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Biomechanical and esthetic considerations for maxillary anterior overdenture abutment selection
ease
Ann Sue van Garter,
College of Denta”i Medicine, States Army Dental Activity,
Medical University Fort Biiss, Tex.
of South
Carolina,
Charleston,
SC.,
and United
have been selected as overde the use of maxillary canines maxillary lateral ilaeissre as he prosthesis, favora of the premaxilla. (9
inimlzing unfavorable forces directed toward the ~rern~~~~~ is a primary consideration in the planning and design of rna~i~~ary overdentures. When the edentulous ed by natural mandibular teeth or an immaxilla is plant-sup prosthesis, the potential for bone destruction is increased.“-” The retention of natural teeth as abut-
The opinions expressed or implied are strictly those of the authors and do not necessarily reflect the opinion or official policies of the Department of Defense or other Departments of the U.S. Govern-ment. aAssoeiate Professor and Director, Division of Removable Prostbodontics, Department of Prosthodontics, College of Dental Medicine, Medical University of South Carolina. “Major, Dental Corps, Assistant Director, Combined Prosthodontics Program, US. Army Dental Activity, Fort Bliss, Tex.
tissueundercuts and removal.
. Diverging placement
on facial aspect of canines present
obstacie to denture
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
NELSON
Fig. 2. Opposing undercuts (arrows) require extensive denture base alteration seating of prosthesis
without
discomfort
andpossible
AND
VON
GONTEN
to permit
soft tissue damage.
This article discusses maxillary anterior overdenture abutment selection as it relates to the fulfillment of anatomic, physiologic, esthetic, and hygienic requirements.
ANTERIOR
Horizontal Plane
Point Of Rotation Movement f
Sagittal Plane On
Point Of Rotation Fig. 3. A, Pronounced
anterior posterior rotation develops around fulcrum line in canine-supported maxillary overdenture. B, Occlusal loading causes rotation and disruption of peripheral seal anteriorly. C, Incisal loading produces rotation and loss of peripheral seal posteriorly. 134
ABUTMENT
SELECTION
Retaining maxillary canines as overdenture abutments may result in diverging facial tissue undercuts and produce an overcontoured denture base, excessive lip support, and possible discomfort associated with placement and removal of the denture (Fig. 1). Prominent canine eminentia also complicate the arrangement of the replacement teeth. Considerable cervical and lingual reduction of denture teeth is often required. The alveolar prominences mandate exaggerated facial positioning of the artificial teeth, compromising the esthetic result. When prominent canine eminentia are combined with alveolar undercuts in other areas of the maxilla, such as the buccal aspect of the tuberosities, the path of placement and removal of the prosthesis is further complicated (Fig. 2). These complications are routinely dealt with by providing internal relief of the acrylic resin denture base.3 This relief produces a weakened flange that no longer approximates the tissue, creates a food trap, compromises the peripheral seal, and predisposes the denture to fracture. Provision of adequate denture base material to allow for internal relief results in a disproportionately thickened denture flange, undesirable lip fullness, and distortion of the natural midfacial contours.g An alternative approach would be to shorten the denture flange, precluding extension into alveolar undercuts. Loss of peripheral seal and a weakened denture base become problems with this modification.g The displaceability of the supporting soft tissue permits denture base movement when the prosthesis is subjected to functional and parafunctional occlusal forces. Various fulVOLUME
72
NUMBER
2
Undesirabie diverging tissue undercuts are avoide ~~ote~ti~~y enhanced.
