Frenum and Types or Classification of Frenal Attachments in Oral Cavity

Frenum: It is a thin fold of mucous membrane with enclosed muscle fibres that attach the lips to the alveolar mucosa and underlying periosteum.

The Oral cavity has multiple Frenal attachments which are mainly of two types – Frenum and Frenulum (small frenum). In any normal oral cavity there are multiple frena present such as – maxillary labial frenum, mandibular labial frenum and lingual frenum. The Labial frena of the maxilla and mandible provide a junction between the lips to the alveolar mucosa and underlying bone or periosteum while the lingual frenum connects the tongue to the floor of the mouth.

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Classification of Frenal Attachments is based on the extent of attachment of fibres, this classification is done by Placek et al 1974:

• Mucosal attachment: The frenal fibres attachment is positioned at the mucogingival junction
• Gingival attachment: The frenal attachment is positioned or inserted within the attached gingiva
• Papillary attachment: The frenal attachment extends up to the interdental papilla
• Papilla Penetrating attachment: The frenal attachment cross the alveolar process and extend up to the palatine papilla

Apart from the Classification, there are various other variations which are seen with frenum attachments such as Simple frenum with a nodule, simple frenum with an appendix, Bifid labial frenum, Persistent tectolabial frenum, Double frenum and Wider frenum (involves two teeth).

What are the Syndromes which have High Frenum attachment:

• Ehlers-Danlos syndrome (absence of labial and lingual frenum)
• Infantile hypertrophic pyloric stenosis
• Holoprosencephaly
• Ellis-van Creveld syndrome
• Oro-facial-digital syndrome

How to detect abnormal Frenum Attachment?

The basic method to detect an abnormal frenal attachment be it labial or lingual is by applying tension on the frenal attachment and observing the movement of the papillary tip or blanching around the alveolar attachment of the frenum due to ischemia.

What is Ankyloglossia or Tongue Tie:

High Lingual Frenum attachment is also called as Ankyloglossia or tongue-tie and is mostly a congenital anomaly. Tongue-tie is defined by Wallace as “a condition in which the tip of the tongue cannot be protruded beyond the lower incisor teeth because of a short frenulum linguae, often containing scar tissue”.

• In cases of High frenal attachment of Tongue Tie it is suggested to go for Frenectomy.

It results in restricted movements of the tongue leading to difficulty in swallowing and speaking. Difficulty in speech can be identified as caused by tongue-tie when the patient is unable to pronounce the following constants – “s, z, t, d, l, j, zh, ch, th, dg” as these require the tongue tip to touch the tip of the incisors of the hard palate.

Ankyloglossia or tongue-tie is classified into 4 classes by Kotlow based on the length of the tongue from an insertion of lingual frenum at the base of the tongue to the tip of the tongue. (Normal length is 16mm)

• Class I: Mild Ankyloglossia – 12 to 16 mm
• Class II: Moderate Ankyloglossia – 8 to 11 mm
• Class III: Severe Ankyloglossia – 3 to 7 mm
• Class IV: Complete Ankyloglossia – less than 3 mm

To treat any of the above-mentioned frenal attachment abnormalities a procedure called Frenectomy should be performed which have been discussed in detail here – Frenectomy. The details about the various techniques of Frenectomy and when is it needed.