BY DR KHAWAJA RASHID HASSAN HEAD SCIENCE OF DENTAL MATERIALS DEPARTMENT W.M.D.C ABBOTTABAD

 Materials used in MAXILLOFACIAL SURGERY.  Materials used in ENDODONTICS.  Materials used in PERIODONTICS.

INTRODUCTION  Maxillofacial materials are used to correct facial defects. CAUSES OF FACIAL DEFECTS  Cancer surgeries.  Accidents.  Congenital deformities. NOSES, EARS, EYES, ORBITS & OTHER PARTS OF HEAD AND NECK REGION ARE REPLACED BY THESE PROSTHESES

PROSTHETIC EYEPROSTHETIC EAR

PROSTHETIC NOSE

 Following materials are used for the fabrication of maxillofacial prostheses. 1) POLYMETHYLMETHACRYLATE. 2) POLYURETHANE. 3) ROOM TEMPERATURE-VALCUNIZED SILICONES. 4) OTHER ELASTOMERS.

1) POLYMETHYLMETHACRYLATE:  P.M.M.A was once commonly used for maxillofacial prostheses.  Still used occasionally to make artificial facial parts.  Look quiet realistic once properly pigmented. Hardness & stiffness of P.M.M.A is the main disadvantage.

2) POLYURETHANE: a) Used as maxillofacial materials. b) Formed by the reaction of diisocyanate & polyol in the presence of an initiator. c) Reaction must be carried out in a dry atmosphere or carbon dioxide will result. d) Processing temperature of 100 ̊C is reasonable.

3) ROOM TEMPERATURE VALCUNISED SILICONES: a) Because of good physical & mechanical properties & favorable processing characteristics RTV-Silicones have become popular maxillofacial materials. b) Used more often than any other material for fabrication of maxillofacial prosthesis. c) They are easy to color.

4) OTHER ELASTOMERS: a) Several elastomers have been investigated for use as maxillofacial materials, including b) Aliphatic polyurethanes. c) Chlorinated polyurethane. d) Organophosphazenes. e) Silicone poly(methyl meth acrylate) block polymers.

Endodontics is concerned with the physiology, morphology & pathology of the human dental pulp & periradicular tissues Treatments include: a) Capping of exposed vital pulp. b) Sealing of root canal space after removal of infected pulp. c) Reconstruction with endodontic post & core systems in case of badly broken down tooth.

a) Vital pulp capping: Two types Indirect pulp capping Direct pulp capping  PULP CAPPING MATERIALS: 1) Calcium hydroxide cement. 2) Dentin bonding agents.

b) ROOT FILLING MATERIALS: Most widely used root canal filling materials are basically a combination of I. Obturating points & II. Canal sealer cements. I) OBTURATING POINTS A) Gutta percha points. B) Metal points.

A) GUTTA PERCHA POINTS: Gutta percha is a rubber obtained from the trees in Malaysia. Was introduced in U.K IN Thermoplastic material. Softens at ̊C & melts at about 100 ̊C. Cannot be heat sterilized but can be disinfected. Gutta percha when cooled rapidly forms a crystalline β phase whereas when cooled slowly a denser crystalline α phase is formed. α phase gutta percha has better thermoplastic characteristics and hence preferred to be used in hot gutta percha systems

OBTURA IIOBTURA III

COMPOSITION OF GUTTA PERCHA POINTS CONSTITUANTAMOUNT (%)PURPOSE GUTTA PERCHA19-22RUBBER ZINC OXIDE59-75FILLER HEAVY METAL SALTS 1-17RADIO-OPACIFIER WAX or RESINS1-4PLASTICIZER

B) METAL POINTS: Metals including gold, tin, lead & silver had been used as root canal filling materials. Silver points were used mostly because of bactericidal effect. Rigidity & ability to get corroded easily were the 2 main disadvantages of silver obturating points.

IDEAL PROPERTIES OF ROOT CANAL SEALER CEMENTS Should be biocompatible. Should be bacteriocidal or atleast bacteriostatic. Easy to use. Should be insoluble. Should be free of air bubbles when mixed. Floe to thin film thickness. Should adapt to the canal walls & obturating points. Should be radiopaque. Should be easily removed in case of failure.

ROOT CANAL SEALER MATERIALS:  ZINC OXIDE EUGENOL.  GLASS IONOMER CEMENT.  CALCIUM HYDROXIDE CEMENT.  POLY DI METHYSILOXANE.

PREFABRICATED POSTS:  Metal posts 1) Non threaded parallel sided posts. 2) Threaded parallel sided posts. 3) Non threaded tapered posts. 4) Threaded tapered posts.  Fibre reinforced resin posts 1) Carbon fibre reinforced posts. 2) Glass fibre reinforced posts.  Ceramic posts 1) Cosmopost. 2) Biopost. 3) Cetapost.

1) Zinc oxide eugenol formulation. 2) Zinc oxide fatty acid formulation. 3) Formulation including polyacrylic acid, poly ethyl methacrylate, zinc oxide, n-butylphthalate & alcohol.

GOOD LUCK FOR YOUR PROFESSIONAL EXAMZ