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Ramus Endosseous Frame Implant for Use with Patient’s Denture: Report of Case
Ram us endosseous fram e im plant for use with patient’s denture: report of case
D onald L. Cram, DDS, Loma Linda, C a lif H arold Roberts, DMD, Vancouver, B ritish C olum bia Lloyd Baum, DMD, Loma Linda, C a lif
A one-piece endosseous im p la n t was designed fo r use in th e m an d ib le . The posterior p o rtio n o f th e im p la n t is lodged between th e buccal and lingu al plates o f co rtica l bone. The a n te rio r p o r tio n , w hich can be adjusted, is fitte d in to th e sym physis region. W ith use o f an a crylic resin, th e p a tie n t’s denture can be m olded to th e shape o f the su perstructure o f th e im p la n t. Advantages o f the im p la n t in clu d e one tre a tm e n t v is it, decreased
formance and high success rate (91 % to 9 4% ) over five years or longer has proved its value.1 For the general public, however, use of the full subperiosteal implant has some drawbacks. The surgical procedures usually require two appoint ments, and the patient is subjected to considerable trauma. The skill and training for the successful performance o f the surgery is not likely to be m as tered by the general practitioner. Despite these two objections, the greatest single drawback is economics. Laboratory and attendant fees re quired for the successful placement o f the sub periosteal implant, its superstructure, and den ture make it prohibitive as a service to the average edentulous person.
surgical tim e, reduced cost, and decreased pa tie n t discom fort.
Often, the patient is unable to wear a mandibular denture appliance successfully. The dentist knows that this is logical because of resorption and atrophy o f the bone with an active peripheral musculature surrounding the lower denture. The patient who wears an unsatisfactory denture may well experience frustration, discomfort, and in convenience. Dentistry has provided some of these patients with a solution to their problem in the form of the full subperiosteal implant (Fig 1). Its per 156 ■ JADA, Vol. 84, January 1972
Fig 1 ■ M andibular subperiosteal im p la nt fram ework on study cast.
Endosseous implants also have been used in one form or another, with the metal being an chored inside rather than outside the bone. D e signs o f endosseous implants include screws, pins, and blades o f various configurations.2 The ramus blade implant3 differs essentially only in its site of placement. Rather than being placed downward into the alveolar bone of the mandible, the ramus implant is thrust posteriorly into the ramus where it is lodged between the buccal and lingual plates of cortical bone. A one-piece endosseous implant (Fig 2) was designed for use with the two rami and the sym physis o f the mandible as support. In these three places, the bone is dense and relatively free of neurologic and vascular tissues. The implant is fabricated, 2 mm thick, o f wrought ASTM-F-56 orthopedic metal.4 The metal is soft enough to be bent with pliers to conform to individual m an dibular characteristics. Examination of a large variety of edentulous mandibles (dry specimens) has revealed a sur prising fact. Except for minor variations, all m an dibles have similar dimensions (Fig 3). The dis tance in width between the coronoid notches (the depth of the notch o f the anterior border of the ramus of the mandible) is 83 ± 3 mm, whereas the distance between one coronoid notch and the symphysis is 64 ± 4 mm. This means that a p re formed implant that would fit the rami of a square, wide mandible also could be bent to fit a narrow, long one. A differential in circumfer ential measurement of these three points can be offset in the symphysis where the bone is wide between the genial tubercles and the labial side.
Fig 2 ■ Ramus endosseous frame im plant.
Fig 3 ■ Measurements taken for ramus endosseous fram e im plant.
Two sizes of prefabricated implants have been found that will adequately cover the variety of situations.
