” This technique offers great potential because it can be employed in a wide variety of clinical situations, both when the anatomy is preserved and the direct version of the technique is applied and when substance has been extensively lost, in which case the indirect or partial version of the technique is to be used.
Restoring one part of the original anatomy, or a portion of it, permits to have a useful reference for the direct finalization of the restoration, provided that a number of minimum requirements are met:
- a minimally preserved, usable anatomy;
- a portion which extends on at least three stable points;
- three stable points for the correct positioning in space of the HARM matrix.
This technique is indicated for:
- minimally invasive lesions and occlusal pits,
- class I lesions,
- class II lesions,
- complex lesions,
- compound lesions,
- lesions that need a total covering both of working cusps and of balancing cusps,
- endodontically treated dental elements that are intact when starting the technique.
Despite its conceptual and practical simplicity, this technique permits to solve several and complex issues at the same time:
- The original occlusal anatomy is preserved in a loyal way;
- The lateral and interproximal original anatomy is loyally preserved. The technique proves very helpful in identifying the correct and harmonious curvilinear progression of interproximal spaces of Class II cavities. No other matrix, alone, can achieve this. In the HARM technique, the matrix provides the necessary thrust to compress the material that has been gently laid, preventing gaps and bubbles. Furthermore, this is the easiest way to push and support the metal matrix that is seated in such a way as to obtain the most from the inserted wedge and the burnishing of the matrix. As a matter of fact, with large and deep Class II cases, often the contact point in the end is too weak or insufficient due to the difficulty of holding the matrix in place while curing;
- Good gnathological result, while avoiding underocclusion or lacking restorations;
- Precision of details because the matrix – that has been obtained from the original positive and not from a stone cast (indirect method from a non original positive) offers details that no other type of modelling can provide;
- Operating simplicity. Hypothetically, if the matrix were perfectly repositioned and if there were a perfect balance between the composite material that has been added and the dental material that has been removed, a restoration could be finished in a few steps and without any need for finishing or for touch-ups. And yet, this result can be rarely attained. Indeed, if the balance is not reached, this might cause gaps or defects that are not so significant if they concern the mass or if they are far from dental structures, but which become critical if they coincide with the cavity margins. This is the reason why you need to add very little surplus material, so as to obtain a safe repositioning and an equally reassuring outflow. Such outflow indicates that the material has reached all places based on Pascal’s principle. If anything, this might create a minimal bump that can be easily handled;
- Optimal curing: the HARM matrix provides, at the same time, an optimal, oxigen-free environment which can interact and inhibit the full conversion of double bonds and which is nevertheless sufficient; its opacity can be easily handled by the more powerful, modern light sources and in the subsequent steps of a prolonged curing procedure. A cycle lasting 1 minute will be therefore sufficient to obtain a good curing, which is always perfected in the end by performing a number of cycles, from various directions. “
To see the complete case report and follow all the Harm Technique steps, please look at the attachment.