surgical orthodontics diagnosis / orthodontic courses by indian dental academy

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

SURGICAL ORTHODONTICS –

DIAGNOSIS,

ORTHODONTIC MANAGEMENT AND PREPARATION OF SURGICAL

SPLINT

Surgical Orthodontics

Orthognathic Surgery

Scope of the talk1. A broad outline of the scope of Surgical

Orthodontics and the Orthodontist’s role in it.

2. Suggestions to avoid the pitfalls in planning the treatment and executing its orthodontic management

3. Preparation of a surgical splint using a new gadget.

Limitations of Orthodontics – Several conditions which cannot be corrected by Orthodontics alone.

Limitations of Surgery

Indications1. Congenital anomalies

Indications2. Excessively large or small jaw dimensions

Indications3. Marked asymmetric jaw growth

Indications4. Anatomic limitations, which hinder the orthodontic tooth movement.

The spectrum of surgeriesa. Osteotomies –

• Le fort I, (Le fort II, or III in some cases)

The spectrum of surgeriesa. Osteotomies –

• Sagittal split osteotomy and osteotomy of the ramus (trans-oral or extra oral, vertical or inverted L)

The spectrum of surgeriesSurgically assisted expansion or contraction of

the maxilla

The spectrum of surgeriesSubapical surgeries

The spectrum of surgeriesChin Surgeries

The spectrum of surgeriesCosmetic surgeries

The spectrum of surgeriesDistraction osteogenesis

DIAGNOSIS

a. Deciding the need for Surgery

b. Deciding where the fault lies.

c. Quantifying the extent of the fault

Deciding the need for surgery: a. Congenital or developmental craniofacial

anomalies.

b. Abnormal jaw growth causing marked visible facial disfigurement.

c. Standard deviation as the yardstick

Deciding the need for surgery:

d. Orthognathic surgery in most instances is

elective.

Patient’s opinion plays a decisive role.

Excess mandibular growth is considered more obnoxious in our society.

Persons with mild prognathism often seek treatment, while those with moderate mandibular deficiency may refuse surgical correction.

e. Age considerations.

f. Patient’s self image.

How to locate the fault?• History

• Clinical examination

• Study models

• Photographs

• radiographs

The advantages and shortcomings of both

orthodontics and cephalometrics should be

thoroughly understood.

Clinical examination

a. Visual esthetic appraisal .

b. Functional analysis.

Visual Esthetic Appraisal

Relationship of facial structures with respect to their balance, symmetry, and proportions in all the three planes of space.

Visual Esthetic Appraisal- Frontal

1. Assessment of facial proportions.

Visual Esthetic Appraisal - Frontal

2. Facial Symmetry

Visual Esthetic Appraisal - Frontal

3. Canting of bilateral structues, specially the lips and the dentition

4.Lip Competence, exposure of upper incisors

Visual Esthetic Appraisal - Profile

1. Assessment of angles such as the facial angle of convexity, nasolabial angle, etc.

2. Lips in relation to various esthetic lines

3.Perpendicular distance between the subnasale and the chin.

4. Cheek – Bone contour.

Cephalometric Analysis

Precautions while taking cephalograms

1. Condyles properly seated in the fossae.

2. Lips fully relaxed.

3. Recording in the ‘Natural Head Position’

Precautions while doing analysis

1. Use of normative values not very appropriate, since they cannot be accurately applied to different ethnic groups, males and females, persons with varying builds, etc.

Precautions while doing analysis

2. Norms based on hard tissues alone also not appropriate due to the varying thickness of the soft tissues.

Cephalometric Analysis Precautions while doing analysis

3. It is better to consider as many measurements related to a particular structure. For ex: To evaluate the maxillo-mandibular relationship, measurements such as LNAPog, Wits, projections of points A and B on FH and palatal plane etc. alongwith the customary LANB

4. Instead of relying on absolute linear measurements, projected values are more meaningful.

a. Size

b. Placement

c. Orientation

6. Effect of vertical displacements on the sagittal relationship must be taken into account.

Cephalometric Analysis Useful readings - Sagittal

Maxilla: L SNA, A perpendicular to N perp.on the true horizontal, Size of maxilla in relation to the SN length, placement of its posterior limit with respect to sella.

Cephalometric Analysis Useful readings - Sagittal

Mandible: L SNB, B perpendicular to N perp.on the true horizontal, Size of corpus in relation to the SN length, ratio of ramus to corpus angle, placement of condyles, chin placement with respect to point B and Down’s facial angle.

Cephalometric Analysis Useful readings - Vertical

a) Jarabak ratio

b) Mandibular plane wrt SN and FH

c) Linear measurements of the incisors to their corresponding jaw bases

Cephalometric Analysis Useful readings - Vertical

d) Basal plane angle.

e) Maxillary inclination angle

f) PNS-Ethmoid point and ANS-Nasion.

Cephalometric Analysis Transverse dimension

Grummon’s analysis is a useful analysis to assess transverse dysplasia. Normative data for the Indian population is being worked out in our institution.

Quantification of the fault This step involves the determination of the

precise magnitude of surgical alteration of the jaw bases in a 3-dimensional perspective.

Quantification

Clinical exam Cephalometrics

Quantification of the faultCephalometric Assessment

a) Comparison with normative values

b) Assessment using certain established ratios

c) Surgical VTO

a) Comparison with normative values.

Burstone and Legan’s analysis

Drawbacks of Burstone and Legan’s analysis:1) Data was derived from a small sample

belonging to the Caucasian population.2) The ‘surrogate’ horizontal plane may give

erroneous inferences.

3) Mean values applicable to the average size individuals only.

B) Useful ratios:

1) SN: Maxilla: Mandible = 20:14:21

2)Corpus:Ramus = 7:5

3) Middle face : Lower face = 45 % : 55%

4) Postr : Antr face height(Jarabak)=62– 64%

5) Nasal : Labial = 1:4( Nasolabial angle )

Surgical VTOSoftwares

1) Dentofacial Planner

2) Vistadent

Pre-Surgical OrthodonticsA. Decompensating the incisor positions

Pre-Surgical OrthodonticsB. Alignment of teeth by decrowding.

Extraction pattern differs from that in camouflage.

Pre-Surgical OrthodonticsC. Incisor intrusion done pre-surgically if an

increase in the anterior face height is not desirable

Pre-Surgical OrthodonticsD. Arch forms are corrected so that the arches

are compatible with each other when surgically repositioned.

Pre-Surgical OrthodonticsE. In case of segmental procedures, apices of

teeth on either side of the cut are divergent or parallel.

F. Extraction spaces not closed completely.

Pre-Surgical OrthodonticsAppliance Selection

1) Edgewise ( Standard or Pre-adjusted )

2) Tip-edge

3) Begg appliance ( Good quality brackets )

Pre-Surgical OrthodonticsOther Considerations

A. Third molar extractions

B. Stabilizing wires

C. Model surgery and splint preparation

Post-Surgical OrthodonticsCorrection of minor deficiencies can be tried

immediately after the surgery using elastic forces.

Eg: Uneven midlines,

Minor canting of occlusal plane

Post-Surgical Orthodonticsa) Closure of remaining spaces

b) Acheivement of proper interdigitation

c) Finishing and detailing to satisfy the functional occlusal criteria.

Preparation of Surgical Splints

Surgical splints Intermediate

Thank you

For more details please visit www.indiandentalacademy.com

surgical orthodontics diagnosis / orthodontic courses by indian dental academy

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