. 5. Abutments
are ideally dome shaped and contoured to ~~~~o~~~a~e~~ 2 mm a&we
crums are developed in the maxillary overdenture relative to abutment location. ~oveme~t toward or away from the residual ridge will occur as rotation about the fulcrum line when the overdenture is occlusally loaded (Fig. 3, A). This tion of the peripheral seal and perception of a loss of retention by the patient (Figs. 3, B and C). The magnitude of a~~ero~osterior rotation can be greatly seduced when fulcrum line passes through incisor teeth. axillary central incisors are ideally located in the arch pport, providing protection to the pre, they have several distinct disadvanhen adjacent abutments are used, the limited ince may make cleaning more difficult for the r&ion, the presence of two adjacent central incisors and their associated alveolar contours can result in an anterior prominence of the overdenture flange comproraising esthetics. Although the anterior location of maxillary central incisors is favorable, their proximity and alveolar prominence may complicate their utilization. Maxillary lateral mcisors offer advantages not realized with the use of the canine or central incisor teeth. Because
i-0 y&Je ‘,f laGer&l i,. of their vocation in the premaxiila, +Lrlv cisors in maintaining the integrity of t&e maxi1ia.q ~.teKiQ~ alveolar ridge is apprecia le. Iu csntrast co maxillary awtrai incisors, lateral incisors are wfdebj separ;j.tedP ~ac~~~~.a~~ ing plaque control. Tissue undercut pmblierms nosmal~y encountered with maxillary canines are waided when maxillary lateral incisors are used (Fig. 4). The alveolar contours of lateral incisors usua$ will not c~~~~~ca~e the path o~~~~ce~e~~ and r~~~~~~ of the ~~~~~~~~~~~ ~~.v~~~~~e esthetic results are readily at”tained, bemuse the bone on the facial aspect of lateral incisors is c~~~~~~~~~~ less prominent than the canine eminences. $3 a rem&, excessive lip support is avoided.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
NELSON
AND
VON
GONTEN
Point Of Rotat ion
Fig.6. Anteroposterior rotation through lateral incisor abutments
of prosthesis is diminished with fulcrum near anterior border of denture.
Stability and retention of the prosthesis are enhanced by the position of maxillary lateral incisors in the arch (Fig. 6). Clinical complaints of a loose maxillary overdenture caused by disruption in the integrity of the peripheral seal are potentially reduced.
SUMMARY The use of maxillary lateral incisors as overdenture abutments provides vertical support to the prosthesis, favorable stress distribution, and preservation of the alveolar bone. in the anterior maxilla. The esthetic result achieved with maxillary overdentures may be enhanced with the use of lateral incisors as abutment teeth. The position and accessibility of maxillary lateral incisors permit the patient to pursue a course of oral hygiene that maintains the supporting periodontium in an optimum state of health. REFERENCES 1. Kelly E. Changes caused by a mandibular removable partial denture opposing a maxillary complete denture. J PROSTHET DENT 1972; 27~140-50. 2. Lord JL, Tee1 S. The overdenture: patient selection, use of copings, and follow-up evaluation. J PROSTHET DENT 1974;32:41-51.
136
line located
3. Landa LS. Diagnosis and management of partially edentulous cases with a minimal number of remaining teeth. Dent Clin North Am 1985;29:3-16. prostheses for edentulous patients 4. Desjardins RP. Tissue-intergrated with normal and abnormal jaw relationships. J PROSTHET DENT 1988;59:180-7. complete 5. Saunders TR, Gillis RE Jr, Desjardins RP. The maxillary denture opposing the mandibular bilateral distal-extension partial denture-treatment considerations. J PROSTHET DENT 197%41:124-g. 6. Brewer AA, Morrow RM. Overdentures. 2nd ed. St Louis: CV Mosby, 1980:3-11. 7. Morrow RM, Brewer AA. Overdentures. 2nd ed. St Louis: CV Mosby, 1980:23-5. 8. Boone ME, Click JP. The use of maxillary centrals and laterals in the overdenture patient. Compendium 1987;8:748-54. 2nd ed. St 9. Winkler S. Essentials of complete denture prosthodontics. Louis: CV Mosby, 1988:384-402. 10. Tallgren A. The continuing reduction of the residual alveolar ridges in complete denture wearers: a mixed-longitudinal study covering 25 years. J PROSTHET DENT 1972;27:120-32. Reprint requests to: DR. DONALD R. NELSON DIVISION OF REMOVABLE PROSTHODONTICS DEPARTMENT OF PROSTHODONTICS COLLEGE OF DENTAL MEDICINE MEDICAL UNIVERSITY OF SOUTH CAROLINA 171 ASHLEY AVE. CHARLESTON, SC 29425
VOLUME
72
NUMBER
2
Ann Sue van Garter,
College of Denta”i Medicine, States Army Dental Activity,
Medical University Fort Biiss, Tex.
