Recent developments in interpositional bone-grafting of the atrophic mandible

14

J. max.-fac. Surg. 13 (1985)

J. max.-fac. Surg. 13 (1985) 14-23 © Georg Thieme Verlag Stuttgart . New York

Recent Developments in Interpositional BoneGrafting of the Atrophic Mandible Frank Moloney, PauI J. W. Stoelinga, Henk Tideman, Hans A. de Koomen Department of Oral and Maxillofacial Surgery and Prosthodontics, Municipal Hospital, Arnhem, The Netherlands

Submitted for publication 18.1. 1984 Accepted 17. 2. 1984

Introduction In recent years the interposed bone-graft technique has provided the oral and maxillofacial surgeon with an unique method of rebuilding the atrophic mandibular ridge. Follow-up studies (de Koomen et al., 1979; H~irle, 1979; Fitzpatrick, 1981; Frost et al., 1982; Stoelinga et al., 1983) have shown steady improvements in results which continue to justify the use of this reconstructive surgical approach. It had generally been accepted that a routine vestibuloplasty was a necessary sequel to ridge augmentation irrespective of the bone-grafting technique employed. The shape and form of the vestibule was disturbed for several reasons after the first operation. These included such factors as design of the incision and healing of the elevated flaps in the anterior region. An earlier report (Stoelinga et al., 1983) contained evidence that 13 % less resorption in the anterior region could be expected after 24 months, if follow-up vestibuloplasty was deliberately avoided. This second operation was also found to contribute to about 25 % of the long-term nerve disturbance pattern (de Koomen, 1982). As sensibility problems would seem to represent the major unwanted side-effect of this approach to ridge augmentation, elimination of the vestibuloplasty could bring about a significant improvement in results. It had been the clinical impression of the senior authors (P. S., H. T., H. d. K.) that the anterior resorption pattern was similar in dimension to that occurring in the body region bilaterally. A standardized method of assessing anterior resorption from lateral cephalographs was reported by de Koomen et al. (1979), and found application in a recent study by Sugar and Hopkins (1982). Assessment of resorption posterior to the mental foramen has remained a difficult issue, measurement from panoramic radiographs being difficult to standardize. The studies by Fazili et al. (1978) and van Waas (1979) suggested, however, that acceptable results could be achieved if an average height was calculated from six reference points behind the mental foramen. A modification of this technique was used in this study.

Summary A clinical study on 54 patients, who underwent augmentation of the atrophic mandible by interposed bone-grafts, but in whom routine follow-up vestibuloplasty was deliberately avoided, is presented. The results show a reduced rate of bone resorption in the anterior region and less interference with lip and chin sensibility. An additional study is included concerning the fate of the elevated ridge and associated bone-graft in the body region posterior to the mental foramen. Results suggest that the resorption pattern in this area is very similar to that of a subperiosteal bone-graft. Modification of surgical technique in this regard has produced encouraging results.

Key-Words Atrophy - Mandibular ridge augmentation - Interposed bone-graft - Vestibuloplasty

It was therefore the dual aim of this investigation: 1. to study the effects of a treatment protocol which deliberately avoided follow-up vestibuloplasty, and 2. to study the fate of the bone-graft and raised alveolar ridge in the body region to provide statistics for a future comparison of the standard "one piece" and the "three piece" augmentation technique as described by Stoelinga et al. (1983).

Historical Aspects The long-term results of subperiosteal bone-grafting techniques have generally been very disappointing. Resorption rates from 60-90 % have been common (Davis et al., 1970, 1973, 1975; Wang et al., 1976; Ridley and Mason, 1978; Baker et al., 1979). Notwithstanding this fact several recent articles report good functional results despite significant vertical resorption of the subperiosteal bone (Petzel et al., 1980; Dumbach and Geiger, 1980; Rudelt and Heydarin,

]981).

/

/ /

Fig. 1

Horizontal osteotomy below the neurovascular bundles to

increase the heightof the mandibularalveolarridge (Barros-SaintPasteur, 1966).

Recent Developments in Interpositional Bone-Grafting

]. max.-fac. Surg. 13 (1985)

15

Fig. 2 Vertical-sliding osteotomy (left) with raising of the cranial segment (right), based on lingual pedicle (Barros-Saint-Pasteur, 1970).