Surgical technique After bilateral local anesthesia has been admin istered, the two vertical incisions are made buccal to the right and left retromolar pads. After the tissue has been reflected, the bone is cut with a 560 bur to form two slots o f proper width, length, and depth to receive the two distal extensions of the implant (Fig 4). C are is exercised to keep the cuts parallel to each other in a vertical plane and to make them diverge slightly toward the dis tal aspect so the rami will be properly engaged. After these two slots have been made, right and left distal segments o f the implant are tried in the spaces to ensure proper alignment and position. The complete frame then is taken to the mouth and the two posterior extensions of the implant are inserted into the bone. As the anterior “T ” p o r tion is brought down to touch the ridge in the symphysis region, the site of entry is marked for the third tissue incision. After reflection o f the tissue and adequate ex posure of the bone, a 560 bur is used in the air rotor handpiece to mortise a curved slot approxi mately 30 mm long and 8 mm deep (Fig 5). The Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 157
Fig 4 ■ Left: Try-in o f rig ht segment o f ram us fram e im p la nt on dry specimen. Right: Try-in o f rig h t segment o f ramus fram e im p la nt in a patient.
Fig 5 ■ Osseous groove c u t in symphysis region to accom m odate th e anterior s tru t o f th e im plant.
anterior portion o f the frame is tried in position; the posterior ends serve as pivot points within their respective slots. At this point in the fitting, it may be necessary for the anterior portion to be bent labially or lingually to match the anterior slot (Fig 6). When the fitting has been completed, the tis sue flaps are repositioned and sutures are placed mesial and distal to the anterior connector and the posterior extensions. Cleansing and debridement of the oral cavity is now done in preparation for the fitting of the denture. 158 ■ JADA, Vol. 84, January 1972
Fig 6 ■ Illu stra tio n o f bending o f anterior stru t to match groove in symphysis region.
Prosthetic procedure A deep vertical groove is made in the patient’s denture to receive the bar of the implant (Fig 7). The denture is fitted in position by trial and error and tested for vertical dimension and for occlu sion. Acrylic buccal and lingual flanges that ex
Fig 7 ■ Denture is prepared w ith a deep vertical groove inside.
tend below the lower edge of the frame are re duced in length. Acrylic resin now is added into the recessed area. When the acrylic resin is at the heavy, doughy stage, the denture is placed in the mouth and seated in occlusion. So that the acrylic resin is molded satisfactorily to the frame, a celluloid strip may be inserted underneath the denture and pulled upward to compress the material and force it against the sides o f the bar. During the rubbery
stage o f set, the denture is removed and placed in hot water to complete polymerization. Buccal and lingual flanges again are reduced in length and constricted toward the bar (Fig 8). Minor adjust ments are made to enable the patient to remove and replace the denture with ease. After conventional polishing procedures are completed, the denture is placed and the patient is dismissed. Routine postoperative care is con ducted in harmony with the oral surgical p ro
Fig 8 ■ Buccal and lingual flanges o f denture reduced in length and co n stricte d toward bar. Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 159
cedures. Use of the appliance can begin immed iately, tissue soreness notwithstanding.
Report of case The patient was a 52-year-old, white woman who was slender, and apparently healthy. She had several consultations with her dentist concerning the fabrication of a new lower denture as she was unable to wear her existing one. In a clinical examination of the patient’s mouth, oral mucosa over a minimal mandibular alveolar ridge ap peared to be healthy. A panoramic radiograph (Fig 9) disclosed a small resorbed alveolus and body of the mandible. It was thought that most conventional types of preprosthetic surgery would produce no significant clinical improvement. After evaluation o f the patient’s medical his tory, we thought that she would be a suitable can didate for the endosseous ramus frame implant. Careful measurements were taken to determine the intercoronoid notch distance and the distance between the coronoid notch and symphysis. The intercoronoid notch distance was 83 mm and the distance o f the coronoid notch to symphysis was 60 mm, 4 mm below the average value. Administration of intravenous sedation5 was followed by bilateral local anesthesia with 2% mepivacaine (Carbocaine) hydrochloride and vasoconstrictor. A 1.5 cm incision was made in the right retromolar region just lateral to the retromolar pad and medial to the depth of the coronoid notch. The mandible was exposed af ter reflection of the mucoperiosteal flap. Medial palpation of the ramus disclosed the position of the lingula and the depth of the inferior alveolar neurovascular bundle was identified. A 560 bur
