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An improved component for semifixed bridgework
An improved component for semifixed bridgework
Mervyn C. Lasky, DDS, Hollywood, Calif
A new attachm ent, in which all paralleling is in corporated, has been devised for semifixed bridges. Another innovation, the substitution of cast bands for abutment restorations, makes it unnecessary to cut natural teeth . Appearance, ease of m ain tenance, and the possibility of making alterations when necessary are other advantages of this technic.
An article in t h e j o u r n a l for March 1965 de scribed the semifixed bridge attachments I have been using successfully for more than eight years. Their adaptation to any type of abutment restora tion and their numerous advantages are discussed in the article. One advantage is that the greatest conservation of natural tooth structure and appearance is en sured by the individual preparation and cement ing of abutment restorations. Another advantage is that good hygiene can be maintained with these structures inasmuch as the patient can easily re move and clean them. They can also be added to and altered. Any type of restorative dentistry naturally has limitations. Limitations of semifixed bridges are the extremely short abutments and abutments on which restorations would have little or no reten tion. With these exceptions the attachments are advantageous in all instances where bridges, both fixed and removable, can be constructed. Even if the mucosa over the pontic region is thick, resection of the mucosa can provide sufficient space for the attachments inasmuch as they extend the full occlusogingival length of the pontic. By means of the semifixed bridge technic, the ut most use is made of the abutments and they are conserved. In instances of extreme periodontal involvement, removable pontics with their equal ized broken stress have helped to improve the con dition of the abutments.
FEM ALE
M ALE---
W/
TEN SIO N B A R
m wm m -
---M A L E
OCCLUSAL-ASSEM BLED ATTCH.
IZ J
M ALE M EM BER
T E N S IO N B A R Fig 1
For semifixed attachments, restorations are pre pared individually and cemented without the in fluence of any external force. Consequently they are properly seated and there is far less possibility of recurrent caries. In addition, the patient who has removable pontics can thoroughly cleanse the abutments, thereby reducing the incidence of recurrent caries to a minimum. Should caries re cur, the clinician can readily correct this condi tion because he has easy access to all the teeth when the pontics are removed. This unobstructed access is also an invaluable aid to the operator in performing periodontal treatments and prophy laxes. The success of an operation depends on the conditions present and the ability of the operator. Mistakes in judgment can be made, of course, but the construction of bridges in individual units en ables the operator to make the necessary correc tion of the unit involved. Occasionally, because of initial tension between the abutments when a pontic is first inserted, a restoration may loosen; it can easily be recement ed without disturbing the other restoration. When
loosening occurs because of wear or constant removal and insertion of the pontics, proper ten sion can be restored by adjustment of the tension bars incorporated in each attachment. It is a simple procedure to replace these tension bars should extreme wear occur. Tightening of the bars is rarely necessary more often than once in six months. In a few instances male members have broken. A new restoration has to be made to add a new male member but the remainder of the bridge does not have to be changed. In summary, the bridges are made in individual units and any unit can be repaired or remade without disturbing the others. Also, only one abutment restoration has to be changed if an addition is made to a bridge; the others are left intact. A double female attachment in which all paral leling is incorporated has now been devised. With this attachment no other paralleling is necessary (Fig 1). Another innovation in the use of the attach ments, both the regular and the double, is the substitution of cast bands for abutment restora tions in the usual type of prosthesis. No cutting
Lasky: IMPROVED COMPONENT FOR SEMIFIXED BRIDGEWORK ■ 1147
of natural teeth is required although a minimum of contour reshaping is advantageous for bellcrowned teeth. The cast band procedure is par ticularly indicated for noncarious teeth with no previous restorations. A combination of cast bands and small restorations can also be made. Bands are designed and cast with the use of a surveyor and an opposing model so as to use as much tooth surface as possible. The male members of the at tachments are soldered to the bands. The remain der of the construction is the same as for any semi fixed bridge. Because of the axial inclinations of the natural teeth and the necessity of obtaining the greatest possible coverage of the cast bands, it would be unusual to find an instance in which the two cast bands could be soldered to a pontic; if this were possible, they could not be cemented in position. Patients who have regular semifixed bridges are instructed to remove the pontics once a day and clean them thoroughly. Those who have so-called removable bridges are instructed to remove the
