor (NF) Gonion (Go)
www.indiandentalacademy.com
Landmarks
www.indiandentalacademy.com
1. Cranial Base Horizontal plane Length of the cranial base : Ar to N To determine the horizontal distance between the posterior aspect of maxilla and mandible:Ar to Ptm
www.indiandentalacademy.com
Cranial Base
www.indiandentalacademy.com
2. Horizontal Skeletal Profile Skeletal facial convexity N-A N-B N-Pg
www.indiandentalacademy.com
Horizontal skeletal profile Skeletal facial convexity N-A N-B N-Pg
www.indiandentalacademy.com
Vertical skeletal and dental discrepancy Vertical skeletal component Anterior component Posterior component
Anterior component Middle third facial height Lower third facial height
www.indiandentalacademy.com
Vertical skeletal dysplasia Posterior maxillary height Mandibular plane angle Vertical dysplasia of the posterior components
www.indiandentalacademy.com
Anterior and posterior skeletal component of the face help in the Diagnosis of maxillary hyperplasia or hypoplasia. Rotation of the maxilla and mandible. Typical surgical correction of these problems includes: Total maxillary advancement or reduction. Posterior maxillary vertical augmentation reduction. Combination of anterior or posterior maxillary vertical augmentation or reduction. Mandibular ramus rotation. Ramus height reduction. www.indiandentalacademy.com
Vertical Dental Dysplasia Two components Anterior component Posterior component Anterior component Anterior maxillary dental height or Total vertical dimension of premaxilla Anterior mandibular dental height or Total vertical dimension of anterior mandible www.indiandentalacademy.com
Vertical skeletal and dental measurements
www.indiandentalacademy.com
Posterior dental measurement Determines the posterior molar eruption or Posterior dental mandibular or maxillary vertical height
www.indiandentalacademy.com
Maxilla and Mandible Maxilla Length of the maxilla (PNS-ANS)
Mandible Length of the mandibular ramus(Ar-Go) Length of the mandibular body(Go-Pg) Relationship between ramal plane and mandibular plane(Ar-Go-Gn) Prominence of chin(B-Pg)
www.indiandentalacademy.com
Maxilla and mandible
www.indiandentalacademy.com
These measurements are helpful in diagnosis of Ramus height Mandibular body length Acute or obtuse gonial angle Assessment of chin prominence
www.indiandentalacademy.com
Dental relationship
Occlusal plane Mandibular plane Nasal floor
www.indiandentalacademy.com
Occlusal plane OP angle Increased OP-HP may be associated with Skeletal open bite Lip incompetence Increased facial height Increased mandibular plane angle Decreased OP-HP may be associated with Deep bite Decreased facial height Lip redundancy www.indiandentalacademy.com
Measurements of AB-OP
www.indiandentalacademy.com
Angulation of mandibular central incisor to MP Angulation of maxillary central incisor to NF
www.indiandentalacademy.com
Soft tissue cephalometric analysis for orthognathic surgery
www.indiandentalacademy.com
Cephalometric landmarks Glabella (G) Columella point (Cm) Subnasale (Sn) Labrale superius (Ls) Stomion superius (Stms) Stomion inferius (Stmi) Labrale inferius (Li)
www.indiandentalacademy.com
Mentolabial sulcus (Si) Soft tissue pogonion (pg’) Soft tissue gnathion (Gn’) Soft tissue menton (Me’) Cervical point (C) Horizontal reference plane(HP)
www.indiandentalacademy.com
Cephalometric landmarks
www.indiandentalacademy.com
The soft tissue analysis Facial form Angle of facial convexity Relationship of the maxilla and mandible Position of Pogonion Lower face neck angle (Sn-Gn’-C) Assessment of lower face vertical ht. to depth. (Sn-Gn’/Gn’-C) The ratio of middle third face ht. to lower third face ht. measured to HP www.indiandentalacademy.com
Measurements of facial form
Angle of facial convexity Lower face – neck angle Lower vertical ht.depth ratio
www.indiandentalacademy.com
Anteroposterior maxillary and mandibular measurements Vertical facial height proportionality
www.indiandentalacademy.com
Lip position Nasolabial angle Antero posterior lip position Mentolabial sulcus Upper and lower lip protrusion Interlabial gap Lower third facial height proportionality
www.indiandentalacademy.com
Lip position
Nasolabial angle A-P max. dysplasia position of upper lip Mentolabial sulcus
www.indiandentalacademy.com
Lip position
Interlabial gap Lower third facial height proportionality Antero posterior lip position
www.indiandentalacademy.com
Soft tissue analysis
www.indiandentalacademy.com
Soft tissue landmarks Glabella (G) Columella point (Cm) Subnasale (Sn) Labrale superius (Ls) Stomion superius (Stms) Stomion inferius (Stmi) Labrale inferius (Li)
www.indiandentalacademy.com
Mentolabial sulcus (Si) Soft tissue pogonion (pg’) Soft tissue gnathion (Gn’) Soft tissue menton (Me’) Cervical point (C) Horizontal reference plane(HP)
www.indiandentalacademy.com
Soft tissue landmarks
www.indiandentalacademy.com
Cephalometric planes of reference
Sella – nasion plane Frankfort horizontal Constructed horizontal plane
www.indiandentalacademy.com
Soft Tissue Evaluation: Frontal View Vertical facial proportions Facial symmetry Maxillary incisor to lip relationship
www.indiandentalacademy.com
Vertical facial proportions The Roman architect Vitruvius had divided the face into three equal parts.
