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Aetiology and incidence of facial fractures in adults
Int. J. Oral Surg. 1983: 12: 293-298 (Key words: jracllIres,Jacial; !rac/lire. aetiology; s!lrgery, oral)
Aetiology and incidence of facial fractures in adults 1. M. BROOK AND N. WOOD
Department of Dental and Oral Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, Scotland,
UK
The incidence, aetiology and trends in fractures of the facial bones occurring in the years 1965, 1970, 1975 and 1980 in the Grampian Region of Scotland are reported. A 2.7 fold increase in incidence occurred during this period. Males are seen to be most at risk and an increase in assault and sports-related trauma is seen. Offshore oil exploration developed during this period and its effects are discussed. Attention is drawn to the differences in the aetiology of right and left malar fractmes. ABSTRACT -
(Received for publication 13 December 1982, accepted 5 March 1983)
Data on the aetiology in facial trauma is sparse; it is necessary to have this information when considering aspects of future prevention and quantifying demand for services. Changes in the nature of trauma with time also occur and it is important to evaluate aetiology and aspects of present prevention, together with changes in industrial and environmental factors. The incidence of fractures of the facial skeleton (excluding fractures of the nasal bones and fractures of the mandibular condyle alone), in adults treated in the Grampian Region of Scotland has been studied. Data was obtained retrospectively from the case histories of patients admitted for treatment on an in-patient basis during the years 1965, 1970, 1975 and 1980 in Grampian Health Board hospitals. The topography of the Grampian Region and a centralised maxillo-facial service in the City
JIICIIL,,\:':J) REGION 4.1%
Other Are3.J of UK (5.S%)
Overseas (I.S%)
Fig. I. Geographical distribution of fracture cases treated during the years 1965, 1970, 1975 and 1980, based on the patient's permanent residence. N=290.
294
BROOK AND WOOD
Table 1. Number of nights spent in hospital for each fracture type
left malar right malar mandible maxilla
Mean no.
Standard deviation
S.E.M.
2.76 4.38 5.45 13.26
2.22 5.82 7.45 12.67
0.245 0.735 0.694 2.43
Maxillary fractures stayed significantly longer than other types. Mandibular fractures stayed significantly longer than left malar. (P < 0.05). At the 90% confidence interval, right malar stayed longer than left malar, mandibles stayed longer than all malars.
THE NO OF FACIAL FRACTURES GRAMPIAN REGiON PER 500000 POPULATION 1965 - 80
120 110 100
90 80 70
60
of Aberdeen has enabled the study of a "closed" population with well-documented records. Fig. 1 indicates the geographic origin of the patients studied. N = 290.
50 40 30
.... :::: ::::: .....
20
Results The results are shown in Figs. 2-7 and Table I.
Discussion During the period of study, the incidence of fractures in the population under consideration had increased by 270%, while the increase in population was only 7%. The majority of this increase is due to an increase in the number of fractures amongst males (Fig. 2). All types of fracture have progressively increased (Fig.. 3), and the proportion of each fracture type has remained fairly constant. By considering each type of fracture in isolation, with regard to its aetiology, some marked differences can be seen. Fractured malars (zygomatic complex) were the most common facial fracture seen,
10
o
;.:.
65
Male •
70
~~;~ .... ~~~~ ....
i....!~!
.... .... .... .:.:
75
80
Year
Female
m
Fig. 2. Number of facial fractures, Grampian Region per 500,000 population 1965-1980.
in contrast to previous surveys9-11 (fractured nasal bones excluded) of past decades, but in agreement with other recent surveys t. When comparing the aetiology and incidence of right and left malar fractures (instead of a random distribution), distinct trends in the pattern of trauma emerged (Fig. 4). It has previously been reported S that malar fractures due to fights, falls and sports show a higher preponderance to
295
FACIAL FRACTURES THl! Olstn,BUTION OF FAAI:YURI::S llY FfMCTUIH;S TyPE FOR THE YEARS 105!i, '~70. 1~75, 1980 60
'il.
