Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-01-20, 13:53:08 | version 1.38.0
10 I I studies _ comparison of three methods of therapy was chosen for the anterior tooth area in the initial years (one tooth width for TR and three tooth widths for RER). In later years, the cross-cut was replaced by a flap. After opening and bone exposure in the peri- apical area, the bone was penetrated with an elon- gatedturbinebur(#H1-018,Komet)andoccasionally with a bud bur and handpiece with water-cooling fromtheunit.IfcurettageorRERwasplanned,thebur openingwasenlargedand,inthecaseofRER,theroot tip was cut to a flat bevel of approximately 3mm. RadiographicdiagnosisbeforeRCTwasperformed according to five criteria: 1. apex without pathological findings 2.apex likely without pathological findings and with periodontal gap enlargement 3. AP of < 25 mm 4. AP of 25–50 mm 5. AP of > 50 mm. The AP dimension was measured as follows: the longestAPdimensionparalleltothetoothaxismulti- pliedbythelargestdimensionverticaltothis.Thefol- low-up radiographs (Radiograph 3), single-tooth ra- diographsonly,wereevaluatedaccordingtothreecri- teria: 1. apex without pathological findings and AP com- pletely healed 2. apex not determinable, AP incompletely healed, suspicionofscar,andperiodontalgapenlargement 3. failure: AP unchanged, enlarged, newly developed. RadiographswereevaluatedincasesinwhichRCT dated back one year or more. The radiographs were viewed and evaluated by three independent experts independently: Prof. J. Klammt (oral surgeon), Dr E. Goffart (30 years of experience, frequently acts as a forensic dental expert) and the author himself (40 years of experience). A 2× and a 7× magnifier with a 0.1mm scale were used. The two independent experts had never worked according to the N2 method. The majority opinion wasappliedfordefiniteradiographicdiagnosis.Inthe case of three different opinions, the mean diagnosis was valid. In cases of uncertain evaluation of a radi- ograph, the worse diagnosis was chosen. Failures with an accompanying radiograph were indicated as Failure 2 and clinical failures (pain, swelling, fistula) without a follow-up radiograph as Failure 1, which mostly resulted in re-interventions (EX, RER, RV, TR). Regardingradiographicdiagnosis,thelevelofagree- mentbetweentheexpertswasdeterminedaccording to Cohen’s kappa. A high level of agreement was achieved, with the following kappa values: 0.74 for Prof.Klammt,0.73forDrGoffartand0.63fortheau- thor. Independentoftheexistenceordiagnosisofafol- low-upradiograph,survivalrateswerecalculatedus- ing various target criteria. As the terminal point of survival,thedateofthelastappointmentintheprac- tice without previous re-intervention was added to DP. Thereafter, the new survival cycle ended after the results of a re-intervention. The failure rate calcula- tions were based on those 1,720 cases that returned to the practice after RCT with or without follow-up Radiograph. Failure 1 rate concerning acute exacer- bationsrelatedtothetotalof1,720cases,andFailure 2 rate to cases with follow-up Radiograph. ThedatawasenteredintotheSPSSstatisticalsoft- ware package (Version 10.0; SPSS) and the survival probability was calculated according to the Ka- plan–Meiermethod.Anerrorprobabilityof<0.05be- tween the examined parameters was determined as being statistically relevant. _Results Themalesexaccountedfor880ofthe1,720cases analysed (51.2%) and for 37 of the 87 acute exacer- bations(42.5%).Thedifferencebetweenthemaleand roots1_2015 Follow-up radiographic diagnosis Failure 2 rate Follow up 1 2 3 n n % n % n % n % AP: no NsRCT 205 167 81.5 22 10.7 16 7.8 17 8.3 RER 130 108 83.1 14 10.8 8 6.2 10 7.7 TR 165 146 88.5 15 9.1 4 2.4 10 6.1 TOTAL 500 421 84.0 51 10.0 28 5.6 37 7.4 AP: yes NsRCT 148 90 60.8 35 23.6 23 15.5 27 18.2 RER 357 264 73.9 34 9.5 59 16.5 60 16.8 TR 157 120 76.4 14 8.9 23 14.6 25 15.9 TOTAL 662 474 71.6 83 12.5 105 15.9 112 16.9 Table 2_Follow-up radiographic diagnosis and Failure 2 rate in relation to the presence of initial AP. Table 2 Follow up 123 AP: no NsRCT 20516781.52210.7167.8178.3 RER 13010883.11410.886.2107.7 TR 16514688.5159.142.4106.1 TOTAL 50042184.05110.0285.6377.4 AP: yes NsRCT 1489060.83523.62315.52718.2 RER 35726473.9349.55916.56016.8 TR 15712076.4148.92314.62515.9 TOTAL 66247471.68312.510515.911216.9