Diamond Crown™ Composite Resin : a new light-curing material for

restorative and prosthetic dentistry.

Enrico Conserva, Paolo Pagliari and Danilo Schembri.

Albenga (Sv), Italy

The Diamond Crown™ composite resin (DRM Research Laboratories Inc, Branford CT, USA), is

a polyglass light-curing material composed of a phenolic- epoxyne matrix (PEX), glass-ceramic

silica filled, with a semi-crystalline microstructure (Figg.1,2) and excellent physical and mecha-

nical properties (Tab. I). This material is totally bio-compatible because does not contain any

cytotoxic metallic ion constituents, any evaporable methacrylic acid constituents or any chemi-

stry that yelds mucous membrane irritation, fibroblast changes, epithelial changes, microabces-

ses formation, lysis or haemolytic behaviour. The Diamond System is composed of 16 opaceous

dentin, 16 dentin ,16 enamel Vita shades and 6 incisal

shades with opacity unit values ranging between 5 OU

(incisal transparent) and 100 OU (metal opaque).

Fig.1: Polaryzed light microscope: PEX semicrystalline matrix.Fig.2:

Microphotograph of PEXsemicrystalline structure.

The Diamond Crown™composite material can be used both in restorative (Figg.3,4) and prosthetic dentistry (Figg.5,6). It is indicated for:

 Direct and indirect anterior/posterior teeth restorations

 Metal-composite crowns or bridges

 Metal-free composite crowns or max three-unit bridges

 Repairing resin or ceramic crowns

 Endodontically treated teeth restorations with posts

 Custom teeth for removable partial denture or full denture

Fig.3:Tooth 14 with Class II carious lesion.

 Fig.4: Tooth 1.4 with Class II Diamond

 Fig.5: Three unit bridge: metal framework.

 Fig.6: Three unit bridge: metal-Diamond

PURPOSE: The purpose of this study was to evaluate the clinical performance of the Diamond Crown™ PEX resin in metal-composite vs metal-free prosthetic restorations, in general practice, during a 18-month period.
MATERIALS AND METHODS: A number of consecutive metal-composite crowns (21) in 8 patients (2 women and 6 men) with a mean age of 50.5 years and of consecutive metal-free composite crowns (25) in 19 patients (10 women and 9 men) with a mean age of 39.1 years were made according to the Composite-Flask™ procedure in a 6-month period. All the crowns were cemented with Diamond Link™PEX cement and the patients were examined within a month after the permanent cementation (baseline).
The patients were recalled for clinical examination after 18 months (range 16 to 20 months) using the California Dental Association (CDA) criteria. The CDA system is a quality evaluation system in which each considered restoration parameter (Margin integrity, Color, Surface and Anatomic form) is given a rating in either of the two main categories: SATISFACTORY (with the subratings EXCELLENT and ACCEPTABLE) or NOT SATISFACTORY (with the subratings CORRECT and REPLACE). The data, collected by two examiners, were statistically analyzed with the t-test.

RESULTS: At the 18-month recall 20 of the original 21 metal-composite crowns and 23 of the original 25 metal-free composite crowns could be evaluated.The CDA scores are showed in percentages in the Tab.II and Tab.III. 

The statistical analysis (Tab.IV) performed with the T-test did not show statistically significant differences between the baseline evaluation and 18-month assessments.

Fig.7: Patient P.D. 31 year, male.

Tooth 16 two weeks after cementation of a metal-free crown.

Fig.8: Same patient at the 18-month recoll.

All parameter examined are SATISFACTORY. You can see the excellent marginal-gingival contour.

 DISCUSSION: The CDA clinical evaluation system is a useful but not objective instrument using more or less subjective criteria. From a clinical point of view, however, the discrimination between SATISFACTORY and NOT SATISFACTORY results could lead us to interesting considerations: the general failure rate in both groups (with and whitout metal) was low; during the 18-month period we observed no carious lesions, no Diamond Crown fractures, no debond of crowns, no separation from metal substructure and no separation between layers. The marginal integrity and the surface remained unchanged, however at 18-month recall a slightly dull or granular surface was registered (2 metal-composite crowns and 3 composite crowns with acceptable score). We believe that these excellent short-term results could be due to the innovative chemical structure of Diamond Crown™.
The commonly used Bis-GMA, UDMA, TEGMA, DecaMA composite resins have a "glass-like" amorphous structure , are brittle, weak and prone to fracture, to surface degradation and wear. The PEX semi-crystalline resin matrix ,microelastic and macrorigid, have an high toughness, high fracture resistance and optimal impact and wear resistance. In conclusion the Diamon Crown™composite system allows us to produce a quality prosthesis that was rated 100% SATISFACTORY and it maintain this high rating at least for 18 months, which was the duration of this investigation.

Fig.9:

Patient B.D. 46 years,female.

3- unit metal-free bridge and 2 single metal free crowns.

Fig.10:

Same patient after bridge and crowns cementation.

Figg.11 and 12:

Same patient, tooth 13 after cementation and at 18-month recall. All CDA parameters are EXCELLENT

Figg.13 and 14:

Same patient, tooth 14 after cementation and at 18-month recall. All CDA parameters are EXCELLENT

Diamond Crown™ Composite Resin : a new light-curing material for

restorative and prosthetic dentistry.

Enrico Conserva, Paolo Pagliari and Danilo Schembri.

Albenga (Sv), Italy

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