60
No of Casr\ each year
No of G'iue~ in ttla.lir.lI\ 10 Ihe IOlal No .... f Cilie, ilith Yllar
60 40
10
6510 75 BO Right Mala,
65 70 15
eo
laft Malat
65 7D 75 80 All Malu
66 70 75
eo
M,Jndi\lll
••11
.,5 10 76 80 Ma~llia
(LeForll
Fig. 3. DistributiDn of fractures by fracture type fDr the years 1965,1970, 1975 and 1980. (a) % Df
cases in relation to the total number of cases each year. (b) Number of cases each year.
affect the left side rather than the right. The present study showed a significant difference (P
FRACTURES LEFT AND RIGHT MALAR DIFFERENCE ACCORDING TO AETIOLOGY
100
90
ill
•
80 70 60 50 40 30 20 10 0
BREAKDOWN OF FRACTURE TYPE BY % AETIOLOGY
Left Malar were more common than Right Malars: Industrial (NS), fall, (NS), assauit' (P < 0.051 Right Malar were more common than Left Malars: Sports (P < 0.1 NS), RTA (NS)
Malar RIL (148) R.t., assaults
Right
sports fall'
Left
industrial oil related
I II iI I
M,ndible
(115)
R.t.a
assaults sports fall' industrial
oil related
.:::::.
·}iIII
~~1~~
·:~I~:
~~~~~l
::::::
Assaults 44
Sports
sports
fall' industrial
Fig. 4. Fractures of right and left malar, dif-
oil ralated
17
Falls 35
(27)
R.t.a assaults
Industrial
No;-
RTA 34
Maxilla
18
ferences according to aetiology. Left malars were more common than right malars, in industrial injuries, falls and significantly so in assaults (P
o
'0
20
30 40 50 Porcentage
60
70
Fig. 5. Breakdown of fracture type by % aetiology. N=290.
296
BROOK AND WOOD
to the face. All the females who received facial fractures in a sporting context did so from an equestrian accident (indicating participation). Fractures of the mandible were the second commonest type of facial fracture in our survey. Blows being sustained during the course of a fight from fists or feet, were the commonest cause of fractured man~ dibles as in other surveys4. 7 • Fig. 5 compares the aetiology of each fracture type, the more severe injuries tending to be caused by the more violent trauma!. Fractures of the maxilla (Le Fort type) formed the smallest group, the main aetiologies being road traffic accidents, "oil-related" industrial accidents and falling from heights. Over the period of study, a marked increase in the number of fractures relating to interpersonal violence was observed, especially since
1970 (Fig. 6); this can now be considered the commonest cause of facial fractures in the Grampian Region. There has also been an increase in the number of and overall % of sports injuries since 1970, although the number of cases in this study is not great. The increase in facial fractures due to assaults, making them the commonest aetiology as in other parts of the UK 8 ; may be due to changes in the structure of the local economy, as well as an increase in violence generally in today's society3. During the period of study, the Grampian Region has become the main UK support aera for a large offshore oil industry. This has lead to a transient population of well paid young men who work for long periods offshore and return to Aberdeen with money to spend and a natural desire to enjoy themselves; their pent-up exuberance
THE DISTRIBUTION OF FRACTURES BY AETIOLOGY FOR THE YEARS 1965, 1970, 1975,1980
... 8-
~
g
40
% No of cases in relation to the total No of cases each year
30
11111 40
1•••
111111.. .. -_
No of cases each year
30
N20
1l 'l5
o 10
z
o
_ _ E::::lffiill
65 70 75 80 RTA
65 70 75 80 Assaults fights
65 70 75 80 Sports
65 70 75 80 Falls
65 70 75 80 Industrial accidents
65 70 75 80 Oil related accidents
Fig. 6. Distribution of fractures by aetiology for the years 1965, 1970, 1975 and 1980. (a) % of cases in
relation to the total number of cases each year. (b) Number of cases each year.
