Oral injuries: systematic review
Child Protection Evidence is a resource for clinicians across the UK and internationally to inform clinical practice, child protection procedures and professional and expert opinion in the legal system.
Facial and intra-oral trauma has been described in up to 49% of infants and 38% of toddlers who have been physically abused1,2 A torn labial frenum (often referred to as frenulum or phrenum) is widely believed by paediatricians to be pathognomonic of abuse3, and has been described as the most common abusive injury to the mouth4,5.
This systematic review evaluates the scientific literature on abusive and non-abusive oral injuries in children published up until June 2014 and reflects the findings of eligible studies. The review aims to answer two clinical questions:
- Is a torn labial frenum diagnostic of physical child abuse?
- What other intra-oral injuries are caused by physical abuse to children?
- Evidence to date indicates a child with a torn frenum should undergo a full child protection evaluation6 but if no other injuries nor any social concerns are identified, the presence of a torn frenum alone is not diagnostic of physical abuse
- The update in 2014 identified an important study comparing injuries during intubation to abusive injuries. Further literature recently picked up in our searches highlighted the significance of oral injuries as sentinel injuries for severe abuse, present in 11% of cases7, and tribal practices, including removal of the “killer” canine.8
This systematic review evaluates the scientific literature on abusive and non-abusive neurological injuries in children published between 1950 and 2014 and reflects the findings of eligible studies. The review aims to answer two clinical questions:
- Is a torn labial frenum diagnostic of physical child abuse?
- What other intra-oral injuries are caused by physical abuse to children?
A literature search was performed using a number of databases for all original articles and conference abstracts published since 1950. Supplementary search techniques were used to identify further relevant references. See Appendix 1 for full methodology including search strategy and inclusion criteria.
Potentially relevant studies underwent full text screening and critical appraisal. To ensure consistency, ranking was used to indicate the level of confidence that abuse had taken place and also for study types.
The head is the commonest target organ in physical abuse2, with 43% of abusive injuries occurring to the face and neck9 Of these injuries, a torn labial frenum (often inappropriately referred to as frenulum) is frequently described as pathognomonic of child abuse10, yet since it is a trivial oral injury in dental terms we wish to determine the probability that a torn labial frenum is due to physical abuse. Many mechanisms are proposed, including force feeding, twisting and direct blow10,11 We wish to establish the evidence base for this assertion.
- Of 171 studies reviewed (four foreign language articles), 20 studies addressed this question6,12-30
- The majority of children were aged less than five years, where age was given
- No study addressed disabled children
- Accidental frenal injury was explored in a case22
- One study included comparative data23
1.1. Abusive torn frenum
- A prospective study of all children less than 3 years examined within 24 hours of intubation noted that only 1/105 children sustained an oral injury as a consequence of intubation (broken tooth), and torn frena were only observed in 3/14 abused children23
- One child had a lower frenum tear with associated lib abrasion
- Another child had an upper frenum tear with associated swelling to the lips, bruising to the tongue, blood on the teeth, multiple human bites and eyelid bruising
- The third child had a healed frenum scar with associated bruising to the lip, cigarette burns and subconjunctival haemorrhage
- 2/3 children had associated fractures
- These children were aged, 5, 17 and 21 months
- 15 studies addressed abusive torn frenum6,12,13,14,16,17,18,19,20,21,24,26,27,28,29
- Included data on 35 children with an abusive torn frenum
- Approximately 90% were fatally abused (where details given)
- Age: 30 aged 5 years old or less where details are given
- 0-10 years for 5 children27
- 13 children had associated head injury13,14,16,17,18,19,20,21,24,26
- Nine children had fatal head injury13,17,19,20,26,28,29
- Five children had fatal abdominal injuries27
- One fatality had coexistent ano-genital sexual abuse with multiple fractures21
- Torn frenum was first recorded as an abusive injury in 196612
- Two infants (aged six weeks and three months respectively) presented with an unexplained torn frenum and no thorough investigation; they re-presented within three weeks with multiple severe injuries6
- One comparative study of 105 children aged less than 3 years examined within 24 of hours of intubation did not demonstrate any non-abusive torn frenum22
- Four single case studies were conducted, representing four children15,25,27,30
- Two cases occurred as a consequence of intubation; one child aged six months, the other 0-10 years15,27
- 5 year old child fatally injured by an air bag; injuries included torn labial frenum, multiple fractures and intracranial haemorrhages25
- Two and a half year old fell from his bike with intrusion of central upper incisor and torn upper labial frenum; lip injury completely healed within 1 week30
- A study of 324 children aged 0-10 years undergoing resuscitation and dying of natural causes found a single case of torn labial frenum occurred as a consequence of CPR (noted as absent at onset of CPR, confirmed at autopsy27
An injury must never be interpreted in isolation and must always be assessed in the context of medical and social history, developmental stage, explanation given, full clinical examination and relevant investigations. Any unexplained injury that causes concern in a child should be investigated as appropriate:
- Any unexplained torn labial frenum should be fully investigated to exclude the presence of other occult injuries
- There is inadequate evidence to support the view that torn labial frenum is pathognomonic of child abuse, if after a full investigation no occult injuries or social concerns are present in addition to the torn frenum
