Periodontal condition A basic periodontal examination was recorded as shown below :
Table one : Periodontal examination
2 1 4 4 3 3
Occlusal examination Angles Class I anterior relationship showed a Class I molar relationship on the left and a Class I canine relationship on the right . The left and right lateral excursions were canine guided and protrusive guidance was provided by palatal surfaces of the maxillary incisors .
Dentition The dentition was heavily restored posteriorly on the left and with one occlusal restoration present on the right . The upper anterior incisors had porcelain-bonded crowns in situ .
Table two : Dentition
7 4321 1234567 7654321 1234567
Specific examination of the problem site ( LL4 ) Tooth LL4 was previously restored with a composite onlay in situ . Fitted in 2009 , it had a good marginal seal and good occlusal relationship with the maxillary teeth . Intercuspal relationship was noted and the buccal cusp was involved in left lateral excursions . There were no isolated periodontal probing defects , no signs of coronal or root fracture and the tooth was tender to percussion .
Table three : Special tests
SPECIAL TEST LL4 LR4
Digital axial / horizontal pressure
TTP-axial / horizontal
Digital palpationbuccal / lingual
Yes
Axial
Buccal / lingual
No
No
No
Endo-Frost No Yes
EPT No Yes
Periodontal probing
Within normal limits
Within normal limits
Fig 4
Radiographic examination A periapical radiograph taken at the emergency appointment revealed a marginally sound coronal restoration . A dentine pin appeared to be present in the distal of the tooth , with further evidence of some horizontal bone loss . A radio-opaque material was present in the root canal , which appeared sub-optimal and short of the radiographic apex , while the root appeared wide and a ledge was visible mid root with the obturating material . This suggested that two root canals were present with only one obturated . A periapical radiolucency was also apparent with some widening of the periodontal ligament space . ( Fig . 4 )
DIAGNOSIS AND TREATMENT PLAN Strictly speaking , a definitive diagnosis is only possible with a histological analysis of the infected area . However , the resources and facilities for this were not available . The diagnosis for the patient ’ s pain showed moderate , non-suppurative , localised , chronic apical periodontitis with a nonobturated root canal ( a failed primary root canal treatment ).
After discussing the benefits , limitations and risks of various treatment options including root canal treatment , extraction of teeth with prosthetic replacement and reducing infection with further observation , the patient opted for root canal retreatment under a private contract . Thereafter , consent was given and two subsequent appointments were made .
TREATMENT After the patient was questioned about known allergies , amoxicillin 500mgs tds was prescribed for five days . At the next appointment – which was 16 days later due to his work commitments – the restorability of tooth LL4 was discussed . Since the present restoration was well fitting and functional , it was decided to maintain this onlay and perform the root canal re-treatment through the occlusal surface . The patient was warned , however , that in the event that the onlay suffered damage as a result of the access cavity , he would require a new restoration . The possibility of a future full coverage crown was also discussed , and once the procedure was explained again for clarification , the patient
consented to treatment .
For the treatment itself , topical anaesthesia was first applied . After 60 seconds , a buccal and lingual infiltration was administered and a rubber dam was placed and sealed . An access cavity was then prepared through the existing composite onlay with the aid of x2 magnification surgical loupes . The obturation material was located buccally and identified as pink gutta-percha and subsequently removed with the aid of Gates Glidden burs , stainless steel files sizes 25 and 30 and solvent ( chloroform ).
The canal was irrigated copiously with 5.25 % heated ( 50 o C ) sodium hypochlorite ( NaOCl ). A radiograph was then taken to verify the working length ( 20mm from the occlusal surface ) and to confirm gutta-percha removal – since a zero reading had been achieved – with an electronic apex locator . Patency had also been achieved in the buccal canal . ( Fig . 5 )
Fig 5
The tooth was then assessed with the aid of a Carl Zeiss OPMI ** Pico operating microscope at x10 magnification and the remaining gutta-percha was removed . After locating the lingual canal , which was apparent on the initial radiograph , root dentine was removed with ultrasonic instruments . A working length was established as before and measured with an electronic apex locator , which was then verified with another radiograph . The lingual canal was again patent and had a working length of 19mm from the occlusal surface reference point . ( Fig . 6 )
Fig 6
To achieve straight-line access , being careful not to remove excessive dentine and restoration material , Gates Glidden burs were again used . Copious irrigation with
18 Dental Practice Magazine