US5342202A — Method for modelling cranio-facial architecture

Claim 1

Independent Claim 375 words

Process for modelling the cranio-facial architecture from a lateral cephalometric X-ray by determining the bony points and plotting straight lines for analysis, characterised in that a lateral X-ray of the cranium to be analysed is taken and: the following points P1, P2, P3 . . . P16, P17, P18, P19 are determined on the X-ray; the straight line D1 passing through points P1, P2, the straight line D2 passing through points P3, P4, and the straight line D3 passing through points P1, P3 are plotted; point P15 is determined as the intersection between the straight line D3 and the posterior cranial contour; point P16 is determined as the base of the line taken through the point P15 and perpendicular to the straight line D1; the angle (P3, P11, P12) is compared with 180°; the sectors (P3, P11) and (P11, P12) are compared; the sectors (P1, P5) and (P16, P5) are compared; the straight line D4 passing through point P9 and tangential to the cranial contour at point P14 is plotted; the straight line D5 parallel with the straight line D3 passing through point P9 is plotted; the angle γ between the straight lines (D5, D4) is measured; the algebraic sign (positive or negative) of the angle γ is determined; the diagram is classified as a cranial flexion model if (P3, P11, P12)<180° (P3, P11)<(P11, P12) (P1, P5)<(P16, P5) γ positive and is a cranial extension model if (P3, P11, P12)>180° (P3, P11)>(P11, P12) (P1, P5)>(P16, P5) γ negative the above points being defined as follows: P1: point M--naso fronto maxillary P2: point CT--temporo condyle P3: point Clp--upper and posterior clinoid process P4: point Od--posterior odontoid P5: point Cp--posterior condyle P6: point Np--naso palatine P7: point Br--bregma P8: point Pts--upper pterygoid P9: point ENA--anterior nasal spine P10: point Na--nasion P11: point SSO--spheno basilar symphysis P12: Ba--basion P13: point O a --upper odontoid P14: point O b --lower occiput P15: intersection of the cranial contour and the extension of the straight line passing through points P1 and P3; P16: base of the line taken through point P15 and perpendicular to the straight line passing through points P1 and P2; P17: point M e --menton P18: point F M --maxillo frontal P19: point P ti --posterior nasal spine.

Claim 2

Dependent Claim 375 words

Process for modelling the cranio-facial architecture from a lateral cephalometric X-ray by determining the bony points and plotting straight lines for analysis, characterised in that a lateral X-ray of the cranium to be analysed is taken and: the following points P1, P2, P3 . . . P16, P17, P18, P19 are determined on the X-ray; the straight line D1 passing through points P1, P2, the straight line D2 passing through points P3, P4, and the straight line D3 passing through points P1, P3 are plotted; point P15 is determined as the intersection between the straight line D3 and the posterior cranial contour; point P16 is determined as the base of the line taken through the point P15 and perpendicular to the straight line D1; the angle (P3, P11, P12) is compared with 180°; the sectors (P3, P11) and (P11, P12) are compared; the sectors (P1, P5) and (P16, P5) are compared; the straight line D4 passing through point P9 and tangential to the cranial contour at point P14 is plotted; the straight line D5 parallel with the straight line D3 passing through point P9 is plotted; the angle γ between the straight lines (D5, D4) is measured; the algebraic sign (positive or negative) of the angle γ is determined; the diagram is classified as a cranial flexion model if (P3, P11, P12)<180° (P3, P11)<(P11, P12) (P1, P5)<(P16, P5) γ positive and is a cranial extension model if (P3, P11, P12)>180° (P3, P11)>(P11, P12) (P1, P5)>(P16, P5) γ negative the above points being defined as follows: P1: point M--naso fronto maxillary P2: point CT--temporo condyle P3: point Clp--upper and posterior clinoid process P4: point Od--posterior odontoid P5: point Cp--posterior condyle P6: point Np--naso palatine P7: point Br--bregma P8: point Pts--upper pterygoid P9: point ENA--anterior nasal spine P10: point Na--nasion P11: point SSO--spheno basilar symphysis P12: Ba--basion P13: point O a --upper odontoid P14: point O b --lower occiput P15: intersection of the cranial contour and the extension of the straight line passing through points P1 and P3; P16: base of the line taken through point P15 and perpendicular to the straight line passing through points P1 and P2; P17: point M e --menton P18: point F M --maxillo frontal P19: point P ti --posterior nasal spine.

Claim 3

Dependent Claim 56 words

Process according to claim 1, characterised in that: the angle β is measured=(D1, D3); the angle δ=65° is taken as the constant angle; the angle γ is measured=(D5, D4); the sum of angles β, δ, γ is calculated; the straight line D6 originating at P18 and forming angle β+γ+δ with the straight line D3 is plotted.

Claim 4

Dependent Claim 51 words

Process according to claim 2, characterised in that: the straight line D8 passing through P18 and P6 is plotted; the angles D6 D3 and D8 D3 are compared; it is concluded that there is facial flexion if D6 D3>D8 D3; it concluded that there is facial extension if D6 D3<D8 D3.

Claim 5

Dependent Claim 40 words

Process according to claim 2, characterised in that: the straight line D7 passing through P9 and perpendicular to D5 or D4 is plotted depending on whether γ<-4° when D7 is perpendicular to D4 γ>-4° when D7 is perpendicular to D5.

Claim 6

Dependent Claim 211 words

Process according to one of claims 2 to 4, characterised in that: the straight line D7 is plotted to calculate the ideal vertical equilibrium of the two stages of the face: the upper stage (measured between point P10' and point P9) representing 45° of the total height of the face; the lower stage from point P9 is calculated as being 55% and this measurement is compared with the corresponding level of the chin P17' (P17 projected onto the straight line D7), D7 being plotted perpendicular to D5 from P9; if the facial model is a flexion model, when the angle γ is positive, this theoretical ratio is not modified if point P9 is located below or on the straight line D5, however, if point P19 is located above the straight line D5, a vertical correction of the position of P9 is made: the three points P14, P13 and P19 are projected orthogonally onto D5, the average height being that of P9; when the ideal vertical level on the chin is calculated, this measurement is compared with the corresponding level on the actual chin P17': and it is concluded that: there is facial flexion if P17' is below the ideal level; there is facial extension if P17' is above the ideal level.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-08-29	1998-02-28	1998-08-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-08-29	2002-02-28	2002-08-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-08-29	2006-02-28	2006-08-30	$7700.00	Window Closed / Lapsed

Method for modelling cranio-facial architecture

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