- Where age is given, the majority of children are less than five years old
- The limited comparative data means that a probability of abuse for torn labial frenum cannot be estimated
- An accidental torn frenum should be a memorable injury for parents, as there is likely to be considerable bloody saliva from the child’s mouth following the injury
- Accidental causes of torn frenum include falls or an accidental blow to the mouth
Further research is needed:
- Prospective comparative studies of torn labial frenum in children, due to abuse or other causes
- Epidemiologic studies of torn frenum in children aged less than five years, including mechanism of injury and co-existent injuries
1.5. Limitations of review findings
- Extremely limited numbers of children represented, and only a single comparative study
- Uncertainty as to frequency of oral examinations performed in child abuse cases
- Possible under-recording of non-abusive torn frenum due to its trivial nature in dental terms
- Lack of epidemiological data on non-abusive torn frenum
- No evidence to support any abusive mechanism of injury other than a direct blow
We aim to document other intra-oral injuries found in physical abuse, as well as their relative frequency. For the purposes of this review, ‘intra-oral’ was defined as between the vermilion borders of the mouth. We did not deal with injuries due to sexual abuse, burns or dental neglect since these will be addressed in separate reviews.
- Of 171 studies reviewed (four foreign language articles), 17 studies addressed this question1,18,23,24,26,28,29,31,32,33,34,35,36,37,38,39,40
- Confirmation of abuse was high; in 12/17 studies the ranking of abuse was 1 or 2
- Age (where provided):
- No study addressed disabled children
- One study addressing this observed no difference in ethnicity to that of the reference population23
- One study examining 105 children aged less than 3 years within 24 hours of intubation demonstrated one broken tooth secondary to intubation, one hard palate injury secondary to foreign body insertion, and 8/14 abused children with oral injuries23
- 6 children sustained lip injuries including swelling, petechiae, bruising or lacerations
- 3 included injury to the tongue, with erythema, laceration and a bite mark
- 3 had torn frena
- All of the above children had coexistent injuries including fractures, intracranial injury, burns, bruises, bites or eye injuries
Details of injuries found (where enumerated) include:
- The commonest recorded injury was laceration or bruising to the lip1,18,24,26,28,29,32,33,34,35,36,37,38,39,40
- The remaining injuries included
- Mucosal lacerations
- Dental trauma (including fractures, intrusion and forced extraction)
- Tongue injuries including an adult bite
- Gingival lesions
- No characteristics of these lesions were specific to an abusive aetiology
Lingual frenum laceration:
Two bizarre case reports of unusual injuries to the mouth include:
A further case report of an unusual injury to the mouth:
- Dummy obstructing airway, forced removal by parents causing laceration of soft palate and pneumothorax31
Presentation with oral bleeding:
- Oral cavity must be examined in all cases of suspected physical abuse
- Paediatricians should be aware of features of primary and secondary dentition, and the likely ages at which they are present
- If any abnormalities are found, seek dental opinion
- Anywhere in the oral cavity can be injured abusively
- The lips are the commonest recorded site of abusive injury (not torn frenum) although it is not always clear how often the oral cavity was examined
Further research is needed:
- Further prospective comparative studies of intra-oral injuries in abused / non-abused children with researchers trained to recognise oral and dental injuries and detailing co-existent injuries and mechanism of injury
- Possible underestimate of intra-oral injuries due to uncertainty as to how many oral examinations were conducted
- Subtle signs of dental injury may be missed by paediatricians
- Be aware of congenital abnormalities of the labial frenum which may be mistaken for a tear41,42,43
- One study recorded the distribution of various types of maxilliary labial frenum attachment44
- Twisting and pulling the child’s lip to cause torn frenum was noted in a single case. This study did not meet our inclusion criteria11
- Comprehensive guidance for dentists and dental hygienists relating to safeguarding children is available online
- Are dentists referring suspected physical abuse cases? Surveys suggest only 8-18% of suspected abuse cases are referred by dentists1,45
- Dental neglect frequently co-exists with oral abuse46
- Injury to alveolar margin and mucosa with later oesophageal atresia47
- UK guidance on child protection referrals for dental practitioners48
- Dental trauma included dental fractures leading to discolouration of teeth and / or inappropriately missing teeth49
- Discolouration may occur with dentinogenesis imperfecta 49 Hypopharyngeal and proximal esophageal rupture with abscess formation50
- Although following the original review we are no longer including single case reports, a recent case study has demonstrated supratonsillar lacerations and scattered facial petechiae in an 11 month old infant51
- 30% of children aged one to six years sustain dental trauma, the peak age being three years53,54,55,56
- Dental trauma is more frequent in boys than girls53,54,55,56
- The commonest accidental injury is laceration to lips and mucosa53,54,55,56
- Dental injuries are more common in56:
- the lower socio-economic group
- obese children
- areas of poor dental care provision (Brazil)
- The infants of mothers with more than eight years’ education sustained more dental injuries during the first year of life53
- A large scale case-control study identified that 11% of children later found to be abused had a previous intra-oral injury which was not acted upon7
Publication arising from oral injuries review:
Maguire SA, Hunter B, Hunter LM, Sibert J, Mann MK, Kemp AM. Diagnosing abuse: A systematic review of torn frenum and intra-oral injuries. Archives of Disease in Childhood. 2007;92(12):1113-1117. Erratum in Archives of Disease in Childhood. 2008;93(5):453.