FACIAL FRACTURES NO OF FACIAL FRACTURES
1965, 1970, 1975, 1980 INDICATING THE NO OF CASES WITH MULTIPLE TRAUMA
120
m
•
Total No of cases
No of cases with·multiple concomitant In'juries
Fig. 7. Number of facial fractures 1965, 1970, 1975 and 1980, indicating the number of cases
with concomitant injuries. malar significant. P<0.05.
Difference R/L
may account for some of the increase in assaults. Alcohol plays a prominent rOle in many cases; data on this is difficult to obtain as it is not always the patient who is the imbiber. The increase in sports injuries perhaps reflects an increase in affluence and/or leisure time (Fig. 6).
297
The % of onshore industrial accidents has declined, reflecting a decline in traditional industries and perhaps more stringent safety measures. Injuries due to the developing oil industry have increased with the greater number of offshore employees (100 + in 1965; 16,500+ in 1980) in fIxed installations. Injuries sustained in this fIeld, as well as the more traditional fishing industry, tend to be of a more severe nature and common aetiologies are the whiplash effect of breaking wire ropes/chains hitting the face causing severe compound fractures. Falls from scaffolding also account for offshore injuries. The overall effect of the oil industry in facial trauma without comparison with a similar area not having an offshore industry is difficult to evaluate; a further comparative study needs to be done. It is difficult to estimate the degree of trauma required to cause a particular type of facial injury, as the fracture type depends upon many variable factors; direction of the blow, the individuals bone structure, presence of teeth and atrophy/pathology, etc. However, the length of time the patient is kept in hospital is an indication of the degree of trauma as well as the type of treatment required. As would be expected, maxillary fractures were hospitalised significantly longer than other types (Table 1) and this reflects their more complex treatment and associated injuries (Fig. 7). Mandibular fractures, the majority of which received some form of intermaxillary fixation, were also hospitalised for a longer period than malar fractures. An unexpected difference (90% confidence interval) was noted between right and left malar factures, right malars being hospitalised for longer periods than left malars, despite identical treatment (Gillies temporal elevation 2). This could reflect the cause of injury, those on the right having statistically significantly (P < 0.05) more associated injuries (Fig. 7) which delay discharge from hospital, further emphasis-
298
BROOK AND WOOD
ing the different pattern in aetiology between right and left malar fractures (Fig. 4). Facial trauma in the Grampian Region has increased during the period under study; the reasons for this appear to be an increase in interpersonal violence; prevention in this area is a social responsibility and it is hoped that this article may provoke thought on this matter - sporting activity due to increased leisure time and individual participation. Sports injuries are likely to be more common in the future; an awareness of the risks by participants, the adherance to the rules and safety factors, training and supervision could all help to reduce the incidence of facial injuries in amateur sports for both men and women. The use of mouthguards may help to prevent dental trauma 6 in children, affecting the teeth and alveoli, but will not prevent the high incidence of fractured malars and the more severe facial fractures seen in adult sportsmen. Road traffic accidents account for a high % of facial injuries especially those of a more serious nature. Facial injuries from this cause have continued to increase although to a lesser extent than sports- and assault-related trauma. The introduction of seat belts and in the UK their compulsory use since 1983 is an important aspect of prevention, the effect of which could be evaluated in future years by comparison with data reported here. Motor cycle injuries and pedestrian related trauma are areas where further prevention could be undertaken. Acknowledgement: We thank Mr. P. B. Clarke and Mr. N. W. Kerr, Consultant Oral Surgeons, Aberdeen Royal Infirmary and the Records Department, Aberdeen Royal Infirmary for making the patient histories available.
