PURPOSE: To evaluate the clinical implications of scallp penumbra width that comes from multileaf collimator(MLC) effect by the daily routine patient setup error. MATERIALS AND METHODS: The angles of 0degree, 15degree, 30degree, 45degree, 60degree and 75degree inclined-radiation blocked fields were generated using the both conventional cerrobend block and the MLC. Film dosimetry in the phantom were performed to measure penumbral widths of differences between the dose distributions from the cerrobend block and those of respect the MLC. The patient setup error effect on scallop penumbra was simulated with respect to the table of setup error distribution. Same Procedures are repeated for the cerrobend block generated field. RESULTS: There are penumbral widths of to 3mm difference between the dose distributions from two kinds of field shaping tools, the conventional block and the MLC with 4mm setup error model and resolution of 1cm leaf at the isocenter. CONCLUSION: We need not additive margin for MLC, if planning target bolume is selected according to the recommendation of ICRU 50. For particular cases, we can include the target volume with less than 3mm additive margin.
Film Dosimetry ; Humans ; Pectinidae*

PURPOSE: The purpose of this study was to assess the relationship between gingival biotype and underlying crestal bone morphology in the maxillary anterior region. MATERIALS AND METHODS: The maxillary anterior teeth from 40 subjects (20 thin biotype, 20 thick biotype) with ages from 20 to 50 years were included in this study. All subjects had healthy gingiva in the maxillary anterior region and had no history of orthodontic treatment, periodontal treatment, or hyperplastic medication. Using the probe transparency method, the scalloped distance (SCD) between the contact point-bone crest and the midface-bone crest was measured for each maxillary anterior teeth of two groups. RESULT: The mean SCD was 3.00±0.21 mm in thin biotype and 2.81±0.20 mm in thick biotype. The SCD value in the thin biotype was statistically significantly greater than in the thick biotype (t=2.982, P<0.01). Comparing the degree of crestal bone scallop in each maxillary anterior teeth in the two groups, all six teeth in the thin biotype showed higher bone scallop than in the thick biotype. CONCLUSION: A simple procedure using a probe could to determine gingival biotype and to predict the underlying crestal bone morphology was introduced. This may be useful for effective treatment planning.
Gingiva ; Maxilla ; Methods ; Pectinidae ; Tooth

PURPOSE: The Conformal Radiation Therapy has been widely used under favour of development of computer technologies. The delivery of a large number of static radiation fields are being necessary for the conformal irradiation. In this paper, we investigate dosimetric characteristics on penumbra regions of a multileaf collimator(MLC), and compare to those of lead alloy block for he optimal use of the system in 3-D conformal radiotherapy. MATERIALS AND METHODS: The measurement of penumbra by MLC or lead alloy block was performed with 6 or 10 MV X-rays. The film was positioned at a dmax depth and 10 cm depth, and its optical density was determined using a scanning videodensitometer. The effective penumbra, the distance from 80% to 20% isodose lines and 90 to 10 were analyzed as a function of the angle between the direction of leaf motion and the edge defined by leaves. RESULTS: Increasing MLC angle (0-75degree) was observed with increasing the penumbra widths and the scalloping effect. There was no definite differences of penumbra width from 80% to 20% isodose lines, while being the small increase of penumbra width of lead alloy block are agree reasonably with those of MLC within 4.8mm. CONCLUSION: The comparative qualitative study of the penumbra between MLC and lead alloy block demonstrate the clinical acceptability and suitability of the multileaf collimator for 3-D conformal radiotherapy.
Alloys* ; Film Dosimetry ; Pectinidae ; Radiotherapy, Conformal

PURPOSE: The Conformal Radiation Therapy has been widely used under favour of development of computer technologies. The delivery of a large number of static radiation fields are being necessary for the conformal irradiation. In this paper, we investigate dosimetric characteristics on penumbra regions of a multileaf collimator(MLC), and compare to those of lead alloy block for he optimal use of the system in 3-D conformal radiotherapy. MATERIALS AND METHODS: The measurement of penumbra by MLC or lead alloy block was performed with 6 or 10 MV X-rays. The film was positioned at a dmax depth and 10 cm depth, and its optical density was determined using a scanning videodensitometer. The effective penumbra, the distance from 80% to 20% isodose lines and 90 to 10 were analyzed as a function of the angle between the direction of leaf motion and the edge defined by leaves. RESULTS: Increasing MLC angle (0-75degree) was observed with increasing the penumbra widths and the scalloping effect. There was no definite differences of penumbra width from 80% to 20% isodose lines, while being the small increase of penumbra width of lead alloy block are agree reasonably with those of MLC within 4.8mm. CONCLUSION: The comparative qualitative study of the penumbra between MLC and lead alloy block demonstrate the clinical acceptability and suitability of the multileaf collimator for 3-D conformal radiotherapy.
Alloys* ; Film Dosimetry ; Pectinidae ; Radiotherapy, Conformal