pontics after each meal. It is recommended that dental floss be used under the male members in the mouth to cleanse the small amount of tissue covered. Patients take readily to this routine and have no difficulty removing, cleaning, and rein serting the pontics. Figure 2 shows two nonparalleling, double at tachment bridges. Figure 2A is the buccal view of the male members of a semifixed bridge attach ment replacing a second premolar; inlays were used in the first premolar and first molar. Figure 2B shows the finished bridge. Figure 2C, D, E, F, and G shows a cast band double-attachment restoration of a first molar. Figure 2C is the study model. Figures 2D and E are buccal and occlusal views of placement of the attachments. Figure 2F shows the male members soldered to the bands; these male members are not soldered together— they merely abut each other. Figure 2G is the completed bridge. Figure 3 shows a single-attachment restoration of a first premolar. A cast band was used on the
Fig 4 Lasky: IMPROVED COMPONENT FOR SEMIFIXED BRIDGEWORK ■ 1149
Fig 5
Fig 6
second premolar and a proximolingual rest was used on the canine. Figure 3A shows the male member soldered to the cast band. Figures 3B and C are the buccal and lingual views of the occlusal casting before the acrylic facings were added. Figure 3D shows the completed bridge on the model and Figure 3E shows the bridge in the pa tient’s mouth. Figure 4 shows another single-attachment resto ration of the right central incisor. A porcelain jacket was used on the left central incisor and a proximolingual rest on the right lateral incisor. Figures 4A and B are the labial and palatal views; Figure 4C shows the finished bridge. Figure 5 shows a distal extension single-attach ment restoration of a first molar. A porcelain jack et was used on the second premolar and a mesio1150 ■ JADA, Vol. 79, November 1969
distal grip clasp was used on the canine. Figure 6 shows how additions can be made. The right and left upper and the left lower semi fixed bridges had been constructed previously. The upper left central incisor was unsuccessfully treated endodontically and had to be removed. A palatal casting supporting this tooth was connected to the two upper bridges. Figures 6A and B show the right side and Figures C and D the left side of the previously constructed bridges; the left upper is a one-attachment bridge. Figure 6E shows the palatal casting and Figure 6F is the labial view of the completed work.
Doctor Lasky’s address is 1535 N Poinsettia PI, H o lly wood, C alif 90046.
Mervyn C. Lasky, DDS, Hollywood, Calif
A new attachm ent, in which all paralleling is in corporated, has been devised for semifixed bridges. Another innovation, the substitution of cast bands for abutment restorations, makes it unnecessary to cut natural teeth . Appearance, ease of m ain tenance, and the possibility of making alterations when necessary are other advantages of this technic.
An article in t h e j o u r n a l for March 1965 de scribed the semifixed bridge attachments I have been using successfully for more than eight years. Their adaptation to any type of abutment restora tion and their numerous advantages are discussed in the article. One advantage is that the greatest conservation of natural tooth structure and appearance is en sured by the individual preparation and cement ing of abutment restorations. Another advantage is that good hygiene can be maintained with these structures inasmuch as the patient can easily re move and clean them. They can also be added to and altered. Any type of restorative dentistry naturally has limitations. Limitations of semifixed bridges are the extremely short abutments and abutments on which restorations would have little or no reten tion. With these exceptions the attachments are advantageous in all instances where bridges, both fixed and removable, can be constructed. Even if the mucosa over the pontic region is thick, resection of the mucosa can provide sufficient space for the attachments inasmuch as they extend the full occlusogingival length of the pontic. By means of the semifixed bridge technic, the ut most use is made of the abutments and they are conserved. In instances of extreme periodontal involvement, removable pontics with their equal ized broken stress have helped to improve the con dition of the abutments.
FEM ALE
M ALE---
W/
TEN SIO N B A R
m wm m -
---M A L E
OCCLUSAL-ASSEM BLED ATTCH.