In an attempt to overcome the unwanted side effects of onlay grafting, interpositionai techniques were developed to encourage more rapid and more complete incorporation of the grafted tissue into its recipient site. The pioneer in this regard was Barros-Saint-Pasteur (1966). He developed a two-stage procedure involving initial mobilization of the cortical alveolar ridge via a horizontal osteotomy below the nerve, from one retromolar pad to the other (Fig. 1). Three weeks later the cranial segment was elevated, the gap being filled in an interpositional fashion with plaster of Paris, plastic or deproteinized bovine bone. He later refined the technique (Barros-Saint-Pasteur, 1970) into a one-stage procedure and in the same article outlined an alternative approach to the horizontal osteotomy in which the cranial fragment was moved superiorly in a vertical-sliding fashion (Fig. 2). He again used heterologous bone grafts to maintain the elevation. Since that time these two basic techniques have been followed or modified by several workers (Schettler, 1976, 1980, 1982a, 1982b; Schettler and Holtermann, 1977; Hiirle, 1975 a, 1975b, 1976, 1979, 1981, 1982; Bunte et al., 1976; Bunte and Struntz, 1977; Peterson and Slade, 1977; Lekkas, 1977; Lekkas and Wes, 1978, 1981; Bell et al., 1977; Bell and Buckles, 1978; Stoelinga et al., 1978, 1983; Tideman and Stoelinga, 1978; de Koomen et al., 1979; Tideman et al. 1980; Fitzpatrick, 1981; Frost et al., 1982; Hopkins, 1982; Sugar and Hopkins, 1982). The so-called "reverse visor osteotomy" of Stratigos et al. (1982) is mentioned only for completeness. It is neither an osteotomy nor is it performed in a "visor" fashion. It is merely a variation of the Hofer and Mehnert (1964, 1965) operation, a flee bone-graft being transplanted from chin to alveolar ridge in a subperiosteal position. Almost all of the above grafting methods (both subperiosteal and interpositional have demanded a second soft tissue vestibular procedure further to improve the denture base. Attemps to complete both procedures at the same

Table 1

Patient statistics

No. examined Mean age Yrs. edentulous Lower denture problems

54 47 yrs. (25-67) 19 yrs. ( 3 - 4 2 ) 7 yrs. ( 1 - 3 0 )

operation were reported by Brons et al. (1977) and Fitzpatrick (1981). Long-term follow-up of either of these methods is not yet available, although results seem promising in the short-term. Over the past few years it became the policy in this clinic to employ follow-up vestibuloplasty only when indicated on definite clinical grounds. This departure from routine followed a change in the design of the soft tissue incision in the anterior region. The incision is carried down a few millimetres into the vestibule, but care is taken not to include muscle tissue when dissecting the mucosa. This way when suturing, the mucosa will partly cover the bone graft, which in most instances results in the maintenance of acceptable post-operative vestibular depth and form. The prosthodontist (H.d.K.) was able to construct a functional lower prosthesis without recource to further sulcus-deepening procedures. The following study documented the effects of adherence to this protocol. Material and Methods Fifty-four patients who had undergone mandibular augmentation by interposed bone-grafring were examined (Table 1). In 42 cases the standard "one piece" operation was employed (de Koomen et al., 1979) and in 12 cases the "three piece" method (Stoelinga et al., 1983). Surgery was performed by two surgeons (P.S., H.T.) and dentures constructed by one prosthodontist (H.d.K.). The decision to use surgery was based on criteria documented in previous reports (de Koomen et al., 1979; de Koomen, 1982). In the past the protocol demanded routine vestibuloplasty two to three months after surgery, using a free cheek mucosal graft as described by Tideman (1972, 1973). In the present series vestibuloplasty was deliberately avoided. Denture construction was commenced on the operated ridge on average 5.5 months after operation. Relining was necessary in 19 patients, on average 12 months after initial insertion of the prosthesis. Average follow-up time was 20 months (range 4-48). The results were evaluated by questionnaire, clinical examination and cephalometric and orthopantomographic radiographs. Objective assessment was made of mucosal health, ridge shape and form, vestibular depth and complications related to wound healing or wiring techniques. Sensibility disturbances in the lip and chin region were studied using the dual

16

y. max.-fac. Surg. 13 (1985)

Height

PRE

POST

GAIN

14

29

15

Ventral

Frank Moloney et al. that the measurement of an average height in the body region would at least give a reasonable indication of gross changes occurring in that area, and was therefore a worthwhile exercise. Six vertical reference lines were chosen 3, 4 and 5 cm. lateral to the point of intersection of nasal septum and floor of the nose. This point was readily reproducible from one X-ray film to the next. This avoided reliance as a reference point on the mental foramen which many times was not clearly visible (Fig. 4). As the influence of vestibuloplasty on resorption of the mandible would be thought to be maximal in the anterior ventral region, an attempt was made to develop a standardized system of measurement in this area (Fig. 3). A point 15 ram. above Gnathion (Gn) was chosen to represent the ventral area, resorption of the bone-graft measured along a line passing through this point and perpendicular to the ramus line (RL). Previous reports from this clinic measured this change simply from the deepest point on the anterior curvature. Both of these methods were used and the results compared.

~\

L

5

\

A

MP

RL

Fig. 3 Typicalpre- and postoperativetracingsfrom standard cephalograph. Vertical gain is measured anteriorly along line A-Gn, perpendicular to mandibular plane (MP). Ventral loss is measured along line VP-RL. Point VP is 15 mm. above Gn. Ramus line (RL) is tangent of condyle and gonial angle.