We performed an all-language literature search of original articles, their references and conference abstracts published since 1950. The initial search strategy was developed across OVID Medline databases using keywords and Medical Subject Headings (MeSH headings) and was modified appropriately to search the remaining bibliographic databases. The search sensitivity was augmented by the use of a range of supplementary ‘snowballing’ techniques including consultation with subject experts and relevant organisations, and hand searching selected websites, non-indexed journals and the references of all full-text articles.
Standardised data extraction and critical appraisal forms were based on criteria defined by the National Health Service’s Centre for Reviews and Dissemination57. We also used a selection of systematic review advisory articles to develop our critical appraisal forms58,59,60,61,62. Articles were independently reviewed by two reviewers. A third review was undertaken to resolve disagreement between the initial reviewers when determining either the evidence type of the article or whether the study met the inclusion criteria. Decisions related to inclusion and exclusion criteria were guided by Cardiff Child Protection Systematic Reviews, who laid out the basic parameters for selecting the studies.
Our panel of reviewers included paediatricians, paediatric dentists, designated and named doctors and specialist nurses in child protection. All reviewers underwent standardised critical appraisal training, based on the Centre for Reviews and Dissemination (CRD) critical appraisal standards 3, and this was supported by a dedicated electronic critical appraisal module.
|Articles of all evidence types||Personal practice|
|English and non-English articles||Review articles|
|Patients between 0-17 years of age||Studies where the population included adults and children but where we could not extract data that applied solely to children|
|Oral injury defined as the vermilion border of the lips to the hypopharynx||Single case reports of abusive torn frenum or intra-oral injury (from 2008)|
|Abusive oral injury||Methodologically flawed papers|
|Torn labial frenum of any aetiology||Rank of abuse 4 (only rank 5 pre-2008)|
|Oral injury due to sexual abuse or intentional thermal injury|
|Complications or outcome of abusive oral injury|
Distinguishing abuse from non-abuse is central to our review questions. As our reviews span more than 40 years, standards for defining abuse have changed markedly. We have devised the following ranking score where “1” indicates the highest level of confidence that abuse has taken place. These rankings are used throughout our systematic reviews (where appropriate).
|Ranking||Criteria used to define abuse|
|1||Abuse confirmed at case conference or civil or criminal court proceedings or admitted by perpetrator|
|2||Abuse confirmed by stated criteria including multidisciplinary assessment|
|3||Abuse defined by stated criteria|
|4||Abuse stated but no supporting detail given|
|Ranking||Criteria used to define accident|
|A1||Independently witnessed accidental cause or forensic recreation of scene|
|A2||By confirmation of organic disease (diagnostic test and / or diagnosis from clinical profile)|
|B1||By multi-disciplinary assessment and child protection clinical investigation|
|B2||Consistent account of accident by the same individual over time|
|B3||By checking either the child abuse register or records of previous abuse|
|C1||Accidental cause / organic diagnosis stated but no detail given|
|C2||No attempt made to exclude abuse / no detail given|
|Ranking of evidence by study type|
|T1||Randomised controlled trial (RCT)|
|T2||Controlled trial (CT)|
|T3||Controlled before-and-after intervention study (CBA)|
|O1||Cohort study / longitudinal study|
|O4||Study using qualitative methods only|
|X||Formal consensus or other professional (expert) opinion (automatic exclusion)|
Definition of levels of evidence and grading practice recommendations (This classification is based on the Bandolier system adapted to include the Centre for Reviews and Dissemination’s Criteria).
|Grade||Level||Type of evidence|
|A||Ia||Evidence obtained from a well designed randomised controlled trial of appropriate size (T1)|
|B||Ib||Evidence obtained from a well designed controlled trial without randomisation (T2, T3)|
|B||IIa||Evidence obtained from a well designed controlled observational study e.g. cohort, case-control or cross-sectional studies. (Also include studies using purely qualitative methods) (O1, O2)|
|C||IIb||Evidence obtained from a well designed uncontrolled observational study (O3, O4)|
|C||III||Evidence obtained from studies that are case series or case studies (O5, O6)|
The below table presents the search terms used in the 2014 Medline database search for all injuries and bites, truncation and wildcard characters were adapted to the different databases where necessary.