References 1. ALZELIUS, L. E. & ROSEN, C.: Facial fractures. Int. J. Oral Surg. 1980: 9: 25-32. 2. GILLIES, H. D., KILNER, T. P. & STONE, D.: Fractures of the malar zygomatic compound with a discription of a new X-ray position. Brit. J. Surg. 1927: 14: 651. 3. HAIDAR, Z.: Fractures of the zygomatic complex in the south-east region of Scotland. Brit. J. Oral Slirg. 1977: 15: 265-267. 4. HARNISH, H.: Five-year statistics of jaw fractures. Zalmartl. Prax. 1959: 10: 126. 5. HITCHEN, A. D. & SHUKER, S. T.: Some observations on zygomatic fractures in the eastern region of Scotland. Brit. J. Oral Slirg. 1973: 11: 114-117. 6. JARVINEN, S.: On the causes of traumatic dental injuries with special reference to sports accidents in a sample of Finnish children. Acta Odont. Scaml. 1980: 38: 151-\54. 7. LINDSTROM, D.: A comparative survey of jaw fractures during the years 1948-1958. Dent. Abstr. Chicago 1960: 5: 596. 8. McDADE, A. M., McNICOLL, R. D., W ARDBOOTH, P., HESWORTH, J. C. & Moos, K. F.: The aetiology of maxillofacial injuries with special reference to alcohol abuse. Int. J. Oral SlIrg. 1982: 11: 152-155. 9. ROWE, N. L. & KILLEY, H. C.: Fractures of the facial skeleton Edinburgh: Livingstone, 1969. \0. SCHUCHARDT, K. N., SCI-IWINZER, B., ROTTKE, E. N. & LENTRODI, J.: Ursachen, Hiiugigkeit und Lokalinalian der Frakturen des Gesuchtischadels. Fortichr., Keefer-II. Gesichto-Chis. \966: 11: 1. II. WALDEN, R. H., WOHLGEMUTH, P. R. & FITZGIBBON, J. M.: Fractures of the facial bones. Am. J. Surgery 1956: 92: 915-919.
Address:
I. M. Brook Department of Dental Surgery Charles Clifford Dental Hospital University of Sheffield England
Aetiology and incidence of facial fractures in adults 1. M. BROOK AND N. WOOD
Department of Dental and Oral Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, Scotland,
UK
The incidence, aetiology and trends in fractures of the facial bones occurring in the years 1965, 1970, 1975 and 1980 in the Grampian Region of Scotland are reported. A 2.7 fold increase in incidence occurred during this period. Males are seen to be most at risk and an increase in assault and sports-related trauma is seen. Offshore oil exploration developed during this period and its effects are discussed. Attention is drawn to the differences in the aetiology of right and left malar fractmes. ABSTRACT -
(Received for publication 13 December 1982, accepted 5 March 1983)
Data on the aetiology in facial trauma is sparse; it is necessary to have this information when considering aspects of future prevention and quantifying demand for services. Changes in the nature of trauma with time also occur and it is important to evaluate aetiology and aspects of present prevention, together with changes in industrial and environmental factors. The incidence of fractures of the facial skeleton (excluding fractures of the nasal bones and fractures of the mandibular condyle alone), in adults treated in the Grampian Region of Scotland has been studied. Data was obtained retrospectively from the case histories of patients admitted for treatment on an in-patient basis during the years 1965, 1970, 1975 and 1980 in Grampian Health Board hospitals. The topography of the Grampian Region and a centralised maxillo-facial service in the City
JIICIIL,,\:':J) REGION 4.1%
Other Are3.J of UK (5.S%)
Overseas (I.S%)
Fig. I. Geographical distribution of fracture cases treated during the years 1965, 1970, 1975 and 1980, based on the patient's permanent residence. N=290.
294
BROOK AND WOOD
Table 1. Number of nights spent in hospital for each fracture type
left malar right malar mandible maxilla
Mean no.
Standard deviation
S.E.M.