Results

Subjective assessment It was found that 70 % sought treatment because of progressive looseness of their lower prosthesis, the remainder either experiencing pain on chewing or seeking aesthetic improvement. Following surgery and new denture construction 36 patients (67 %) were able to wear the lower prosthesis without problems. In the group reporting continuing difficulties with the new lower denture (18 patients, 33 %), the reasons were related equally to persistent jaw pain on chewing and sensibility disturbances (Tables 2 and 3). Of the 16 patients who had experienced jaw pain at any time in the three months prior to the examination, nine cases were related to retained intraosseous wires which had either become loose or superficial in position. All of these wires were subsequently removed, which resulted in relief of their pain. Twelve of 54 patients (22 %) experienced temporary problems with either hip pain or with walking. One had continuing occasional pain related to the scar and one was

methods of light-touch detection and directional movement sense. A fine camel-hair brush was used and the patient's eyes closed during testing. The behaviour of the elevated ridge and the fate of the grafted bone was studied from tracings of the serial radiographs of each patient. Anterior measurements from lateral cephalographs were analysed in the standard fashion as per Fig. 3 (de Koomen et al., 1979). A method was developed to measure vertical changes in the posterior (body) region of the mandible. It is emphasized that the reliability of this latter technique, based on orthopantomographic tracings, is open to question despite the reliance on this X-ray method by several investigators in the past (Wical and Swoope, 1974a, 1974b; Stoelinga et al., 1978; Fazili et al., 1978; van Waas, 1979; Wical and Brussee, 1979). It was thought

AVERAGE

HEIGHTS

Pre-op.

17.0

Post-op.

35.3

Gain

18.3

g112

30.1

% Loss 9/12

.5.2 -- : 28% 18.3

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t

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17

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t1 17

16

18

140 139 39

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133 31

30

Ii 29

26

117117

133133 33 I i

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,-71-4.. ~.J

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27

Fig. 4 Typical orthapantomograph tracing showing preoperative height (large dots), immediate gain (small dots) and position of alveolar ridge at 9 months (broken line). Central vertical line bisects junction of nasal septum and floor of nose. Lateral vertical lines are 3, 4 and 5 cm. from central line.

Recent Developments in Interpositional Bone-Grafting

J. max.-fac. Surg. i3 (1985)

17

ANTERIOR RESORPTION - Cephalometrictracings

30Height

mm

252015I0-

!

I

Pre-op.

Gain (ram)

Immed. Post-op. 13.2 I00 %

12

18

24

8.8 57 %

8.5 6.5 %

8. o 61%

I

36 months Time

10.0

77 %

COMPOSITE DRAWING

7.3 56 ~

Fig. 5 Anterior ridge height at various times postoperatively. Long-term gain at 36 months is 56%.

the 16 ram. in previous groups (Stoelinga et at., 1983). The immediate gain of 13.2 mm. was consistent with past results. The pattern of resorption characteristic of this operation is demonstrated in Fig. 5 and 6. The first 6-12 months was the period of most rapid resorption, stabilizing thereafter, 65 % of the original gain being maintained at the 18-month stage. Approximately 56 % of the initial gain is maintained in the long-term with return to the "physiological" mandibular resorption of 0.3-0.5 mm per year (Tallgren, 1966, 1967, 1972; Atwood and Coy, 1971; Nicol et al., 1979) after the first 12 months. Measurements in the body region (Fig. 7) showed a mean preoperative height of 16 mm. with an immediate postoperative gain of 10 ram. The resorption pattern was significantly different, however, from the anterior region with over 80 % of the gain lost after three years. When considered as a separate group there was a 2 rnm. greater gain in height in the body region using the "three piece" technique which was maintained 12 months after surgery. Ventral resorption in the anterior region was found to be 4.6 ram. using the method of de Koomen et al., (1979) and 5.0 mm. using the standardized method. Sixty-two per cent of the patients described varying degrees of subjective nerve disturbance on average 20 months after surgery. The vast majority experienced occasional "prickling" or "stiffness," only one being disturbed by unilateral hyperaesthesia and one complaining of persistent unilateral anaesthesia (Table 4). In only 9 of 54 patients examined

==============================

Fig. 6 time.

....................... Post - ol3.

27.5 24.5 23.5

mm mm mm

................ Pre- op.

14.5

mm

Composite tracing of changes in anterior bone height with

constantly irritated by numbness over the posterior thigh. This was the only patient in the series where bone was harvested from the posterior ilium, a procedure since abandoned. Seventy per cent were satisfied with the overall results and would have the operation again if necessary.

Objective assessment In this series the mean anterior height of the mandible preoperatively was 14.5 ram. (9-31 mm.) as compared to

Table 3 Table 2

Problems with new prosthesis

Post-operative jaw pain Related to

Related to

No.

Retained wires High genial tubercles Mental nerve Unknown

9 2 -2 3

Retained wire Sensibility disturbance High tubercles Mental nerve pressure Continuing looseness

Total

16

Total

No. 5 4 3 2 2 16

18

J. max.-fac. Surg. 13 (1985)

Frank Moloney et al.

BODY RESORPTION - O.P.G. tracings

30Height

mm

2520-

15105-

i

Pre-op.

Immed. Post-op. Resorption

I

6

12

18

36 months

24 Time

48 %

64 %

70 %

Fig. 8 Arrow points to genial tubercles, at a higher level than raised ridge. Pressure from lingual denture flange caused pain.