in a straight handpiece (Hall Surgitome) was used to make a vertical, 1 cm groove in the bone. The posterior portion of the implant then was placed in the groove. The distal end fitted well into the slot but projected upward at an angle. In order for the implant to engage the bone and yet remain parallel to the body of the mandible, it was neces sary to reshape the slot from that of a parallelo gram with right angles to one with acute and ob tuse angles. By alternate fitting and routing of the bone, this was accomplished. A similar incision was made on the left ramus of the mandible, the mandible was prepared, and the complete ramus implant was tried in place. With the posterior ends in pivot position, the implant was rotated downward to mark the an terior incision line. Additional local anesthetic was infiltrated in the region for hemostasis and a 3 to 4 cm incision was made. After the tissue was reflected, a contra-angle handpiece was attached to the Surgitome, and a 560 bur was used to make the curved vertical groove approximately 8 mm deep and 30 mm in length in the symphysis re gion. Fitting of the anterior strut was the most difficult part o f the procedure. After the final fit, the anterior support was malleted firmly to place. A slight crimp in the end of the anterior support provided a positive wedg ing action and thereby restricted dislodgement or any movement of the implant. Two simple no. 3-0 silk sutures, were placed bilaterally and pos teriorly to close the mucoperiosteum. A continu ous locked suture was made in the anterior region to close the symphysis incision and a purse-string suture was placed around the verticle support. Approximately two hours were involved in the surgical phase of the procedure. Blood loss was minimal, the patient reported no appreciable dis-
Fig 9 ■ Radiograph o f resorbed m andible. 160 ■ JADA, Vol. 84, January 1972
Fig 10 ■ Postoperative radiograph o f patient w ith dentures in place.
Fig 11 ■ Photographs o f im plant in place three m onths after surgery.
Fig 12 ■ Dentures in place over endosseous fram e ramus im plant.
comfort during the procedure. At this point, the patient’s lower denture was prepared and placed on the superstructure. V er tical and centric measurements were approxim ate ly established. The denture was adapted to the vertical bar as in the prosthetic procedure which has been outlined. After the maxillary denture
was in place, occlusion was tested. Carbon paper markings showed occlusal interferences which were easily reduced by conventional procedures. A postoperative panoramic radiograph was taken with the dentures in place (Fig 10). The patient was dismissed with a prescription for erythromycin 250 mg and Phenaphen with Vi grain codeine. Sutures were removed in one week at which time the patient reported that she had taken three of the prescribed pain capsules, but that thereafter, aspirin was adequate for pain control. Three months after surgery, the tissue sur rounding the implant appeared healthy and the implant was stable (Fig 11). Although m astica tory function was adequate with the old denture (Fig 12), new dentures will be made in a few months.
Comments In view o f the simplicity o f the operation and the utilization of the existing lower denture, this form of treatment does show considerable promise. Sur Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 161
gical time could be decreased to about one hour as the clinician becomes increasingly familiar with the procedure. Patient discomfort might be com parable to that of having had one or two impact ed teeth removed. To date, 12 of these implants have been placed and observed for periods o f up to eight months. Tissue response is quite encouraging. The economic advantages to the patient are obvious. The surgical procedure, followed by the prosthetic application, provides an excellent team approach that can be used by the oral surgeon and the general practitioner in the treatment of edentulous patients. Guarded speculation on the success of the sub periosteal implant is encouraged by previous ex perience with blade implants.2’6-7 Where the site of entry is in the region of the retromolar pad at the border of attached gingiva, continuous flex ing of the tissue may contribute to early rejection of the implant. Because o f the minimal trauma, expense, and effort involved, the patient who would keep the implant for only two or three years would realize substantial benefit. Observations o f tissue reac
162 ■ JADA, Vol. 84, January 1972
tion, rejection patterns, and so forth are im por tant considerations in the appraisal of this tech nique in prosthodontic therapy.