www.indiandentalacademy.com
Facial symmetry Face is divided along the mid-sagittal plane
www.indiandentalacademy.com
Composite photograph to indicate normal facial asymmetry
www.indiandentalacademy.com
Maxillary incisor to lip relation Stomion superius to incisal edge of maxillary incisor
www.indiandentalacademy.com
Soft tissue evaluation : Profile view Middle to lower third facial ratio Upper lip – lower lip height ratio Assessment of the nose Nasomental angle Nasolabial angle Maxillary prognathism Upper lip prominence
www.indiandentalacademy.com
Mandibular prognathism Lower lip prominence Interlabial gap Chin prominence Chin neck contour Angle of facial convexity E-line Merrifield’s Z angle
www.indiandentalacademy.com
Vertical proportions in profile view Middle to lower third facial ratio Upper lip- lower lip height ratio
www.indiandentalacademy.com
Assessment of nose Landmarks used to evaluate the nose are: Glabella The radix The nasal dorsum The tip of the nose The columella Nasolabial angle
www.indiandentalacademy.com
Nasofacial angle
www.indiandentalacademy.com
Inclination of the nasal base
www.indiandentalacademy.com
Nasomental angle
www.indiandentalacademy.com
Nasolabial angle
www.indiandentalacademy.com
Horizontal nasal prominence Schiedeman et al (Glabella-Pronasal) should be approximate one third of the vertical ht. of the nose (glabella –subnasale)
www.indiandentalacademy.com
Mentocervical angle Submental- neck angle
www.indiandentalacademy.com
Maxillary and mandibular prognathism
www.indiandentalacademy.com
Upper lip-Lower lip prominence
www.indiandentalacademy.com
Upper lip- lower lip-Chin prominence
www.indiandentalacademy.com
0 –Degree Meridian
www.indiandentalacademy.com
Angle of facial convexity
www.indiandentalacademy.com
Rickett’s E-Line
www.indiandentalacademy.com
Stiener’s S-line
www.indiandentalacademy.com
Merrifield’s Z angle
www.indiandentalacademy.com
The Holdaway Soft -Tissue Analysis
www.indiandentalacademy.com
Holdaway Soft Tissue Analysis Reed Holdaway
His analysis comprises 11 measurements Facial angle Upper lip curvature Skeletal convexity at point A H-line angle Nose tip to H- line Upper sulcus depth Upper lip thickness
www.indiandentalacademy.com
Upper lip strain Lower lip to H- line Lower sulcus depth Soft tissue - chin thicknes
www.indiandentalacademy.com
Facial angle –upper lip curvature
www.indiandentalacademy.com
Holdaway’s H line Angle
www.indiandentalacademy.com
Nose Tip to H line Upper Sulcus Depth Lower lip to H - line Lower sulcus Depth Soft-tissue chin thickness.
www.indiandentalacademy.com
Upper lip thickness
www.indiandentalacademy.com
Thank you For more details please visit www.indiandentalacademy.com
www.indiandentalacademy.com
View more...
Comments
