OBJECTIVE: To investigate the characteristic of cervical lymph node metastasis of pyriform sinus carcinoma. METHOD: One hundred and two pyriform sinus carcinoma patients who accepted treatments in the EENT Hospital of Fudan University from 1990 to 2006 were reviewed retrospectively. All of them did not have any treatment and received surgical treatment in our hospital. Stage was made according to the standard of International Union Against Cancer (UICC)in 1997. The distribution of cervical lymph node was confirmed by CT scanning and pathology. RESULT: The rates of lymph node metastasis were 16.7% , 59.4%, 70.8% and 63.6% for patients with T1 disease, T2, T3 and T4 (P <0.05), respectively, and 62.7% (64/102) for the whole patients. The bilateral metastasis rate were 2.70% (1/37), 12.5% (6/48) and 18.1% (2/11) for T2, T3 and T1, respectively (P <0.05). The occurrence of cervical lymph node metastasis was 3.87% in the level I , 33.55% in the level II, 30.97% in the level III, 25.16% in the level IV, 5.16% in the level V, 1.29% in the level VI (P <0.05). Fourteen patients with cN0 stage had modified neck dissection and 10 patients had lymph node metastasis (71.4%). The lymph node metastasis of cN0 and cN1 was all in the level II, level III and level IV. And cN2 and cN3 also had some in the level I, level V and level VI. CONCLUSION T2, T3 and T4 all had high rates for lymph node metastasis while T3, T4 were easier for contralateral metastasis. T3, T4 and contralateral metastasis were easier to surpassing the lymph node envelope. The lymph node metastasis of cN0 and cN1 was all in the level II, level III and level IV. And cN2 and cN3 also had some in the level I, level V and level VI.
Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Hypopharyngeal Neoplasms ; pathology ; Lymph Nodes ; pathology ; Lymphatic Metastasis ; Male ; Middle Aged ; Neck ; pathology ; Neoplasm Staging ; Pyriform Sinus ; pathology ; Retrospective Studies

OBJECTIVEThis study was about the influence of porcelain thickness on crack at interface.

METHODSThe effect of porcelain thickness on the flaw at the interface between porcelain and metal was studied in three groups with porcelain thickness of 0.5 mm, 1.5 mm and 2.5 mm (metal thickness of 0.5 mm) by means of moire interferometre and interfacial fracture mechanics. The parameter Jc was compared among the three groups and the growing of the flaw was observed.

RESULTSJc and the extreme strength of group with porcelain thickness of 0.5 mm (2.813 N/m and 9.979 N) were lower than those of the groups with porcelain thickness of 1.5 mm and 2.5 mm (5.395 N/m, 19.134 N and 5.429 N/m, 19.256 N). Flaws extend along the interface in the groups with porcelain thickness of 1.5 mm and 0.5 mm.

CONCLUSIONS(1) Fracture resistance of the interface in the groups with porcelain thickness of 1.5 mm and 2.5 mm is similar and it decreases in the group with 0.5 mm thick porcelain. (2) When porcelain is 1.5 mm or 0.5 mm thick, flaws will extend along the interface. When porcelain is 2.5 mm thick, flaws will extend into the porcelain layer.

Dental Porcelain ; Dental Stress Analysis ; Humans