IZ J
M ALE M EM BER
T E N S IO N B A R Fig 1
For semifixed attachments, restorations are pre pared individually and cemented without the in fluence of any external force. Consequently they are properly seated and there is far less possibility of recurrent caries. In addition, the patient who has removable pontics can thoroughly cleanse the abutments, thereby reducing the incidence of recurrent caries to a minimum. Should caries re cur, the clinician can readily correct this condi tion because he has easy access to all the teeth when the pontics are removed. This unobstructed access is also an invaluable aid to the operator in performing periodontal treatments and prophy laxes. The success of an operation depends on the conditions present and the ability of the operator. Mistakes in judgment can be made, of course, but the construction of bridges in individual units en ables the operator to make the necessary correc tion of the unit involved. Occasionally, because of initial tension between the abutments when a pontic is first inserted, a restoration may loosen; it can easily be recement ed without disturbing the other restoration. When
loosening occurs because of wear or constant removal and insertion of the pontics, proper ten sion can be restored by adjustment of the tension bars incorporated in each attachment. It is a simple procedure to replace these tension bars should extreme wear occur. Tightening of the bars is rarely necessary more often than once in six months. In a few instances male members have broken. A new restoration has to be made to add a new male member but the remainder of the bridge does not have to be changed. In summary, the bridges are made in individual units and any unit can be repaired or remade without disturbing the others. Also, only one abutment restoration has to be changed if an addition is made to a bridge; the others are left intact. A double female attachment in which all paral leling is incorporated has now been devised. With this attachment no other paralleling is necessary (Fig 1). Another innovation in the use of the attach ments, both the regular and the double, is the substitution of cast bands for abutment restora tions in the usual type of prosthesis. No cutting
Lasky: IMPROVED COMPONENT FOR SEMIFIXED BRIDGEWORK ■ 1147
of natural teeth is required although a minimum of contour reshaping is advantageous for bellcrowned teeth. The cast band procedure is par ticularly indicated for noncarious teeth with no previous restorations. A combination of cast bands and small restorations can also be made. Bands are designed and cast with the use of a surveyor and an opposing model so as to use as much tooth surface as possible. The male members of the at tachments are soldered to the bands. The remain der of the construction is the same as for any semi fixed bridge. Because of the axial inclinations of the natural teeth and the necessity of obtaining the greatest possible coverage of the cast bands, it would be unusual to find an instance in which the two cast bands could be soldered to a pontic; if this were possible, they could not be cemented in position. Patients who have regular semifixed bridges are instructed to remove the pontics once a day and clean them thoroughly. Those who have so-called removable bridges are instructed to remove the
pontics after each meal. It is recommended that dental floss be used under the male members in the mouth to cleanse the small amount of tissue covered. Patients take readily to this routine and have no difficulty removing, cleaning, and rein serting the pontics. Figure 2 shows two nonparalleling, double at tachment bridges. Figure 2A is the buccal view of the male members of a semifixed bridge attach ment replacing a second premolar; inlays were used in the first premolar and first molar. Figure 2B shows the finished bridge. Figure 2C, D, E, F, and G shows a cast band double-attachment restoration of a first molar. Figure 2C is the study model. Figures 2D and E are buccal and occlusal views of placement of the attachments. Figure 2F shows the male members soldered to the bands; these male members are not soldered together— they merely abut each other. Figure 2G is the completed bridge. Figure 3 shows a single-attachment restoration of a first premolar. A cast band was used on the
Fig 4 Lasky: IMPROVED COMPONENT FOR SEMIFIXED BRIDGEWORK ■ 1149
Fig 5
Fig 6
second premolar and a proximolingual rest was used on the canine. Figure 3A shows the male member soldered to the cast band. Figures 3B and C are the buccal and lingual views of the occlusal casting before the acrylic facings were added. Figure 3D shows the completed bridge on the model and Figure 3E shows the bridge in the pa tient’s mouth. Figure 4 shows another single-attachment resto ration of the right central incisor. A porcelain jacket was used on the left central incisor and a proximolingual rest on the right lateral incisor. Figures 4A and B are the labial and palatal views; Figure 4C shows the finished bridge. Figure 5 shows a distal extension single-attach ment restoration of a first molar. A porcelain jack et was used on the second premolar and a mesio1150 ■ JADA, Vol. 79, November 1969
distal grip clasp was used on the canine. Figure 6 shows how additions can be made. The right and left upper and the left lower semi fixed bridges had been constructed previously. The upper left central incisor was unsuccessfully treated endodontically and had to be removed. A palatal casting supporting this tooth was connected to the two upper bridges. Figures 6A and B show the right side and Figures C and D the left side of the previously constructed bridges; the left upper is a one-attachment bridge. Figure 6E shows the palatal casting and Figure 6F is the labial view of the completed work.
Doctor Lasky’s address is 1535 N Poinsettia PI, H o lly wood, C alif 90046.