74 %

80 %

Fig. 7 Average height in body region posterior to mental foramen at various times postoperatively.

multiple small fraenula extending down into the vestibule when traction was applied to the lower lip. In neither case did it alter denture function. Transosseous wires had become exposed in 14 patients. On no occasion was obvious infection present. In 17 patients (32 %) the genial tubercles were at a higher level than the mandibular ridge (Fig. 8). Modification of the anterior lingual denture flange accomodated this altered situation in all but two cases where pain was present when the denture moved against this area. Both patients were scheduled for genial tuberoplasty. Discussion

(17 %) did nerve disturbance continue to provide a source of annoyance, the complaints ranging from difficulty with eating and drinking to odd sensations seemingly brought on by weather changes. When the "three piece" cases were analysed separately 9 out of 12 (75 %) showed completely normal lip and chin sensation on subjective and objective testing ten months after surgery. Where mucosal condition was concerned two patients exhibited excessive scar contracture in the anterior region with Table 4

Nerve sensibility testing results

Pattern

Normal Anaesthesia Paraesthesia Hypoaesthesia Hyperaesthesia

Brush contact sense Movement appreciation (%) and directional sense (%) 80 % 6% 10 % 0% 4%

50 % 6% 36 % 2% 6%

100%

100%

Despite the fact that 3 patients demonstrated complete anaesthesia, in only one it was registrated as a subjective complaint.

Indications for mandibular vestibuloplasty have been discussed by many authors (HiIlerup, 1979 a, 1979 b, 1982; Teiser and Esser, 1980; Fazili et al., 1981; FrenkeI, 1982; De Koomen et al., 1982). The protocol in this clinic has been outlined elsewhere (de Koomen et al., 1979). An anterior height of 15 or 20 mm., dependent on age, has been the limit below which the interpositional bone-grafting operation has been used in preference to vestibular deepening procedures. In the past mandibular augmentation has been followed by subsequent soft tissue vestibular surgery with the general acceptance that one must inevitably follow the other. The influence of vestibuloplasty on mandibular bone resorption rates had recieved little attention in the past. Hillerup (1979 a, 1979 b) found a significant influence on underlying bone resorption when the sulcus was deepened by the operation of Edlan and Mejchar (1963). The mandibles in his series were characterized by "a bowl-shaped loss of bone" in the anterior region. Joos et al. (1982) found an increased vertical resorption rate in mandibles treated by the vestibuloplasty method of Schuchardt (1952). Patients who experienced a vertical loss of 0.2-0.5 mm in the year prior to surgery had an average of 1 mm. resorption in the first year postoperatively. Hjorting-Hansen et al. (1983) documented 1.7 mm. loss of anterior height in the symphysis region in the first year after vestibuloplasty using free

Recent Developments in lnterpositional Bone-Grafting

J. max.-fac. Surg. 13 (1985)

19

1.8 Cu

A. B. C.

Transverse bone cut Elevated+ buccally displaced lingual segment Interposed bone block

skin grafting, with no further increase in loss thereafter. A vestibuloplasty six weeks after the visor-osteotomy is considerably more difficult to perform than in normal cased according to Hiirle (1979). This has also been the experience of these authors. Submucosal fibrosis in the healing phase alters normal surgical planes making supraperiosteal dissection difficult. The benefits of a conservative approach with employment of follow-up vestibuloplasty only when indicated have been clearly borne out by this study. Not only was short-term bone resorption (18 months) positively influenced, but sensibility disturbances were also greatly reduced. Denture construction on the elevated ridge was almost universally successful, only two cases still exhibiting indications for vestibuloplasty in the long-term. The bone resorption pattern in the anterior ventral region was clearly altered by this change in protocol. The 5 mm. and 4.6 mm. figures measured in this series by the two methods closely match the 5.5 mm. ventral resorption as recorded in a previous group of 40 patients in whom vestibuloplasty was also avoided (de Koomen, 1982). When compared with the figure of 7 mm. ventral resorption experienced in a previous group of 50 patients treated with both operations (de Koomen et al., 1982) this represents a 29 % reduction. Disturbance of the periosteum overlying the newly established bone-grafted alveolar ridge would seem from these results to hasten resorption of the graft at least in a ventral direction. The opinion was previously held by the senior authors that bone resorption in the bicuspid-molar regions was "much the same as that measured in the symphysis" (Stoelinga et al., 1983). Because of difficulties of standardization of measurement in this area, a separate analysis was not usually performed, only anterior changes being recorded. This study supports the clinical impression gathered over the years that most of the bone placed posterior to the mental foramen will behave as if it Were a subperiosteal graft. However, the improvement in form and shape provides a degree of "rounding-off" and prevents an abrupt "dip" in the alveolar ridge in the mental foramen region,

Fig. 9 Tracing of panoramic X-ray after ,,THREE PIECE" osteotomy. Posterior bone blocks (shaded areas) are interposed between cranial segment and body of mandible. Note transverse bone cut in retromolar pad to determine position of nerve.