2.76 4.38 5.45 13.26
2.22 5.82 7.45 12.67
0.245 0.735 0.694 2.43
Maxillary fractures stayed significantly longer than other types. Mandibular fractures stayed significantly longer than left malar. (P < 0.05). At the 90% confidence interval, right malar stayed longer than left malar, mandibles stayed longer than all malars.
THE NO OF FACIAL FRACTURES GRAMPIAN REGiON PER 500000 POPULATION 1965 - 80
120 110 100
90 80 70
60
of Aberdeen has enabled the study of a "closed" population with well-documented records. Fig. 1 indicates the geographic origin of the patients studied. N = 290.
50 40 30
.... :::: ::::: .....
20
Results The results are shown in Figs. 2-7 and Table I.
Discussion During the period of study, the incidence of fractures in the population under consideration had increased by 270%, while the increase in population was only 7%. The majority of this increase is due to an increase in the number of fractures amongst males (Fig. 2). All types of fracture have progressively increased (Fig.. 3), and the proportion of each fracture type has remained fairly constant. By considering each type of fracture in isolation, with regard to its aetiology, some marked differences can be seen. Fractured malars (zygomatic complex) were the most common facial fracture seen,
10
o
;.:.
65
Male •
70
~~;~ .... ~~~~ ....
i....!~!
.... .... .... .:.:
75
80
Year
Female
m
Fig. 2. Number of facial fractures, Grampian Region per 500,000 population 1965-1980.
in contrast to previous surveys9-11 (fractured nasal bones excluded) of past decades, but in agreement with other recent surveys t. When comparing the aetiology and incidence of right and left malar fractures (instead of a random distribution), distinct trends in the pattern of trauma emerged (Fig. 4). It has previously been reported S that malar fractures due to fights, falls and sports show a higher preponderance to
295
FACIAL FRACTURES THl! Olstn,BUTION OF FAAI:YURI::S llY FfMCTUIH;S TyPE FOR THE YEARS 105!i, '~70. 1~75, 1980 60
'il.
60
No of Casr\ each year
No of G'iue~ in ttla.lir.lI\ 10 Ihe IOlal No .... f Cilie, ilith Yllar
60 40
10
6510 75 BO Right Mala,
65 70 15
eo
laft Malat
65 7D 75 80 All Malu
66 70 75
eo
M,Jndi\lll
••11
.,5 10 76 80 Ma~llia
(LeForll
Fig. 3. DistributiDn of fractures by fracture type fDr the years 1965,1970, 1975 and 1980. (a) % Df
cases in relation to the total number of cases each year. (b) Number of cases each year.
affect the left side rather than the right. The present study showed a significant difference (P
FRACTURES LEFT AND RIGHT MALAR DIFFERENCE ACCORDING TO AETIOLOGY
100
90
ill
•
80 70 60 50 40 30 20 10 0
BREAKDOWN OF FRACTURE TYPE BY % AETIOLOGY
Left Malar were more common than Right Malars: Industrial (NS), fall, (NS), assauit' (P < 0.051 Right Malar were more common than Left Malars: Sports (P < 0.1 NS), RTA (NS)
Malar RIL (148) R.t., assaults
Right
sports fall'
Left
industrial oil related
I II iI I
M,ndible
(115)
R.t.a
assaults sports fall' industrial
oil related
.:::::.
·}iIII
~~1~~
·:~I~:
~~~~~l
::::::
Assaults 44
Sports
sports
fall' industrial
Fig. 4. Fractures of right and left malar, dif-
oil ralated
17
Falls 35
(27)
R.t.a assaults
Industrial
No;-
RTA 34
Maxilla
18
ferences according to aetiology. Left malars were more common than right malars, in industrial injuries, falls and significantly so in assaults (P
o
'0
20
30 40 50 Porcentage
60
70
Fig. 5. Breakdown of fracture type by % aetiology. N=290.
