Food impaction associated with open contact causes more probing depth and clinical attachment loss interproximally than that associated with uneven marginal ridge. (1)
Food impaction affected patient's occlusion with the following frequencies; cusp to marginal ridge relationship (72.7%), cusp to fossa relationship (3.9%) and stepped relationship (23.4%).
There was also an improvement in the mean groove distance to the marginal ridge
between the initial and final skills practice, although this did not reach statistical significance (Table 1).
Turning to Scenarios Four and Eight, in these instances there was pain associated with the carious tooth with loss of marginal ridge and a sinus.
Indeed, there is currently debate concerning the indications for pulpal therapy when a primary molar is asymptomatic with some authors suggesting that a fractured marginal ridge alone is not necessarily an indication for pulpotomy treatment.
In the treatment choices selected for a mesio-occlusal cavity tooth 85 resulting in loss of more than half the marginal ridge, although with no clinical symptoms but an associated sinus for a non-anxious child patient, pulpectomy (calcium hydroxide and zinc oxide) was selected by 8/32 respondents whilst extraction with LA by 4/32 and other treatments by 6/32 postgraduates.
PG preferences for a patient with a mesio-occlusal cavity in tooth 85 resulting in loss of more than half the marginal ridge and with a history of pulpal pain and with signs of pulpal involvement with an associated sinus the preferred option was extraction.
The second most common reason was noted to be a failure was due to inadequate resistance form followed by fracture whether isthmus, bulk or marginal ridge
Loss of marginal ridge integrity has been reported as the greatest contributing factor to loss of tooth strength; thus, whenever possible the ridge should be preserved in order to maintain tooth strength [Mondelli et al., 1980; Reeh et al., 1989; Hansen et al., 1990].
This result implies that in FMT, what is important is preserving the marginal ridge, such that in 2-surface cavities, in which fracture strength is significantly higher than 3-surface cavities, the thickness of cavity walls does not play a significant role in increasing fracture strength, but in 3-surface cavities with loss of both marginal ridges, preserving more thickness in cavity walls can result in a significant increase to fracture.
The following criteria were measured: alignment, marginal ridges
, buccolingual inclination, occlusal contacts, occlusal relationships, overjet, interproximal contacts, and root angulation.
Clinically the distal marginal ridges
of posterior teeth and the incisal edges of the incisors determine the curve of Spee.3 The presence of curve of Spee of variable depth is a common finding in the occlusal arrangement of the dentition.