DH220 Dental Materials

Lecture #13

Prof. Lamanna RDH, MS

Orthodontia

OrthodontiaDefinition: the specialty in dentistry concerned with the supervision, guidance and correction of all forms of the growing or mature dentofacial structures.

Responsibilities of the Orthodontist:

Diagnosis, prevention, interception and treatment of all forms of malocclusion of the teeth and surrounding structures.

Benefits ---- which become the indicators for ortho treatment

1. Psycho-social function - self-esteem.

2. Oral function – chewing, swallowing, speech, TMD

3. Dental disease – malocclusion can contribute to decay, perio disease, inadequate OH

Contraindications:

1. Lack of bony support

2. Rampant caries

3. Poor general health/mental health

4. Poor OH

5. Lack of interest, lack of cooperation

6. Lack of financial means

Angle’s Classification

• Class I

• Class II Div. 1

• Class II Div. 2

• Class III

Wilkins – chpt 16

Most common Ortho problems

• Crowded malaligned teeth

• Overjet

• Overbite

• Open bite

Causes: • Developmental: congenitally missing teeth, malformed teeth,

supernumery teeth, interference with eruption (i.e. impaction), ectopic eruption (located away from normal position)

• Genetic: Discrepancies in size of jaw and size of teeth – inherit small jaw from one parent and large teeth from another.

• Environmental: a. Birth injuries

▪ Fetal molding – limb of fetus presses against another part of body. Ex: arm is abnormally pressed against mandible, pressure distorts growing areas.

▪ Trauma during birth – usually due to forceps in deliveryb. Injuries throughout life

▪ Trauma to 1° teeth/premature loss of 1° teeth ▪ Direct injury to permanent teeth

• Functional:Sucking habits: thumb, tongue, lip, finger; abnormal tongue posture/activity (tongue thrust)

3 Phases:

1. Preventive – recognition and elimination of irregularities and malposition in developing dentofacial complex

• Caries control – avoidance of premature loss of 1° teeth resulting in loss of space for permanent tooth

• Use of space maintainers – saves space for permanent tooth

• Correction of oral habits

• Early detection of congenital anomalies

2. Interceptive - steps taken to prevent or intercede as they are developing

▪ Removal of 1° teeth that may be interfering with eruption/proper alignment of permanent teeth.

▪ Serial extraction of teeth – critical overcrowding of teeth – referred to DDS or oral surgeon.

3. Corrective ▪ Removable appliances

▪ Fixed appliances (cemented into place – not removable by pt)

▪ Orthognathic surgery – for severe cases

Mechanism of action of orthodontic appliances:

How does it begin? Diagnostic Records

• Study Models

• Photographs – extra/intraoral – front and side (profile) views

• Radiographs –

a. Panoramic films: broad view – pathology – impaction – supernumery teeth

* b. Cephalometric films: evaluatedentofacial proportions and clarify anatomic basis for malocclusion

Types of Appliances• Removable - primarily used as retainers or in “tipping teeth”.

Originally, not used for major tooth movement. Currently, more tooth movement can be accomplished with tray aligners.

– Retainers - Invisalign

• Fixed Appliances “Braces” attach to teeth and assist in tooth movement - Can be in (6) six directions: M, D, L, F, apically or occlusally - Can also be rotated on its axis (left or rt)

®

Applied force pointsMTM® Clear•Aligner

• Before attachments are places, soft brass wire separator or elastomeric ring separators are used to open tight interproximal contacts so the bands can be properly seated. - Brass 5 -7 days, elastomeric leave up to 2 wks.

Components of fixed appliances:

• Attachments – bands, brackets

• Auxillaries – head gear tubes, elastic hooks

• Arch wire – align dentition

• Ligatures – wire, elastomeric ties

Review of components:

1. Facebow - used to stabilize or move maxillary 1st molars distally and create more room in the arch.

2. Traction Devices - applies external force used to achieve desired treatment results.

* Review ortho diagrams in Dental Materials Lab workbook

E. HeadgearAn orthopedic device used to control growth & tooth movement. Two parts:

Oral Hygiene and Dietary concerns• Tooth Brushing: Charters method (45° at ging margin towards occ/inc

surfaces). Use interproximal brush to clean under arch wire. Multiple styles available that are more conducive to ortho.

• Flossing: Use bridge threaders

• Fluoride Rinses: Daily• Rinse with water frequently and thoroughly to remove food particles.

• Avoid hard foods, sticky foods - avoidance of band breakage or bending of archwires

4 more slides to go!!

• Removal of bands/brackets - goal: removal of bands/brackets & residual cement

with minimal damage to the tooth surface.

• Bands: Breaking seal of cement and lifting band off.• Brackets: Creating a fracture within the cement.

- post debonding: fluoride tx, √ for perio, dental caries

Debonding – read: Wilkins chpt 28

Retention Phase– Control of tooth position and occlusal relationship.

1. Ortho positioner 2. Hawley retainer

3. Lingual retainer

Specialized appliances:• Palatal expander – 2 styles:

- correction of crossbite and expands the maxilla

N.Y.S. Statutory Duties for RDH – July 10, 2003 Under the personal supervision of DDS regarding ortho:• Take impression for space maintainers, orthodontic

appliances, and occlusal guards• Place and remove temporary separating devices• Place and remove orthodontic ligatures• Prefit and place orthodontic bands• Remove orthodontic arch wires

New York State licensed dental hygienists must be able to perform these new supportive services and all other professional duties competently. Additional education and training may be required to competently provide these services. A dental hygienist attempting to perform these functions without training may be held liable to discipline. “Performing professional responsibilities” which the licensee knows or has reason to know that he/she is not competent to perform” is unprofessional conduct, according to Section 29.1 of the Rules of the Board of Regents.

Any Questions?