of South
Carolina,
Charleston,
SC.,
and United
have been selected as overde the use of maxillary canines maxillary lateral ilaeissre as he prosthesis, favora of the premaxilla. (9
inimlzing unfavorable forces directed toward the ~rern~~~~~ is a primary consideration in the planning and design of rna~i~~ary overdentures. When the edentulous ed by natural mandibular teeth or an immaxilla is plant-sup prosthesis, the potential for bone destruction is increased.“-” The retention of natural teeth as abut-
The opinions expressed or implied are strictly those of the authors and do not necessarily reflect the opinion or official policies of the Department of Defense or other Departments of the U.S. Govern-ment. aAssoeiate Professor and Director, Division of Removable Prostbodontics, Department of Prosthodontics, College of Dental Medicine, Medical University of South Carolina. “Major, Dental Corps, Assistant Director, Combined Prosthodontics Program, US. Army Dental Activity, Fort Bliss, Tex.
tissueundercuts and removal.
. Diverging placement
on facial aspect of canines present
obstacie to denture
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
NELSON
Fig. 2. Opposing undercuts (arrows) require extensive denture base alteration seating of prosthesis
without
discomfort
andpossible
AND
VON
GONTEN
to permit
soft tissue damage.
This article discusses maxillary anterior overdenture abutment selection as it relates to the fulfillment of anatomic, physiologic, esthetic, and hygienic requirements.
ANTERIOR
Horizontal Plane
Point Of Rotation Movement f
Sagittal Plane On
Point Of Rotation Fig. 3. A, Pronounced
anterior posterior rotation develops around fulcrum line in canine-supported maxillary overdenture. B, Occlusal loading causes rotation and disruption of peripheral seal anteriorly. C, Incisal loading produces rotation and loss of peripheral seal posteriorly. 134
ABUTMENT
SELECTION
Retaining maxillary canines as overdenture abutments may result in diverging facial tissue undercuts and produce an overcontoured denture base, excessive lip support, and possible discomfort associated with placement and removal of the denture (Fig. 1). Prominent canine eminentia also complicate the arrangement of the replacement teeth. Considerable cervical and lingual reduction of denture teeth is often required. The alveolar prominences mandate exaggerated facial positioning of the artificial teeth, compromising the esthetic result. When prominent canine eminentia are combined with alveolar undercuts in other areas of the maxilla, such as the buccal aspect of the tuberosities, the path of placement and removal of the prosthesis is further complicated (Fig. 2). These complications are routinely dealt with by providing internal relief of the acrylic resin denture base.3 This relief produces a weakened flange that no longer approximates the tissue, creates a food trap, compromises the peripheral seal, and predisposes the denture to fracture. Provision of adequate denture base material to allow for internal relief results in a disproportionately thickened denture flange, undesirable lip fullness, and distortion of the natural midfacial contours.g An alternative approach would be to shorten the denture flange, precluding extension into alveolar undercuts. Loss of peripheral seal and a weakened denture base become problems with this modification.g The displaceability of the supporting soft tissue permits denture base movement when the prosthesis is subjected to functional and parafunctional occlusal forces. Various fulVOLUME
72
NUMBER
2
Undesirabie diverging tissue undercuts are avoide ~~ote~ti~~y enhanced.
