Dental Framework

Cobalt-Chromium Framework

Cobalt-Chromium (Co-Cr) alloy dentures and cast partial dentures have been in common use since 1929, primarily due to their low cost and relatively lower density compared to gold alloys. Originally developed for aircraft engines and heat-resistant materials, Co-Cr alloys exhibit excellent mechanical properties such as strength, toughness, castability, corrosion resistance, and wear resistance.

Their corrosion resistance surpasses that of stainless steel, and their wear resistance outperforms both stainless steel and titanium alloys. However, their plasticity and workability are inferior to those of stainless steel and titanium alloys. Initially utilized for cast alloys due to processing challenges, these alloys generally consist of cobalt, chromium, and molybdenum, or cobalt, nickel, chromium, and molybdenum, sometimes incorporating other elements like tungsten or iron.

The primary Co-Cr alloy employed for biomedical and dental purposes is known as Vitallium. Comprising 65% cobalt, 30% chromium, and 5% molybdenum, among other substances, Vitallium is resistant to corrosion and finds applications in dentistry and the production of artificial joints. Cobalt–chromium alloys, along with nickel–chromium alloys, have been the main base metal alloys used in dental casting.

                    

Despite the similar required mechanical properties, such as a minimum proof stress of 500 MPa and a minimum elongation of 3.0%, cobalt–chromium alloys generally exhibit higher strength and hardness than nickel–chromium alloys. Consequently, cobalt–chromium alloys are primarily used for denture frameworks, while nickel–chromium alloys are applied to crowns and bridges. Notably, Co-Cr can now be milled or 3D printed, offering superior surface finish and a standardized product compared to traditional casting.

Advantages:

1. Cost-efficient
2. Lower density than gold alloys
3. Corrosion-resistant
4. Chemically inert
5. Good biocompatibility
6.Excellent hardness and tensile strength
7. Outstanding wear resistance

Mechanical Properties:

1. Yield Strength – 644 Mpa
2. Ultimate Tensile Strength – 869 Mpa
3. Young’s Modulus of Elasticity – 218 GPa

Applications:

1. Dental implant abutment
2. Partial denture framework
3. Fixed denture framework

 

PEEK Framework

Polyether ether ketone is a semi-crystalline, thermoplastic material. In recent years, it has gained considerable popularity over conventional metal frameworks due to its lucrative and resilient properties.

                        

PEEK frameworks have the highest aesthetic retention, along with resistance to scratching and abrasion. They are made from a biocompatible polymer of polyether ketone and are strengthened using ceramic. They’ve served in the field of body Implantology for over 30 years in the form of intervertebral discs, hip joints etc. With the improvement by ceramic fillers, these materials have found uses in dental applications, especially as a framework.

The stiffness and elasticity of these materials is very identical to the natural human bone, which reduces the effect of stress shielding around the implant and thereby increases its lifespan. The soft tissue adapts to the PEEK and creates microscopic connections which help in reducing the microbial leakage. These materials are approximately 8-9 times lighter than conventional metal and titanium frameworks. They possess no galvanic effects and do not cause a metallic taste in the mouth. They can absorb large amounts of load and would rather flex than break. Lastly, accidental fractures in the frameworks can be fixed by the chairside itself.                                 

Advantages:

1. Are anti-allergic – No metal, oxide or monomer in its composition
2. Weight and density are similar to the natural bone
3. Do not have a metallic taste
4. Off-peak effect – They reduce the compression and torsion caused by chewing
5. Heat conduction similar to teeth – increases comfort
6. Low abrasion and good versatility
7. Maximum customisability
8. Cuts similar to dentin
9. Conserving the antagonists
10. Optimal osseointegration
11. Optimal gingival management
12. Good longevity of the restoration
13. Natural oral feeling and chewing sensation
14. Natural aesthetics
15. Allows immediate restoration and is a one-time treatment
15. Is used as a framework, or custom abutment

Technical Data:

1. Flexural Strength – 180 MPa
2. E Modulus – > 4550 MPa
3. Wear Time – 9 years

Applications:

1. Long span fixed prosthesis. Especially implants and implant-tooth borne prostheses.
2. Repeated failure of implants or zirconia/metal prostheses.
3. Patients who are not comfortable or allergic to conventional material restorations.
4. Maxillofacial prosthesis and custom implants in cases of trauma and cancer rehabilitations.

 

Titanium Framework

Titanium, a metal extensively employed in the medical industry for decades, is recognized for its strength, lightweight nature, non-toxicity, and corrosion resistance. Dental implants crafted from titanium boast a remarkable long-term success rate of about 95%, a credit largely attributed to its exceptional biocompatibility stemming from the formation of a stable oxide layer on its surface.

