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Dental composites have now been used for many years,and practitioners have come to recognise their valuableproperties when trying to reproduce restorations that canbe regarded as truly aesthetic. And whilst compositescannot be used for all dental restorations, they are perhaps the best option where intra-oral conditions doallow their use.

The work of Dr VaniniDr Lorenzo Vanini is one of the world’s most respectedinnovators in dental composite technology, and his extensive work over the past 20 years has resulted in theintroduction to the dental market of the now well-established Enamel plus HFO range of restorative composites.

Dr Vanini developed a unique ‘build-up’ techniquethat utilised a systematic layering of composite materialsthat resulted in a much more realistic and natural appearance to both anterior and posterior directcomposite restorations, and reduced the sometimesobvious lines of demarcation that could be detected insome composite restorations. The same build-up techniques were also found to work effectively with indirect composite restorations produced in the dentallaboratory.

Enamel plus HFO compositesThe Enamel plus HFO range of composites offered thepractitioner and technician considerable scope of use, butit was not always possible to produce restorations thatwould both reflect and refract light in the same way asthat of natural tooth enamel. This is due to the somewhatdifferent refractive indexes of the natural enamel (n 1.62),and that of the composite (n1.51), and in an effort to tryand balance out the values of these, some users wouldadd extra composite enamel. This procedure tended toincrease the brightness of the restoration – the so-called‘glass effect’ – which did not always assist in rectifying thebalance of both reflected and refractive light, or in thedesired appearance of the restoration.

HRI enamelsA newly introduced composite enamel material, knownas HRI, has now addressed this problem.

The HRI enamels use high refractive index Nano-Zirconium Oxide particles (12%), together with aspecially developed silanisation process. The HRIenamels also contain a high refractive index glass filler(68%), and have a Vickers hardness of 700mpa, and aflexural strength of 13,500mpa.

There are three UE (Universal Enamel) shades that canbe used in conjunction with the regular Enamel PlusHFO Universal Dentine (UD) shades. UE1 is an amber-based shade, UE2 is a general-use enamel shade,and UE3 is intended for use with white or bleached teeth.

Advantages of HRIThe advantage that the HRI enamels offer can bedescribed as a ‘cloning’ of the natural enamel layer. TheHRI enamels possess the same light refractive index asthat of natural tooth enamels, and consequently they canbe applied over the dentine composite as a much thinnerlayer; this being virtually as thin as that of the naturaltooth enamel.

The use of the relatively intense HFO Opalescentshades, such as OA (Opalescent Amber), and OBN(Opalescent Blue Natural), will therefore be significantlyreduced, and these need only be used where a specificshade enhancement is required.

Use of the HRI enamels can also negate the need to usethe HFO ‘glass connecter’, as one of the functions of thismaterial was to balance light reflection and refractioneffects.

Dental professionals that are already familiar with

Enamel Plus HFO composites will find that the introduction of the HRI Enamels offers them new opportunities to further enhance the aesthetic quality ofall their composite restorations.

Tony Beale describes the new HRI composites thatproduce a true representation of natural tooth enamels

A new advance incomposite restorations

For those practitioners wanting to learn more about EnamelPlus HFO, the new HRI enamels and HFO technique courses,please contact Optident Ltd, International DevelopmentCentre, Valley Drive, Ilkley, LS29 8AL. Call 01943 605050, email char.billington@optident.co.uk or visitwww.optident.co.uk.

Figure 1: Central incisor prior to restoration with Enamel PlusHFO composite

Figure 2: Restored central incisor, showing use of HRI enamelsand the complete integration with the natural tooth enamel

Figure 3: New HFO composite kit showing HRI Universal Enamelshades (UE1, 2, 3), and note new dentine shades UD 0 and UD 0.5for bleached teeth