. 5. Abutments
are ideally dome shaped and contoured to ~~~~o~~~a~e~~ 2 mm a&we
crums are developed in the maxillary overdenture relative to abutment location. ~oveme~t toward or away from the residual ridge will occur as rotation about the fulcrum line when the overdenture is occlusally loaded (Fig. 3, A). This tion of the peripheral seal and perception of a loss of retention by the patient (Figs. 3, B and C). The magnitude of a~~ero~osterior rotation can be greatly seduced when fulcrum line passes through incisor teeth. axillary central incisors are ideally located in the arch pport, providing protection to the pre, they have several distinct disadvanhen adjacent abutments are used, the limited ince may make cleaning more difficult for the r&ion, the presence of two adjacent central incisors and their associated alveolar contours can result in an anterior prominence of the overdenture flange comproraising esthetics. Although the anterior location of maxillary central incisors is favorable, their proximity and alveolar prominence may complicate their utilization. Maxillary lateral mcisors offer advantages not realized with the use of the canine or central incisor teeth. Because
i-0 y&Je ‘,f laGer&l i,. of their vocation in the premaxiila, +Lrlv cisors in maintaining the integrity of t&e maxi1ia.q ~.teKiQ~ alveolar ridge is apprecia le. Iu csntrast co maxillary awtrai incisors, lateral incisors are wfdebj separ;j.tedP ~ac~~~~.a~~ ing plaque control. Tissue undercut pmblierms nosmal~y encountered with maxillary canines are waided when maxillary lateral incisors are used (Fig. 4). The alveolar contours of lateral incisors usua$ will not c~~~~~ca~e the path o~~~~ce~e~~ and r~~~~~~ of the ~~~~~~~~~~~ ~~.v~~~~~e esthetic results are readily at”tained, bemuse the bone on the facial aspect of lateral incisors is c~~~~~~~~~~ less prominent than the canine eminences. $3 a rem&, excessive lip support is avoided.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
NELSON
AND
VON
GONTEN
Point Of Rotat ion
Fig.6. Anteroposterior rotation through lateral incisor abutments
of prosthesis is diminished with fulcrum near anterior border of denture.
Stability and retention of the prosthesis are enhanced by the position of maxillary lateral incisors in the arch (Fig. 6). Clinical complaints of a loose maxillary overdenture caused by disruption in the integrity of the peripheral seal are potentially reduced.
SUMMARY The use of maxillary lateral incisors as overdenture abutments provides vertical support to the prosthesis, favorable stress distribution, and preservation of the alveolar bone. in the anterior maxilla. The esthetic result achieved with maxillary overdentures may be enhanced with the use of lateral incisors as abutment teeth. The position and accessibility of maxillary lateral incisors permit the patient to pursue a course of oral hygiene that maintains the supporting periodontium in an optimum state of health. REFERENCES 1. Kelly E. Changes caused by a mandibular removable partial denture opposing a maxillary complete denture. J PROSTHET DENT 1972; 27~140-50. 2. Lord JL, Tee1 S. The overdenture: patient selection, use of copings, and follow-up evaluation. J PROSTHET DENT 1974;32:41-51.
136
line located
3. Landa LS. Diagnosis and management of partially edentulous cases with a minimal number of remaining teeth. Dent Clin North Am 1985;29:3-16. prostheses for edentulous patients 4. Desjardins RP. Tissue-intergrated with normal and abnormal jaw relationships. J PROSTHET DENT 1988;59:180-7. complete 5. Saunders TR, Gillis RE Jr, Desjardins RP. The maxillary denture opposing the mandibular bilateral distal-extension partial denture-treatment considerations. J PROSTHET DENT 197%41:124-g. 6. Brewer AA, Morrow RM. Overdentures. 2nd ed. St Louis: CV Mosby, 1980:3-11. 7. Morrow RM, Brewer AA. Overdentures. 2nd ed. St Louis: CV Mosby, 1980:23-5. 8. Boone ME, Click JP. The use of maxillary centrals and laterals in the overdenture patient. Compendium 1987;8:748-54. 2nd ed. St 9. Winkler S. Essentials of complete denture prosthodontics. Louis: CV Mosby, 1988:384-402. 10. Tallgren A. The continuing reduction of the residual alveolar ridges in complete denture wearers: a mixed-longitudinal study covering 25 years. J PROSTHET DENT 1972;27:120-32. Reprint requests to: DR. DONALD R. NELSON DIVISION OF REMOVABLE PROSTHODONTICS DEPARTMENT OF PROSTHODONTICS COLLEGE OF DENTAL MEDICINE MEDICAL UNIVERSITY OF SOUTH CAROLINA 171 ASHLEY AVE. CHARLESTON, SC 29425
VOLUME
72
NUMBER
2