This document discusses dental composite materials, including their chemical and light activation methods, filler types, and shrinkage properties. It provides information on methyl methacrylate and Bis-GMA as common resins, as well as camphoroquinone and tertiary aromatic amines as typical photoinitiators and light absorbers. Details are given on densified and microfine composites, with filler particles less than 3 micrometers. The concepts of C-factor and methods to reduce composite shrinkage stresses at the tooth restoration interface are also summarized.

2. YASSER ALI AL MORTADA AL WASIFI
BDS, MSc, PhD, DDS.

17. Quoted from: S.C. Bayne, School of Dentistry, University of Michigan, Ann Arbor, MI

23. METHYL METHACRYLATE
BIS - GMA

32. CHEMICAL ACTIVATED (1) LIGHT ACTIVATED (1)
ACTIVATOR: Benzoyl Peroxide
Ultra Violet (365 nm)
Visible Light (460–480 nm)
INITIATOR: Tertiary aromatic amine Camphoroquinone
LIGHT
ABSORBER:
---
Benzoine methyl ether for UV.
Alpha diketone (aliphatic amine) for VLC.

33. CHEMICAL ACTIVATED LIGHT ACTIVATED
FORM: Two paste system One paste system
MIXING: Mix equal parts ~ entrapped air voids Readily available with no mixing
WORKING TIME: Limited Flexible
SETTING:
Start upon mixing
Extended until consuming all initiator
Command
Extended until light emission stopped
CONVERSION: Homogenous maximum curing
Un-homogeneous
Affected by time and depth of light

34. CHEMICAL ACTIVATED LIGHT ACTIVATED
COLOR
REPRODUCTION:
Poor quality of color reproduction High quality of color reproduction
TECHNIQUE
SENSITIVITY:
Only limited working time Problems with ambient light

51. Quoted from: S.C. Bayne, School of Dentistry, University of Michigan, Ann Arbor, MI

59. COMPOSITE TYPE FILLER
Densified composites: - Midway filled
Ultra-fine
Fine
< 60% by volume
Particles < 3 μm
Particles > 3 μm
- Compact filled
Ultra-fine
Fine
> 60% by volume
Particles < 3 μm
Particles > 3 μm
Micro-fine composites: - Homogeneous
Average particle size = 0.04 μm
- Heterogeneous
Miscellaneous Composites: Blends of densified and micro-fine composites
Traditional Composites Equivalent to what are termed macro fill composites in
other classifications
Fiber Reinforced Composites: Industrial-use composites

61. Quoted from: S.C. Bayne, School of Dentistry, University of Michigan, Ann Arbor, MI

67. Quoted from: https://www.kerrdental.com/kerr-restoratives/premise-universal-nanofilled-composite

68. Quoted from: 3M ESPE, Filtek Supreme Ultra Technical Product Profile

152. free shrinkage

153. LOW C-FACTOR
Effective shrinkage will
be toward the cavity
walls

154. HIGH C-FACTOR
Before Polymerization

155. HIGH C-FACTOR
Pre-Gel Phase

156. HIGH C-FACTOR
Post-Gel Phase

157. HIGH C-FACTOR
Post-Gel Phase

158. HIGH C-FACTOR
This resulting in white line at the tooth restoration interface denoting de-bonding

159. HIGH C-FACTOR
In such a case, to reduce the C-factor:
1. Lining with GIC or flowable composite
2. Incremental packing in vertical or oblique pattern
3. If it is difficult, split the horizontal increment