296
BROOK AND WOOD
to the face. All the females who received facial fractures in a sporting context did so from an equestrian accident (indicating participation). Fractures of the mandible were the second commonest type of facial fracture in our survey. Blows being sustained during the course of a fight from fists or feet, were the commonest cause of fractured man~ dibles as in other surveys4. 7 • Fig. 5 compares the aetiology of each fracture type, the more severe injuries tending to be caused by the more violent trauma!. Fractures of the maxilla (Le Fort type) formed the smallest group, the main aetiologies being road traffic accidents, "oil-related" industrial accidents and falling from heights. Over the period of study, a marked increase in the number of fractures relating to interpersonal violence was observed, especially since
1970 (Fig. 6); this can now be considered the commonest cause of facial fractures in the Grampian Region. There has also been an increase in the number of and overall % of sports injuries since 1970, although the number of cases in this study is not great. The increase in facial fractures due to assaults, making them the commonest aetiology as in other parts of the UK 8 ; may be due to changes in the structure of the local economy, as well as an increase in violence generally in today's society3. During the period of study, the Grampian Region has become the main UK support aera for a large offshore oil industry. This has lead to a transient population of well paid young men who work for long periods offshore and return to Aberdeen with money to spend and a natural desire to enjoy themselves; their pent-up exuberance
THE DISTRIBUTION OF FRACTURES BY AETIOLOGY FOR THE YEARS 1965, 1970, 1975,1980
... 8-
~
g
40
% No of cases in relation to the total No of cases each year
30
11111 40
1•••
111111.. .. -_
No of cases each year
30
N20
1l 'l5
o 10
z
o
_ _ E::::lffiill
65 70 75 80 RTA
65 70 75 80 Assaults fights
65 70 75 80 Sports
65 70 75 80 Falls
65 70 75 80 Industrial accidents
65 70 75 80 Oil related accidents
Fig. 6. Distribution of fractures by aetiology for the years 1965, 1970, 1975 and 1980. (a) % of cases in
relation to the total number of cases each year. (b) Number of cases each year.
FACIAL FRACTURES NO OF FACIAL FRACTURES
1965, 1970, 1975, 1980 INDICATING THE NO OF CASES WITH MULTIPLE TRAUMA
120
m
•
Total No of cases
No of cases with·multiple concomitant In'juries
Fig. 7. Number of facial fractures 1965, 1970, 1975 and 1980, indicating the number of cases
with concomitant injuries. malar significant. P<0.05.
Difference R/L
may account for some of the increase in assaults. Alcohol plays a prominent rOle in many cases; data on this is difficult to obtain as it is not always the patient who is the imbiber. The increase in sports injuries perhaps reflects an increase in affluence and/or leisure time (Fig. 6).
297
The % of onshore industrial accidents has declined, reflecting a decline in traditional industries and perhaps more stringent safety measures. Injuries due to the developing oil industry have increased with the greater number of offshore employees (100 + in 1965; 16,500+ in 1980) in fIxed installations. Injuries sustained in this fIeld, as well as the more traditional fishing industry, tend to be of a more severe nature and common aetiologies are the whiplash effect of breaking wire ropes/chains hitting the face causing severe compound fractures. Falls from scaffolding also account for offshore injuries. The overall effect of the oil industry in facial trauma without comparison with a similar area not having an offshore industry is difficult to evaluate; a further comparative study needs to be done. It is difficult to estimate the degree of trauma required to cause a particular type of facial injury, as the fracture type depends upon many variable factors; direction of the blow, the individuals bone structure, presence of teeth and atrophy/pathology, etc. However, the length of time the patient is kept in hospital is an indication of the degree of trauma as well as the type of treatment required. As would be