|Oral injuries search strategy||Bites search strategy|
Fourteen databases were searched together with hand searching of particular journals and websites. A complete list of the resources searched can be found below.
|Databases||Time period searched|
|ASSIA (Applied Social Sciences Index and Abstracts)||1987 – 2014|
|Child Data||1958 – 2009†|
|CINAHL (Cumulative Index to Nursing and Allied Health Literature)||1982 – 2014|
|Cochrane Central Register of Controlled Trials||1996 – 2014|
|EMBASE||1980 – 2014|
|MEDLINE||1950 – 2014|
|MEDLINE In-Process and Other Non-Indexed Citations||1951 – 2014|
|Open SIGLE (System for Information on Grey Literature in Europe)||1980 – 2005*|
|Pubmed E publications (Epub ahead of print)||2014|
|Scopus||2009 – 2014|
|Social Care online (previously Caredata)||1970 – 2014|
|Trip Plus||1997 – 2005‡|
|Web of Knowledge — ISI Proceedings||1990 – 2014|
|Web of Knowledge — ISI Science Citation Index||1981 – 2014|
|Web of Knowledge — ISI Social Science Citation Index||1981 – 2014|
|* ceased indexing
† institutional access terminated
‡ no yield so ceased searching
|Journals ‘hand searched’||Time period searched|
|Child Abuse and Neglect||1977 – 2014|
|Child Abuse Review||1992 – 2014|
|Websites searched||Date accessed|
|Child Welfare Information Gateway (formerly National
Clearinghouse on Child Abuse and Neglect)
|10 June 2014|
Pre-review screening and critical appraisal
Papers found in the database and hand searches underwent three rounds of screening before they were included in this update. The first round was a title screen where papers that obviously did not meet the inclusion criteria were excluded. The second was an abstract screen where papers that did not meet the inclusion criteria based on the information provided in the abstract were excluded. In this round the pre-review screening form was completed for each paper. These first two stages were carried out by clinical experts. Finally a full text screen with a critical appraisal was carried out by members of the clinical expert sub-committee. Critical appraisal forms were completed for each of the papers reviewed at this stage. Examples of the pre-review screening and critical appraisal forms used in previous reviews are available on request (firstname.lastname@example.org).
|Disclaimer: This is a summary of the systematic review findings up to the date of our most recent literature search. If you have a specific clinical case, we strongly recommend you read all of the relevant references as cited and look for additional material published outside our search dates.
Original reviews and content © Cardiff University, funded by NSPCC
Published by RCPCH July 2017
While the format of each review has been revised to fit the style of the College and amalgamated into a comprehensive document, the content remains unchanged until reviewed and new evidence is identified and added to the evidence-base. Updated content will be indicated on individual review pages.
Skinner AE C.R. 78 Battered children: a retrospective study. ed. London: National Society for the Prevention of Cruelty to Children (NSPCC: Battered Child Research Department); 1969.
Patel F. Artefact in forensic medicine: Childhood iatrogenic oral injury. Police Surgeon 1992; 41: 8-9.
Phillips V.M., Van Der Heyde Y. Oro-facial trauma in child abuse fatalities. S Afr Med J 2006; 96(3): 213-215.
Schuman N.J., Hamilton R.L. Discovery of child abuse with associated dental fracture in a hospital-affiliated clinic: report of a case with a four-year follow-up. Spec Care Dentist 1982; 2(6): 250-251.
Sobel RS K.D. A case of child abuse. In: ed. Clinical management of child abuse. Chicago: Quintessence; 1983. p. 159–164.
VE S. Das verkürzte Zungenbändchen und das hypertrophische Oberlippenbändchen. Zentralblatt für Chirurgie 1969; 17: 570-575.
Donly KJ N.A. Maxillofacial, neck, and dental lesions of child abuse. In: ed. Child Abuse: Medical Diagnosis and Management. Philadelphia: Lea & Febiger; 1994. p. 150-166.
Child protection and the dental team: an introduction to safeguarding children in dental practice.
Polgar A T.S. Chapter 22. Critical evaluation of published research in Introduction to research in the health sciences. . In: ed. Melbourne: Churchill Livingstone; 1995. p.
A schema for evaluating evidence on public health interventions (version 4). Available from link broken
Weaver N., Williams J.L., Weightman A.L., et al. Taking STOX: developing a cross disciplinary methodology for systematic reviews of research on the built environment and the health of the public. J Epidemiol Community Health 2002; 56(1): 48-55.