Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

Non-working contact
A non-working contact is a contact between a pair of tooth sur-
faces on the non-working side during an excursive movement that
does not otherwise interfere with the smooth movement of the
mandible nor cause the guiding surfaces on the working side to be
separated.
Non-working interference (NWI)
A non-working interference is a contact between a pair of tooth 
surfaces on the non-working side, during an excursive movement,
that interferes with the smooth movement of the mandible and/or
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Chapter 1
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causes the guiding surfaces on the working side to be separated. It is
important to identify such contacts as they are thought to cause high
lateral loads on teeth and a subsequent predisposition to mechanical
failure of a restoration.
Any new restoration must be in harmony with the existing occlu-
sion if this is satisfactory. Where occlusal contacts are present that
may cause treatment difficulties or a predisposition to failure, then
steps should be taken to address this. For example, a cavity margin
might be extended to avoid a contact at the potentially weak tooth-
restoration interface or a non-working side interference reduced or
eliminated (Chapter 2). Similarly, where indirect restorations are
planned, these may be used to create a new occlusal relationship in
situations when the existing pattern is not satisfactory.
EXAMINATION OF THE DENTITION – CHARTING
A dental charting is a stylised record of the patient’s current dental
status. It is good clinical practice to record the dental status at initial
presentation and subsequent follow-up appointments. A full dental
charting should be recorded in all patients’ notes, thus forming part 
of the medico-legal record. It is not necessary to map the patient’s
restorations in detail on the charting, it is sufficient to record the type
of restoration and/or cavity, not its exact dimensional extent. The
object of a dental chart is to record:
• All teeth present.
• Teeth that are absent or unerupted.
• Presence and condition of existing restorations (including partial
dentures and bridgework).
• Presence and extent of dental caries and other dental abnormalit-
ies, (e.g. non-carious tooth tissue loss, fractures, developmental
defects and discoloration).