D o c to r C ra m is a s s is ta n t p ro fe s s o r in th e o ra l s u rg e ry d e p a r tm e n t, a n d D o c to r B aum is p ro fe s s o r o f re s to ra tiv e d e n tis tr y , L o m a L in d a U n iv e rs ity S ch ool o f D e n tis try , Lom a L in d a , C a lif 9 2 3 5 4 . D o c to r R o b e rts ’ a d d re s s is 1 8 6 2 W B ro ad w a y , V a n c o u v e r, B ritis h C o lu m b ia .
1. Y u rk s ta s , A .A . T h e c u r re n t s ta tu s o f im p la n ts in p rosth o d o n tic s . N e w s le tt A m e r A c a d Im p la n t D e n t 1 6 :1 A pril 1967. 2. C ra n in , A ., ed. O ral im p la n to lo g y , S p rin g fie ld , III, C h a rle s C T h o m a s , 1 9 7 0 . 3. R o b e rts , H .D ., a n d R o b e rts , R .A . T h e ra m u s e n d o s s e o u s im p la n t. J S C a lif D e n t Assn 3 8 :5 7 1 J u ly 1 9 7 0 . 4 . M e ta ls fo r im p la n ta tio n in th e h u m a n body. In Ann N Y A c a d S ci 1 4 6 :8 0 Jan 8, 1 9 6 8 . 5. Jo rg e n s en , N .B ., a n d H a y d e n , J., Jr. P re m e d ic a tio n , lo cal a n d g e n e ra l a n e s th e s ia in d e n tis try . P h ila d e lp h ia , L e a & F e b ig e r, 1 9 6 7 . 6. Lew , I. T h e e n d o s s e o u s im p la n t; e v a lu a tio n s a n d m o d ific a tio n s . D e n t C lin o f N A m e r 1 4 :2 0 1 Jan 1 9 7 0 . 7. L in k o w , L .l. E ndosseous o ral im p la n to lo g y : a 7 -y e a r p ro g re s s rep o rt. D e n t C lin o f N A m e r 1 4 :1 8 5 Jan 1 9 7 0 .
D onald L. Cram, DDS, Loma Linda, C a lif H arold Roberts, DMD, Vancouver, B ritish C olum bia Lloyd Baum, DMD, Loma Linda, C a lif
A one-piece endosseous im p la n t was designed fo r use in th e m an d ib le . The posterior p o rtio n o f th e im p la n t is lodged between th e buccal and lingu al plates o f co rtica l bone. The a n te rio r p o r tio n , w hich can be adjusted, is fitte d in to th e sym physis region. W ith use o f an a crylic resin, th e p a tie n t’s denture can be m olded to th e shape o f the su perstructure o f th e im p la n t. Advantages o f the im p la n t in clu d e one tre a tm e n t v is it, decreased
formance and high success rate (91 % to 9 4% ) over five years or longer has proved its value.1 For the general public, however, use of the full subperiosteal implant has some drawbacks. The surgical procedures usually require two appoint ments, and the patient is subjected to considerable trauma. The skill and training for the successful performance o f the surgery is not likely to be m as tered by the general practitioner. Despite these two objections, the greatest single drawback is economics. Laboratory and attendant fees re quired for the successful placement o f the sub periosteal implant, its superstructure, and den ture make it prohibitive as a service to the average edentulous person.
surgical tim e, reduced cost, and decreased pa tie n t discom fort.
Often, the patient is unable to wear a mandibular denture appliance successfully. The dentist knows that this is logical because of resorption and atrophy o f the bone with an active peripheral musculature surrounding the lower denture. The patient who wears an unsatisfactory denture may well experience frustration, discomfort, and in convenience. Dentistry has provided some of these patients with a solution to their problem in the form of the full subperiosteal implant (Fig 1). Its per 156 ■ JADA, Vol. 84, January 1972
Fig 1 ■ M andibular subperiosteal im p la nt fram ework on study cast.