                                

Commercially pure titanium (cpTi) is categorized into four grades based on differences in oxygen content. Grade 4 has the highest oxygen content (0.4%), while grade 1 has the least (0.18%). Mechanical variations among the different grades of cpTi primarily result from minute quantities of added contaminants. Iron enhances corrosion resistance, aluminium boosts strength while reducing density, and vanadium acts as an aluminium scavenger to prevent corrosion.

Titanium Alloys

Titanium, being a dimorphic metal, exists as its α-phase below 882.5 °C and transitions to its β-phase above this temperature. Its alloys can exist in alpha, beta, and α-β phases, depending on the quantity of added metals and the temperature of the reaction. Aluminium stabilizes the alpha-phase condition while enhancing strength and reducing alloy weight. Vanadium, on the other hand, acts as a beta-phase stabilizer. The temperature at which α to β transformation occurs shifts within a range as aluminium or vanadium is added to titanium. The most common alloy used for dental implants is of the alpha-beta variety, with Ti-6Al-4V being the prevalent choice, containing 6% aluminium and 4% vanadium.     

                                                                              

Advantages:

1. Strength and high flexural strength – resistant to fracture
2. Good bearing capacity leading to great longevity of restoration – can last > 30 years
3. Good osseointegration and soft tissue healing
4. Formation of passive oxide film on the surface resisting corrosion
5. Promotion of rapid bone formation and regeneration
6. High strength-to-weight ratio – lightweight and comfortable
7. Low thermal conductivity – less risk of pain or irritation from drastic temperature changes
8. Relatively painless implantation process
9. Doesn’t warp, bend, or buckle under pressure
10. Cost-effective in the long run

Mechanical Properties (Ti-6Al-4V):

1. Hardness – In the range of 179-185 VHN with a mean value of 182.16 VHN
2. Yield Strength – 982 MPa
3. Ultimate tensile strength – 1115 MPa
4. Compressive Yield Strength – 1074 MPa
5. Ultimate Compressive Strength – 1661.6 MPa

Applications:

1. Removable Partial Denture frameworks, Complete Dentures, and Overdentures
2. Fixed Partial Dentures
3. Implants in individuals with good bone strength and density
4. Oral & Maxillofacial Prosthesis

SAPTeeth Framework

By definition dental prosthesis is an intraoral (inside the mouth) prosthesis used to restore intraoral defects such as missing teeth, or missing parts of teeth. One of the most advanced materials for these artificial teeth are called SAPTeethTM. SAPTeethTM are a group of highly advanced polymers which are specially made to protect the bone, implant and the natural tooth under the prosthesis. 

Based on research it can be concluded that ceramic teeth, porcelain teeth, Ni-Cr teeth (metal teeth), titanium teeth exert stresses on the bone that are about 24 to 149 times more than SAPTeethTM. This difference is due to the shock absorbing capability of these polymers. Therefore, in patients with weak bone or low calcium, SAPTeethTM are recommended over conventional prosthesis specially for frameworks.

Why should you choose SAPTeethTM framework:

1. In case of crown breakage, the framework stays intact not affecting the natural teeth or implant underlying.
2. In case of infection in the underlying tooth or implant, the whole bridge need not be removed, only the relevant part may be treated. 
3. In case of habits like pan, supari or heavy bite or bruxism, the eating surface may get worn off but the re layering can be done at only a fraction of the price in less time. 
4. Apply 24 to 149 times less stress than conventional prosthesis which gives less load on the underlying bone.
5. Can be completed on the same day.
6. Long lasting with high impact shock absorption

TYPES of SAPTeethTM

SAPT.Resin: Produces safe, biocompatible, aesthetic temporary protheses that are required to be replaced by a higher performance polymer due to wear and tear.
SAPT.MC: Increase the wearing time of the temporary resin prothesis and can be used as an intermittent prosthesis. They offer even more polished aesthetics
SAPT.HIPC: It is a universal genius. They offer the most elegant, and varied solutions for a number of indications and can be used as a permanent prosthesis with an approved life span of 9+ years.
SAPT.3Dresin: Class 1 photopolymers biocompatible resins which are built from additive laser process to delivery surgical guides, and splits which can be fitted as a framework or temporary supports.
SAPT.CemResin: Flowable polymer which attached to the surfaces of the implant, natural teeth & high-performance polymers thereby creating a single unit for a more durable, success- oriented, & efficient dental prosthetic solutions.

Applications of SAPTeeth framework:

1. Single to multiunit prosthesis.
2. Full mouth rehabilitation cases.
3. Implant supported restoration especially in weak jaw bone conditions.
4. Monolithic or veneered fixed prosthesis.