and continues to justify surgery in the body region of the mandible. The future prospects for the "three piece" operation would seem to be encouraged by the preliminary results reported here. Not only can the ridge height be increased to a greater extent but a slower resorption rate appears to be an added benefit. The rapid and almost complete resorption of the elevated ridge and associated bone-graft in the posterior region has several possible explanations. The "one piece" technique places a relatively sharp and narrow ridge in an elevated position which atrophies rapidly with denture wear. The grafted bone is laid alongside the elevated posterior segment as compared to the anterior region where it is truly interpositional in character. The history of subperiosteal bone-grafts is well established and is supported by the behaviour of the posterior grafts in this study. The nerve disturbances in this study were objectively assessed by means of standard tests. Even the slightest disturbance was noted, which to some extent overemphasized the significance of these findings. As mentioned before only 9 out of 54 patients considered their loss of sensations as a constant source of annoyance. A general improvement in nerve disturbance incidence was seen (50 % with paraesthesia at 20 months as compared to 80 % after 2-3 years in the past). This attests not so much to a gradual improvement in surgical skills as to the rationale of leaving the neurovascular bundle undisturbed. Isolation and retraction of the nerve is no longer recommended. Advice to the contrary in recent papers (Hopkins, 1982; Sugar and Hopkins, 1982) cannot be supported. Studies by Hiirle (1977) and Reich (1980) demonstrate clearly the bucco-lingual disposition of the neurovascular canal as it courses forwards in the body of the mandible. The position of the nerve can be determined using a small transverse bone cut in the retromolar pad area, as previously described (Stoelinga et at., 1983) and seen on the Xray tracing (Fig. 9). There is then sufficient room to place the sagittally directed vertical osteotomy cut lingual to the neurovascular bundle if a fine tapered fissure bur is used.

20

J. max.-fac. Surg. 13 (1985)

Frank Moloney et al. Immed. post-op. ......... 3 months post-op.

f--==

....,,°'.% \ °',°°_ Z

~d, Postop.

ii

o 4

-ol Fig.10a Dorsal collapse: superimposed tracings of anterior ridge at different times. Inset shows anterior cranial segment preop. (solid line) immediately postop, (dotted line) and at three months (broken line).

•

ee

+

Fig. 10 b Superimposed tracings of twin circum-mandibular wires demonstrate degree of posterior collapse. Immediately postop. (solid lines) and at three months (dotted lines).

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't'," I••O•

......

OI O1•

"°° • °

~

Fig, 11 a Outline of three separate segments to be elevated. Arrows lie on lingual cortex.

Fig. 11 b Completed "THREE PIECE" osteotomy. Note change in direction of arrows from (a) indicating 90 degree movement of lingual segment. Corticocancellous bone struts (black) support anterior cranial segment. Central figure-of-8 wire and 2 lateral circum-mandibutar wires complete fixation.

Recent Developments in Interpositional Bone Grafting

]. max.-fac. Surg. 13 (1985)

2]

Fig. 12 Arrow points to "fracture" of Jower border on removal of figure-of-8 wire.

Irrespective of the method of treatment of the posterior segment ("one piece" versus "three piece") there has so far never been a need to lower the floor of the mouth in the posterior region by a subsequent operation. Restoration of a lingual sulcus in this region which is of sufficient depth and sufficiently free of muscle tension would seem to be a natural phenomenon. The anatomical form and function of this area must meet various criteria dependent on the prosthodontist. Thus far no additional alteration has been demanded by that member of our team (H.d.K.) in over 200 patients treated by interpositional bone-grafting. Various wiring techniques have been employed over the years to stabilize the elevated segment. A pictorial review of these methods can be found in Stoelinga et al., (1983). Dorsal collapse of the anterior segment (Figs. 10a and b) has not been seen since a technique combining an anterior figure-of-8 wire with two lateral circum-mandibular wires has been used routinely. This figure-of-8 wire (Fig. 11 b) allows anterior traction on the elevated segment at the time of surgery and places the cranial fragment in a more anterior position over the base of the mandible. It would also appear to be the key to early postoperative stability. However, subsequent removal of this wire may be difficult under local anaesthesia. In the case illustrated in Fig. 12, this wire has pulled through the lower border of the caudal segment during its removal. Complete consolidation (2-3 months) should be present before attempts to remove this particular wire are made. The biological basis for interposed bone-grafts to the mandible has been clearly established in animal experiment (Canzona et al., 1976; Danielson and Nemarrich, 1976; Frame et al., 1981, 1982). Elevation and lateral transposition of the posterior lingual segment in the "three piece" operation (Fig. 11) places the cancellous bone blocks in a truly interposed position and the early results attest to the benefits of this modification. How best to rebuild the atrophic body of the mandible posterior to the mental foramen remains as yet unanswered. Whether success lies in fufure variations of the standard "VISOR-SANDWICH" osteotomy, the use of the new "THREE PIECE" technique or the employment of subperiosteal or interposed implant materials such as hydroxyl-apatite (Kent et al., 1980; Frame, 1983) remains for future studies to determine,

Conclusions Mandibular augmentation by the interpositional bonegrafting method has stood the test of time. Constant reappraisal of treatment results is necessary if significant improvements are to be achieved. This study provides evidence that most patients can be spared a follow-up vestibuloplasty after interposed bone-graft augmentation. The decision to employ this second operation should be based on clinical indications and not performed as a matter of routine. Rebuilding the body of the mandible posterior to the mental nerve remains a surgical challenge. Further studies are necessary to determine the ideal approach to this difficult area.

Acknowledgements The primary author (F,M.) sincerely appreciates the considerable help of Dr. Guido de Troyer in his translation of the Dutch and German literature, and that of Mrs. Marjan Boehmer-Vuurman for her assistance with the Spanish language papers of Barros-Saint-Pasteur.