Endosseous implants also have been used in one form or another, with the metal being an chored inside rather than outside the bone. D e signs o f endosseous implants include screws, pins, and blades o f various configurations.2 The ramus blade implant3 differs essentially only in its site of placement. Rather than being placed downward into the alveolar bone of the mandible, the ramus implant is thrust posteriorly into the ramus where it is lodged between the buccal and lingual plates of cortical bone. A one-piece endosseous implant (Fig 2) was designed for use with the two rami and the sym physis o f the mandible as support. In these three places, the bone is dense and relatively free of neurologic and vascular tissues. The implant is fabricated, 2 mm thick, o f wrought ASTM-F-56 orthopedic metal.4 The metal is soft enough to be bent with pliers to conform to individual m an dibular characteristics. Examination of a large variety of edentulous mandibles (dry specimens) has revealed a sur prising fact. Except for minor variations, all m an dibles have similar dimensions (Fig 3). The dis tance in width between the coronoid notches (the depth of the notch o f the anterior border of the ramus of the mandible) is 83 ± 3 mm, whereas the distance between one coronoid notch and the symphysis is 64 ± 4 mm. This means that a p re formed implant that would fit the rami of a square, wide mandible also could be bent to fit a narrow, long one. A differential in circumfer ential measurement of these three points can be offset in the symphysis where the bone is wide between the genial tubercles and the labial side.
Fig 2 ■ Ramus endosseous frame im plant.
Fig 3 ■ Measurements taken for ramus endosseous fram e im plant.
Two sizes of prefabricated implants have been found that will adequately cover the variety of situations.
Surgical technique After bilateral local anesthesia has been admin istered, the two vertical incisions are made buccal to the right and left retromolar pads. After the tissue has been reflected, the bone is cut with a 560 bur to form two slots o f proper width, length, and depth to receive the two distal extensions of the implant (Fig 4). C are is exercised to keep the cuts parallel to each other in a vertical plane and to make them diverge slightly toward the dis tal aspect so the rami will be properly engaged. After these two slots have been made, right and left distal segments o f the implant are tried in the spaces to ensure proper alignment and position. The complete frame then is taken to the mouth and the two posterior extensions of the implant are inserted into the bone. As the anterior “T ” p o r tion is brought down to touch the ridge in the symphysis region, the site of entry is marked for the third tissue incision. After reflection o f the tissue and adequate ex posure of the bone, a 560 bur is used in the air rotor handpiece to mortise a curved slot approxi mately 30 mm long and 8 mm deep (Fig 5). The Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 157
Fig 4 ■ Left: Try-in o f rig ht segment o f ram us fram e im p la nt on dry specimen. Right: Try-in o f rig h t segment o f ramus fram e im p la nt in a patient.
Fig 5 ■ Osseous groove c u t in symphysis region to accom m odate th e anterior s tru t o f th e im plant.
anterior portion o f the frame is tried in position; the posterior ends serve as pivot points within their respective slots. At this point in the fitting, it may be necessary for the anterior portion to be bent labially or lingually to match the anterior slot (Fig 6). When the fitting has been completed, the tis sue flaps are repositioned and sutures are placed mesial and distal to the anterior connector and the posterior extensions. Cleansing and debridement of the oral cavity is now done in preparation for the fitting of the denture. 158 ■ JADA, Vol. 84, January 1972
Fig 6 ■ Illu stra tio n o f bending o f anterior stru t to match groove in symphysis region.
Prosthetic procedure A deep vertical groove is made in the patient’s denture to receive the bar of the implant (Fig 7). The denture is fitted in position by trial and error and tested for vertical dimension and for occlu sion. Acrylic buccal and lingual flanges that ex
Fig 7 ■ Denture is prepared w ith a deep vertical groove inside.
tend below the lower edge of the frame are re duced in length. Acrylic resin now is added into the recessed area. When the acrylic resin is at the heavy, doughy stage, the denture is placed in the mouth and seated in occlusion. So that the acrylic resin is molded satisfactorily to the frame, a celluloid strip may be inserted underneath the denture and pulled upward to compress the material and force it against the sides o f the bar. During the rubbery
stage o f set, the denture is removed and placed in hot water to complete polymerization. Buccal and lingual flanges again are reduced in length and constricted toward the bar (Fig 8). Minor adjust ments are made to enable the patient to remove and replace the denture with ease. After conventional polishing procedures are completed, the denture is placed and the patient is dismissed. Routine postoperative care is con ducted in harmony with the oral surgical p ro
Fig 8 ■ Buccal and lingual flanges o f denture reduced in length and co n stricte d toward bar. Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 159
cedures. Use of the appliance can begin immed iately, tissue soreness notwithstanding.