expected, maxillary fractures were hospitalised significantly longer than other types (Table 1) and this reflects their more complex treatment and associated injuries (Fig. 7). Mandibular fractures, the majority of which received some form of intermaxillary fixation, were also hospitalised for a longer period than malar fractures. An unexpected difference (90% confidence interval) was noted between right and left malar factures, right malars being hospitalised for longer periods than left malars, despite identical treatment (Gillies temporal elevation 2). This could reflect the cause of injury, those on the right having statistically significantly (P < 0.05) more associated injuries (Fig. 7) which delay discharge from hospital, further emphasis-
298
BROOK AND WOOD
ing the different pattern in aetiology between right and left malar fractures (Fig. 4). Facial trauma in the Grampian Region has increased during the period under study; the reasons for this appear to be an increase in interpersonal violence; prevention in this area is a social responsibility and it is hoped that this article may provoke thought on this matter - sporting activity due to increased leisure time and individual participation. Sports injuries are likely to be more common in the future; an awareness of the risks by participants, the adherance to the rules and safety factors, training and supervision could all help to reduce the incidence of facial injuries in amateur sports for both men and women. The use of mouthguards may help to prevent dental trauma 6 in children, affecting the teeth and alveoli, but will not prevent the high incidence of fractured malars and the more severe facial fractures seen in adult sportsmen. Road traffic accidents account for a high % of facial injuries especially those of a more serious nature. Facial injuries from this cause have continued to increase although to a lesser extent than sports- and assault-related trauma. The introduction of seat belts and in the UK their compulsory use since 1983 is an important aspect of prevention, the effect of which could be evaluated in future years by comparison with data reported here. Motor cycle injuries and pedestrian related trauma are areas where further prevention could be undertaken. Acknowledgement: We thank Mr. P. B. Clarke and Mr. N. W. Kerr, Consultant Oral Surgeons, Aberdeen Royal Infirmary and the Records Department, Aberdeen Royal Infirmary for making the patient histories available.
References 1. ALZELIUS, L. E. & ROSEN, C.: Facial fractures. Int. J. Oral Surg. 1980: 9: 25-32. 2. GILLIES, H. D., KILNER, T. P. & STONE, D.: Fractures of the malar zygomatic compound with a discription of a new X-ray position. Brit. J. Surg. 1927: 14: 651. 3. HAIDAR, Z.: Fractures of the zygomatic complex in the south-east region of Scotland. Brit. J. Oral Slirg. 1977: 15: 265-267. 4. HARNISH, H.: Five-year statistics of jaw fractures. Zalmartl. Prax. 1959: 10: 126. 5. HITCHEN, A. D. & SHUKER, S. T.: Some observations on zygomatic fractures in the eastern region of Scotland. Brit. J. Oral Slirg. 1973: 11: 114-117. 6. JARVINEN, S.: On the causes of traumatic dental injuries with special reference to sports accidents in a sample of Finnish children. Acta Odont. Scaml. 1980: 38: 151-\54. 7. LINDSTROM, D.: A comparative survey of jaw fractures during the years 1948-1958. Dent. Abstr. Chicago 1960: 5: 596. 8. McDADE, A. M., McNICOLL, R. D., W ARDBOOTH, P., HESWORTH, J. C. & Moos, K. F.: The aetiology of maxillofacial injuries with special reference to alcohol abuse. Int. J. Oral SlIrg. 1982: 11: 152-155. 9. ROWE, N. L. & KILLEY, H. C.: Fractures of the facial skeleton Edinburgh: Livingstone, 1969. \0. SCHUCHARDT, K. N., SCI-IWINZER, B., ROTTKE, E. N. & LENTRODI, J.: Ursachen, Hiiugigkeit und Lokalinalian der Frakturen des Gesuchtischadels. Fortichr., Keefer-II. Gesichto-Chis. \966: 11: 1. II. WALDEN, R. H., WOHLGEMUTH, P. R. & FITZGIBBON, J. M.: Fractures of the facial bones. Am. J. Surgery 1956: 92: 915-919.
Address:
I. M. Brook Department of Dental Surgery Charles Clifford Dental Hospital University of Sheffield England