References Atwood, D. A., W. A, Coy: Clinical, cephalometric, and densitometric study of reduction of residual ridges. J. Prosthet. Dent. 26 (1971) 280 Baker, R. D., B. C. Terry, W. H. Davis, P. W. Connole: Long-term results of alveolar ridge augmentation. J. Oral Surg. 37 (1979) 486 Barros-Saint-Pasteur, J.: plastica restauradora de la cresta alveolar de la mandibula (prima imforme). Acta Odontol. Venez. 4 (1966) 2 Barros-Saint-Pasteur, J.: Plastica reconstructiva del reborde alveolar. Nuestra investigacion clinico-quirurgica. Acta Odontol. Venez, 8 (1970) 168 Bell, W. H., W. A. Buche, J. W. Kennedy IlI, J. P. Ampil: Surgical correction of the atrophic alveolar ridge. A preliminary report on a new concept of treatment. Oral Surg. 43 (1977) 485 Bell, W. H., R. L. Buckles: Correction of the atrophic alveolar ridge by interposed bone-grafting: a progress report. J. Oral Surg. 36 (1978) 693 Brons, R., R. Bosker, L. van Dijk: Visor osteotomy and vestibuloplasty - a one stage procedure. A preliminary report. Int. J. Oral Surg. 6 (1977) 127 Bunte, M., V. Struntz, K. Bitter, H. Br6mer: Augmentations-Plastik des atrophischen Unterkiefer-Alveolarfortsatzesmit Glaskeramik. Dtsch. Zahnfirztl. Z. 31 (1976) 458

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]. max.-fac. Surg. 13 (1985)

Bunte, M., V. Struntz: Ceramic augmentation of the lower jaw. J. max.-fac. Surg. 5 (1977) 303 Canzona, J. E., N. G. Grand, J. P. Waterhouse, D. M. Laskin: Autogenous bone grafts in augmentation of the edentulous canine mandible. J. Oral Surg. 34 (1976) 879 Danielsen, P. A., A. F. Nemarrich: Subcortical bone grafting for ridge augmentation. J. Oral Surg. 34 (1976) 887 Davis, W. H., R. L Delo, J. R. Weiner, B. Terry: Transoral bone graft for atrophy of the mandible. J. Oral Surg. 28 (1970) 760 Davis, W. H., R. I. DeIo, J. R. Weiner, B. Terry: Transoral rib grafting for mandibular alveolar atrophy - a progress report. In: Transactions of the 4th International Conference on Oral Surgery. L. W. Kay (Ed.) Munksgaard. Copenhagen (1973) pp. 206-209 Davis, W. H., R. I. Delo, W. B. Ward, B. Terry, B. Patakas: Long-term ridge augmentation with rib grafts. J. max.-fac. Surg. 3 (1975) 103 Dumbach, J., S. A. Geiger: Klinische und radiologische Befunde bei absoluter Alveolarkammerh6hung im Unterkiefer durch autologe Rippentransplantate. Dtsch. Zahn~irztl. Z. 35 (1980) 1003 Edlan, A., B. Mejchar: Plastic surgery of the vestibulum in periodontal therapy. Int. Dent. J. 13 (1963) 593 Fazili, M., G. R. van Overvest-Eerdman, A. M. Vernooy, W. J. Visser, M. A. J. van Waas: Follow-up investigation of reconstruction of the alveolar process in the atrophic mandible. Int. J. Oral Surg. 7 (1978) 400 Fazili, M., M. A. J. van Waas, M. H. Houwing, P. J. Slootweg, G. R. van Overvest-Eerdman: Long-term results of vestibuloplasty of the mandible. Int. J. Oral Surg. 10 Suppl. 1 (1981) 77 Fitzpatrick, B. N.: Visor/Sandwich osteotomy. Int. J. OraI Surg. 10 (1981) 87 Frame, J. W., C. L. Brady, R. M. Browne: Augmentation of the edentulous mandible using bone and hydroxylapatite: a comparative study in dogs. Int. J. Oral Surg. 10 Suppl. 1 (1981) 88 Frame, J. W., R. M. Browne, C. L. Brady: Biological basis for interpositionaI autogenous bone grafts to the mandible. J. Oral Maxillofac. Surg. 40 (1982) 407 Frame, J. W.: Personal Communication (1983) FrenkeI, G.: Prfiprothetische Eingriffe aus heutiger Sicht. Dtsch. Zahn~irz. Z. 37 (1982) 76 Frost, D. E., J. M. Gregg, B. C. Terry, R. J. Fonsceca: Mandibular interpositional and onlay bone grafting for treatment of mandibular bony deficiency in the edentulous patient. J. Oral Maxillofac. Surg. 40 (1982) 353 Hiirle, F.: Visierosteotomie des atrophischen Unterkiefers zur absoluten Kammerh6hung. Dtsch. Zahnfirtz. Z. 30 (1975 a) 561 Hdrle, F.: Visor osteotomy to increase the absolute height of the atrophied mandible. J. max.-fac. Surg. 3 (1975 b) 257 Hiirle, F.: Visierosteotomie zur absoluten Erh6hung des atrophischen Unterkiefers. In: Fortschritte der Kiefer- und Gesichtschirurgie, Bd. XX, K. Schuchardt, G. Pfeifer (Eds.), Georg Thieme Verlag, Stuttgart (1976) S. 149 Hiirle, F.: Die Lage des Mandibularkanals im zahnlosen Kiefer. Dtsch. Zahn~irzt. Z. 32 (1977) 275 Hiirle, F.: Follow-up investigation of surgical correction of the atrophic alveolar ridge by visor osteotomy. J. max.-fac. Surg. 7 (1979) 283 Hiirle, F.: Long-term results with the visor-osteotomy. Int. J. Oral Surg. 10 Suppl. 1 (1981) 83 Hiirle, F.: Indikation, Methoden und Ergebnisse zur absoluten Alveolarkammerh6hung des Unterkiefers. Dtsch. Zahn~irtz. Z. 37 (1982) 121 Hillerup, S.: Preprosthetic vestibular sulcus extension by the operation of Edlan and Mejchar. Int. J. Oral Surg. 8 (1979 a) 333 Hillerup, S.: Profile changes of bone and soft tissues following vestibular sulcus extension by the operation of Edlan and Mejchar. Int. J. Oral Surg. 8 (1979 b) 340 Hillerup, S.: Preprosthetic mandibular vestibuloplasty with buccat mucosal graft. Int. J. Oral Surg. 11 (1982)81 Hjorting-Hansen, E., A. M. Adawy, S. Hillerup: The pattern of postoperative bone resorption following mandibular vestibulolingual sulcoplasty with free skin graft. J. Oral Maxillofac. Surg. 41 (1983) 358