Report of case The patient was a 52-year-old, white woman who was slender, and apparently healthy. She had several consultations with her dentist concerning the fabrication of a new lower denture as she was unable to wear her existing one. In a clinical examination of the patient’s mouth, oral mucosa over a minimal mandibular alveolar ridge ap peared to be healthy. A panoramic radiograph (Fig 9) disclosed a small resorbed alveolus and body of the mandible. It was thought that most conventional types of preprosthetic surgery would produce no significant clinical improvement. After evaluation o f the patient’s medical his tory, we thought that she would be a suitable can didate for the endosseous ramus frame implant. Careful measurements were taken to determine the intercoronoid notch distance and the distance between the coronoid notch and symphysis. The intercoronoid notch distance was 83 mm and the distance o f the coronoid notch to symphysis was 60 mm, 4 mm below the average value. Administration of intravenous sedation5 was followed by bilateral local anesthesia with 2% mepivacaine (Carbocaine) hydrochloride and vasoconstrictor. A 1.5 cm incision was made in the right retromolar region just lateral to the retromolar pad and medial to the depth of the coronoid notch. The mandible was exposed af ter reflection of the mucoperiosteal flap. Medial palpation of the ramus disclosed the position of the lingula and the depth of the inferior alveolar neurovascular bundle was identified. A 560 bur
in a straight handpiece (Hall Surgitome) was used to make a vertical, 1 cm groove in the bone. The posterior portion of the implant then was placed in the groove. The distal end fitted well into the slot but projected upward at an angle. In order for the implant to engage the bone and yet remain parallel to the body of the mandible, it was neces sary to reshape the slot from that of a parallelo gram with right angles to one with acute and ob tuse angles. By alternate fitting and routing of the bone, this was accomplished. A similar incision was made on the left ramus of the mandible, the mandible was prepared, and the complete ramus implant was tried in place. With the posterior ends in pivot position, the implant was rotated downward to mark the an terior incision line. Additional local anesthetic was infiltrated in the region for hemostasis and a 3 to 4 cm incision was made. After the tissue was reflected, a contra-angle handpiece was attached to the Surgitome, and a 560 bur was used to make the curved vertical groove approximately 8 mm deep and 30 mm in length in the symphysis re gion. Fitting of the anterior strut was the most difficult part o f the procedure. After the final fit, the anterior support was malleted firmly to place. A slight crimp in the end of the anterior support provided a positive wedg ing action and thereby restricted dislodgement or any movement of the implant. Two simple no. 3-0 silk sutures, were placed bilaterally and pos teriorly to close the mucoperiosteum. A continu ous locked suture was made in the anterior region to close the symphysis incision and a purse-string suture was placed around the verticle support. Approximately two hours were involved in the surgical phase of the procedure. Blood loss was minimal, the patient reported no appreciable dis-
Fig 9 ■ Radiograph o f resorbed m andible. 160 ■ JADA, Vol. 84, January 1972
Fig 10 ■ Postoperative radiograph o f patient w ith dentures in place.
Fig 11 ■ Photographs o f im plant in place three m onths after surgery.
