도재 라미네이트의 절단면 피복 두께가 파절 강도에 미치는 영향 = The Study of Fracture Strength of Porcelain Laminate Veneer with Various Incisal Thickness when Incisal Restoring

국문 초록 (Abstract)

라미네이트를 설측 연장시 절단연부 두께에 따른 파절강도를 비교하기위해 우식이 없는 건전한 상악 중절치 60개를 선택하여 통상적인 치질 삭제를 시행하지 않고 절단연부위를 수평이 되게 삭제하고 순면에 seating form을 형성하고 가로 5mm X 세로 5mm X 두께 0. 9mm의 block을 형성하고, 설면연장 길이를1mm 되게끔 통일하고, 각군에 따라 절단부 두께를 Ⅱ군 0.5mm, Ⅲ군 1mm, Ⅳ군 2mm로 달리하여 block을 형성하여 레진으로 만든 individual tray를 이용하여 인상을 채득하여 내화모형을 제작후 거기에 도재를 통법대로 축성, 소성 하였다. block을 기준으로 하여 contouring을 시행하고 내화매몰재를 제거후 레진 시멘트를 이용하여 치아시편에 부착하였다. 이후 특별히 제작된 holding device에 시편을 부착하여 인스트론 만능 시험기로 파절 강도를 측정하여 다음과 같은 결과를 얻었다.
.각군의 평균 파절강도는 절연부 비 피개군에서 88.43Mpa, 절연부 0.5mm 피개군에서 30.65Mpa, 1.0mm 피개군에서 38.94Mpa, 2.0mm 피개군에서 59.22Mpa이었다.

다국어 초록 (Multilingual Abstract)

The purpose of this study was to evaluate the fracture strength of porcelain laminate veneer with various incisal thickness when incisal restoring.
Sixty recently extracted, intact maxillary incisors were used and stored in a physiologic saline solution from the time of extraction. Seating form was preparation at the labial surface of each tooth with a water-cooled round diamond bur.
Standard block was formed with 32 Gauge and 24 gauge wax at tooth labial and lingual surface. Incisal thickness differed according to each group. (group Ⅰ:0mm, group Ⅱ: 0.5mm, group Ⅲ:1mm, group Ⅳ:2mm)
All tooth specimens were impressioned with examix(GC Inc., Japan). Refractory cast were maked with refractory die material(Ceramco Inc., U.S.A.)
Laminate porcelain (Ceramco Ⅱ Veneer porcelain, Ceramco Inc., U.S.A.) was condensed in refractory die cast and baked according to the manufacturer's recommendations. Each surface was contoured with low speed diamond bur according to guide block.
All porcelain specimens were sandblasted and ultrasonically cleaned in distlled water for 3 minutes. Then, all porcelain specimen were etched with 8% hydrofluoric acid for 5 minutes. Sixty specimens were bonded with composite resin cement(Choice Porcelain Veneer System, Bisco Inc., U.S.A.) according to manufacture's directions.
The fracture loads of the specimen were measured by Instron universal testing machine. The mean values of fracture loads for the groups were statistically compared by Duncan's multiful range test.
The result were as follows:
Mean fracture strengths of each group were 88.43Mpa in no lingual extention group, 59.22Mpa in 2mm incisal thickness group, 38.94Mpa in 1mm incisal thickness group, 30.65Mpa in 0.5mm incisal thickness group.