Frank M o l o n e y et al. Hofer, 0., H. Mehnert: Eine neue Methode zur Rekonstruktion des Alveolarkammes. Dtsch. Zahn-, Mund- und Kieferheilk. 41 (1964) 353 Hofer, 0., H. Mehnert: Der Aufbau des atrophischen A!veolar-Fortsatzes dutch Knochentranspostion. In: Fortscbritte der Kiefer- und Gesichtschirurgie. Bd. X, K. Schuchardt (Ed.) Georg Thieme Vetlag, Stuttgart (1965) pp. 42~44 Hopkins, R.: A sandwich mandibular osteotomy: a preliminary report. Brit. J. Oral Surg. 20 (1982) 155 Joos, U., W. Gernet, F. Muzzulini: Die Resorption des Unterkiefers nach Vestibulumplastik und Mundbodensenkung. Dtsch. Zahn~irtz. Z. 37 (1982) 117 Kent, J., J. R. I. Finger, M. Jarcho, J. Taggart, S. Cook: Augmentation of deficient edentulous alveolar ridges with dense polycrystalline hydroxyapatite. First World Biomaterials Congress (Baden, Austria) 1980 3.8.2 (abstract) De Koomen, H. A., P. J. W. Stoelinga, H. Tideman, A. J. M. Huijbers: Interposed bone-graft augmentation of the atrophic mandible (a progress report). J. max.-fac. Surg. 7 (1979) 129 De Koomen, H. A.: De verhoging van de geresorbeerde mandibula (Interposed bone-graft augmentation of the mandible). Thesis, University of Nijmegen, The Netherlands, 1982 De Koomen, H. A., H. Tideman, P. J. W. StoeIinga, A. J. M. Huijbers, F. H. J. Hendriks: Indikation, Technik und Ergebnisse der Unterkiefervestibulumplastik und Mundbodensenkung. Dtsch. Zahn~irtz. Z. 37 (1982) 509 Lekkas, K.: Absolute heightening of the mandible. Int. J. Oral. Surg. 6 (1977) 147 Lekkas, K., B. J. Wes: De absolute verhoging van de onderkaak. Ned. Tijdschr. Tandheelkd. 85 (1978) 5 Lekkas, K., B. J. Wes: Absolute augmentation of the extremely atrophic mandible (a modified technique). J. max.-fac. Surg. 9 (1981) 103 Nicol, B. R., G. W. Somes, Ch. W. EIlinger, J. W. Unger, J. Fuhrmann: Patient response to variations in denture technique. Part II. Five year cephalometric evaluation. J. Prosthet. Dent. 41 (1979) 368 Peterson, L. J., E. W. Slade: Mandibular ridge augmentation by a modified visor osteotomy: a preliminary report. J. Oral Surg. 35 (1977) 999 Petzel, J. R., St. Haase, J. Kreidler: Ergebnisse der relativen und absoluten Alveolarkammplastik im Unterkiefer. Dtsch. Zahn~irtz. Z. 35 (1980) 1000 Reich, R. H.: Anatomische Untersuchungen zum Verlauf des Canalis Mandibularis. Dtsch. Zahn~irzt. Z. 35 (1980) 972 Ridley, M. T., K. G. Mason: Resorption of rib graft to inferior border of the mandible. J. Oral Surg. 36 (1978) 546 Rudelt, H. F., F. Heydarian: Alveolarkammerh6hung durch autologe Rippentransplantation mit anschlief~ender Vestibulum-Plastik (Behandlungsergebnisse). Dtsch. Z. Mund-, Kiefer- Gesichts-Chir. 5 (1981) 345 Schettler, D.: Sandwichtechnik mit Knorpeltransplantat zur Alveolarkammerh6hung im Unterkiefer. In: Fortschritte der Kiefer- und Gesichtschirurgie. Bd. XX, K. Schuchardt (Ed.), Georg Thieme Verlag, Suttgart (1976) pp. 61-63 Schettler, D., W. Holtermann: Clinical and experimental results of a sandwich-technique for mandibular alveolar ridge augmentation. J. max.-fac. Surg. 5 (1977) 199 Schettler, D.: Modifizierte Technik der Sandwichplastik ffir extrem atrophierte Unterkiefer. Dtsch. Zahnfirtz. Z. 35 (1980) 994 Schettler, D.: Sp/itergebnisse der absoluten Kieferkamm-Erh6hung im atrophischen Unterkiefer durch die ,,Sandwichplastik". Dtsch. Zahn/irtz. Z. 37 (1982 a) 132 Schettler, D.: Variation der Sandwich-Osteotomie zur Stabilisierung des Transplantates - personal communication - (1982 b) Schuchardt, K.: Die Epidermistransplantation bei der Mundvorhofplastik. Dtsch. Zahniirtz. Z. 7 (1952) 364 Stoelinga, P. J. W., H. Tideman, J. S. Berger, H. A. de Koomen: Interpositionat bone-graft augmentation of the atrophic mandible: a preliminary report. J. Oral Surg. 36 (1978) 30 Stoelinga, P. J. W., H. A. de Koomen, H. Tideman, A. J. M. Huijbers: A reappraisal of the interposed bone graft augmentation of the atrophic mandible. J. max.-fac. Surg. 11 (1983) 107