Fig 12 ■ Dentures in place over endosseous fram e ramus im plant.
comfort during the procedure. At this point, the patient’s lower denture was prepared and placed on the superstructure. V er tical and centric measurements were approxim ate ly established. The denture was adapted to the vertical bar as in the prosthetic procedure which has been outlined. After the maxillary denture
was in place, occlusion was tested. Carbon paper markings showed occlusal interferences which were easily reduced by conventional procedures. A postoperative panoramic radiograph was taken with the dentures in place (Fig 10). The patient was dismissed with a prescription for erythromycin 250 mg and Phenaphen with Vi grain codeine. Sutures were removed in one week at which time the patient reported that she had taken three of the prescribed pain capsules, but that thereafter, aspirin was adequate for pain control. Three months after surgery, the tissue sur rounding the implant appeared healthy and the implant was stable (Fig 11). Although m astica tory function was adequate with the old denture (Fig 12), new dentures will be made in a few months.
Comments In view o f the simplicity o f the operation and the utilization of the existing lower denture, this form of treatment does show considerable promise. Sur Cram—Roberts—Baum: RAMUS ENDOSSEOUS IMPLANT ■ 161
gical time could be decreased to about one hour as the clinician becomes increasingly familiar with the procedure. Patient discomfort might be com parable to that of having had one or two impact ed teeth removed. To date, 12 of these implants have been placed and observed for periods o f up to eight months. Tissue response is quite encouraging. The economic advantages to the patient are obvious. The surgical procedure, followed by the prosthetic application, provides an excellent team approach that can be used by the oral surgeon and the general practitioner in the treatment of edentulous patients. Guarded speculation on the success of the sub periosteal implant is encouraged by previous ex perience with blade implants.2’6-7 Where the site of entry is in the region of the retromolar pad at the border of attached gingiva, continuous flex ing of the tissue may contribute to early rejection of the implant. Because o f the minimal trauma, expense, and effort involved, the patient who would keep the implant for only two or three years would realize substantial benefit. Observations o f tissue reac
162 ■ JADA, Vol. 84, January 1972
tion, rejection patterns, and so forth are im por tant considerations in the appraisal of this tech nique in prosthodontic therapy.
D o c to r C ra m is a s s is ta n t p ro fe s s o r in th e o ra l s u rg e ry d e p a r tm e n t, a n d D o c to r B aum is p ro fe s s o r o f re s to ra tiv e d e n tis tr y , L o m a L in d a U n iv e rs ity S ch ool o f D e n tis try , Lom a L in d a , C a lif 9 2 3 5 4 . D o c to r R o b e rts ’ a d d re s s is 1 8 6 2 W B ro ad w a y , V a n c o u v e r, B ritis h C o lu m b ia .
1. Y u rk s ta s , A .A . T h e c u r re n t s ta tu s o f im p la n ts in p rosth o d o n tic s . N e w s le tt A m e r A c a d Im p la n t D e n t 1 6 :1 A pril 1967. 2. C ra n in , A ., ed. O ral im p la n to lo g y , S p rin g fie ld , III, C h a rle s C T h o m a s , 1 9 7 0 . 3. R o b e rts , H .D ., a n d R o b e rts , R .A . T h e ra m u s e n d o s s e o u s im p la n t. J S C a lif D e n t Assn 3 8 :5 7 1 J u ly 1 9 7 0 . 4 . M e ta ls fo r im p la n ta tio n in th e h u m a n body. In Ann N Y A c a d S ci 1 4 6 :8 0 Jan 8, 1 9 6 8 . 5. Jo rg e n s en , N .B ., a n d H a y d e n , J., Jr. P re m e d ic a tio n , lo cal a n d g e n e ra l a n e s th e s ia in d e n tis try . P h ila d e lp h ia , L e a & F e b ig e r, 1 9 6 7 . 6. Lew , I. T h e e n d o s s e o u s im p la n t; e v a lu a tio n s a n d m o d ific a tio n s . D e n t C lin o f N A m e r 1 4 :2 0 1 Jan 1 9 7 0 . 7. L in k o w , L .l. E ndosseous o ral im p la n to lo g y : a 7 -y e a r p ro g re s s rep o rt. D e n t C lin o f N A m e r 1 4 :1 8 5 Jan 1 9 7 0 .