PURPOSE: The peri-implant soft tissue is remodeled by the initial marginal bone resorption affecting the prognosis and esthetic result of treatment. Thus various designs on implant neck design are studied to preserve peri-implant bone. The purpose of this study is to review on the causes of initial marginal bone resorption, the configuration of peri-implant soft tissue, and the implant crestal module favorable in preserving peri-implant tissue. MATERIALS AND METHODS: The studies on the causes of initial marginal bone resorption and the implant crestal modules are researched and reviewed using Pubmed database. The implant crestal modules including one piece and two-piece implant, internal and external hex abutment, taper and butt joint connection, scalloped design abutment, and platform switching concept are reviewed. RESULTS: A number of clinical and experimental studies preferred one piece implant to two-piece in preserving initial peri-implant tissue. For two piece implants, internal hex abutment and taper joint connection appear more favorable than external hex abutment and butt joint connection relatively. Controversial issues still exist on scalloped design requiring more studies on it. Although the rationale is not certain, the concept of platform switching seems favorable in preserving initial peri-implant tissue based on clinical and experimental studies. CONCLUSION: Each implant crestal module contains its own advantages and disadvantages with various controversial issues. In the aspect of preservation of initial peri-implant tissue, however, one-piece implant seems beneficial. In cases when two-piece implant is more appropriate due to prosthodontic concerns or any other problems, the application of platform switching concept, internal connection abutment, and taper joint connection may be favorable for the preservation of peri-implant tissues.
Bone Resorption ; Joints ; Neck ; Pectinidae ; Prognosis ; Prosthodontics

The tricuspid valve is not a simple but a complex structure, tricuspid valve complex. This complex is composed of tricuspid orifice, annulus, valve leaflet, chordae tendineae and papillary muscles. There are flew articles about these structures. The authors studied tricuspid valve complex in 53 cases of normal korean adults, such as circumference of tricuspid annulus, the maximum diameter of the tricuspid orifice, height and breadth of the cusps, including commissures, the ratio of rough to clear zone, the number of scallops of posterior cusp, the number, length and pattern of arrangement of the several types of chordae, the number and morphological characteristics of papillary muscles.
Adult* ; Chordae Tendineae ; Heart* ; Humans ; Papillary Muscles ; Pectinidae ; Tricuspid Valve*

Advancement in imaging techniques and interventional cardiology procedures have generated renewed interest in anatomy of tricuspid valve complex. The purpose of the present study was to characterize the morphology of tricuspid valve leaflets using objective criteria. Thirty-six embalmed cadaveric hearts were utilized for the present study. Leaflet morphology was studied using newly defined criteria. Commissural zones were identified and leaflets were delineated. Presence of scallops was also recorded. Single leaflet was observed in six cases, double in 26 cases, and triple in four cases. The anterior leaflet is large with multiple scallops and frequently accrues portion of inferior leaflet. The septal leaflet is in the form of a plateau and also frequently accrues parts of inferior leaflet. The inferior leaflet rarely occurs as independent leaflet. A wide un-indented basal zone exists across the valve leaflets. The study found that the tricuspid valve is rarely tricuspid. It also generated the hypotheses that the tricuspid valve does not open completely due to presence of a wide basal zone and the valve does not close completely owing to incongruence and lack of coaptation of leaflets. The findings provide clear understanding of leaflet morphology of tricuspid valve. This will help imaging specialists for interpretation of images and cardiologists for interventional procedures. The findings also enhance our understanding of pathophysiology of conditions like functional tricuspid regurgitation.
Cadaver ; Cardiology ; Heart ; Pectinidae ; Specialization ; Tricuspid Valve Insufficiency ; Tricuspid Valve*

There are so many considerations for successful restorative dentistry and the periodontal consideration is one of the most important facors to consider. In modern dentistry intracrevicular margin is popular due to esthetic reason. But the marginal tissue recession after intracrevicular restoration is one of the most troublesome phenomena. The marginal tissue recession may be controlled with understanding the mechamsms. In conclusion (1) the inflammation of periodontium must be controlled before intracrevicular restorative percedure (2) the width and thicknes of keratinized gingiva must be evaluated before intracrevicular restorative procedure (3) tooth preparation must follow the natural scallop of CEJ.
Dentistry ; Esthetics ; Gingiva ; Inflammation ; Pectinidae ; Periodontium ; Tooth Cervix ; Tooth Preparation

The typical juvenile xanthogranuloma contains histiocytes with a variety of cellular features. Five types of juvenile xanthogranuloma have been described: vacuolated, xanthomatized, scalloped, oncocytic, and spindle-shaped. Spindle cell xanthogranuloma is a rare variant of juvenile xanthogranuloma characterized by predominance of spindle-shaped histiocytes. It occurs mainly in adults and less commonly in children. We report a case of spindle cell xanthogranuloma in a 4 month-old infant.
Adult ; Child ; Histiocytes ; Humans ; Infant ; Pectinidae ; Xanthogranuloma, Juvenile

Sebaceoma, also known as sebaceous epithelioma, is a rare, benign, adnexal tumor with sebaceous differentiation. It usually appears as a yellowish papule, nodule, or plaque on the scalp and face, on which there are abundant sebaceous glands. Histologically, it is a well-circumscribed lesion composed of undifferentiated basaloid cells and mature sebaceous cells in relatively preserved lobulated architectures. A 31-year-old woman presented with a 1.3-cm ×1.1-cm nodule on the right earlobe. Mohs micrographic surgery was performed to completely remove it. Histopathological examination revealed that mature sebaceous cells with scalloped nuclei and focal cystic change were present in the lobule.
Adult ; Carcinoma ; Female ; Humans ; Mohs Surgery ; Pectinidae ; Scalp ; Sebaceous Glands