R e c e n t D e v e l o p m e n t s in I n t e r p o s i t i o n a l B o n e - G r a f t i n g Stratigos, G. T., A. Cassara, M. Brinbaum: Reverse visor osteotomy for augmentation of the atrophic edentulous mandible. J. Oral Maxillofac. Surg. 40 (1982) 231 Sugar, A., R. Hopkins: A sandwich mandibular osteotomy: a progress report. Brit. J. Oral Surg. 20 (1982) 168 Tallgren, A.: The reduction in face height of edentulous and partially edentulous subjects during long-term denture wear. A longitudinal r6ntgenographic study. Acta Odontol. Scan& 24 (1966) 195 Tallgren, A.: The effect of denture wearing on facial morphology. A 7 year longitudinal study. Acta Odontol. Scan& 25 (1967) 563 Tallgren, A.: The continue reduction of the residual alveolar ridges in complete denture wearers: a mixed longitudinal study covering 25 years. J. Prosthet. Dent. 27 (1972) 120 Teiser, ]., E. Esser: Metrische Untersuchungen nach VestibulumPlastik mit freier Schleimhaut. Dtsch. Zahn~irtz, Z. 35 (1980) 979 Tidernan, H.: A technique of vestibuloplasty using a free mucosal graft form the cheek. Int. J. Oral Surg. 1 (1972) 76 Tideman, H.: Vestibulumplastiek met het vrije mucosatransplantaat. Thesis, University of Amsterdam, The Netherlands, 1973 Tidernan, H., P. J. W. Stoelinga: Erh6hung des atrophischen Unterkiefers mit Beckenknochentransplantat. Dtsch. Z. Mund-, KieferGesichts-Chir. 2 (1978) 107 S Tideman, H., P. J. W. Stoelinga, H. A. de Koomen: Die Erh6hung des atrophierten Unterkiefers mit Beckenknochentransplantat. Dtsch. Zahn/irtz. Z. 35 (1980) 1011 Van Waas, M. A. J.: Een r6ntgenologisch onderzoek naar de resultaten van autologe bottransplantaten. Ned. Tijdschr. Tandheelkd. 86 (1979) 25 Wang, J. H., D, E. Waite, E. Steinhauser: Ridge augmentation: an evaluation and follow-up report. J. Oral Surg. 34 (1976) 600

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Wical, K, E., C. C. Swoope: Studies of residual ridge resorption. Part I. Use of panoramic radiographs for evaluation and classification of mandibular resorption. J. Prosthet. Dent. 32 (1974 a) 7 Wical, K. E., C. C. Swoope: Studies of residual ridge augmentation. Part II. The relationship of dietary calcium and phosphorus to residual augmentation. J. Prosthet. Dent. 32 (1974 b) 13 WicaI, K. E., P. Brussee: Effects of a calcium and vitamin D supplement on alveolear ridge resorption in immediate denture patients. J. Prosthet. Dent. 41 (1979) 4

Frank Moloney D.D.S., M.D. ,,Alexandra" 201 Wickham Terrace Brisbane Q 4000 Australia Paul ]. W. 8toelinga, D.D.S., M.D. Consultant, Department of Oral and Maxillofacial Surgery Gemeente Ziekenhuis 6800 EE Arnhem - The Netherlands Henk Tideman, D.D.S., M.D. Professor of Oral and Maxillofacial Surgery University of Adelaide 8A 500I Australia Hans A. de Koomen, D.D.S. Head, Department o( Maxillo(acial Prosthodontics University of Nijmegen Nijmegen - The Netherlands Gemeente Ziekenhuis 6800 EE Arnhem - The Netherlands