Ankyloglossia is a congenital condition characterized by a restrictive lingual frenulum that limits the normal range of tongue movement[1]. This anatomical restriction can significantly impair essential oral functions such as swallowing and speaking[2]. The medical concept of ankyloglossia has been recognized since the 1960s. As initially described by Wallace, it was defined as a condition in which the tongue’s frenulum linguae is too short, preventing the tip of the tongue from extending beyond the lower incisors[3].

Despite long-standing debate, the clinical management of ankyloglossia remains highly controversial[1]. There is still no consensus on its precise definition, classification system, diagnostic criteria, or optimal treatment strategy[1].

A notable trend observed over the past two decades is the dramatic increase in infant frenulum diagnoses and subsequent treatments in countries such as the United States, Canada, and Australia, despite declining birth rates[4,5]. This surge is partly attributable to the diverse and inconsistent definitions of the frenulum used by various healthcare providers and researchers[1,6]. The lack of a universal and precise definition of tongue-tie leads to inconsistent diagnostic practices[1]. This inconsistency contributes to inflated reported prevalence rates and the perceived rise in patient numbers. Consequently, surgical interventions have increased, some of which may not be medically justified[1,6,7].

Establishing a universally accepted, function-based definition of tongue-tie is essential. Without such a definition, efforts to standardize diagnosis, accurately assess prevalence, conduct meaningful research, and develop evidence-based guidelines will be significantly hindered. This could result in the overmedicalization of a condition that often resolves naturally or can be managed with non-surgical treatment[1,6].

The reported prevalence of lingual frenulum adhesions varies widely, ranging from 0.1% to 10.7%. This broad range primarily results from the lack of a universally accepted definition and the differing diagnostic criteria used in various studies[1,8].

Interestingly, mild cases of lingual frenulum adhesions often resolve naturally over time. This natural progression helps explain why studies focusing solely on newborns (1.72 - 10.7%) report significantly higher rates than studies examining older children, adolescents, and adults (0.1 - 2.08%)[8,9]. A consistent finding across multiple studies is that ankyloglossia is more common in males, with estimates suggesting it occurs approximately three times more frequently in boys than in girls[10,11].

This condition occurs when the frenulum, located beneath the tongue, fails to fully separate from the tongue before birth. This developmental abnormality may be influenced by genetic factors and often exhibits a familial pattern. As a congenital anomaly, a shortened lingual frenulum may also be associated with other syndromes[12].

The greatest challenge in managing tongue-tie is the lack of universally agreed definitions, classification systems, and standardized diagnostic criteria, which leads to significant variation in treatment approaches[1]. To address this issue, a panel of otolaryngologists published a clinical consensus statement in 2020, defining tongue-tie as “a condition in which restricted tongue mobility is caused by a limited lingual frenulum[1].” The American Academy of Pediatrics (AAP) also recommends that healthcare providers focus on this general definition, emphasizing limited tongue mobility[6].

Ankyloglossia can be classified into two main types.

• Anterior ankyloglossia: This is the classic and more easily identifiable form, characterized by the frenulum attaching to or very near the tip of the tongue, significantly restricting tongue movement[1].

• Posterior ankyloglossia: This term remains highly controversial within the medical community. It generally refers to a frenulum attachment located further back on the ventral surface of the tongue or to submucosal adhesions that are believed to restrict tongue mobility. However, many experts consider what is termed a “posterior frenulum” to be a normal frenulum attachment. Ankyloglossia is an ill-defined term lacking expert consensus and should not be used as a justification for performing surgical procedures on infants[6].

• Recent anatomical studies describe the frenulum not as a simple fibrous band but as a complex fascial fold containing motor and sensory nerve branches. This advanced understanding suggests that there may be no anatomical basis for posterior tongue-tie and that frenotomy, even if seemingly minor, could potentially worsen the condition due to possible nerve involvement[1].

Diagnosis of tongue-tie should primarily focus on demonstrating restricted tongue mobility, which is typically identified when the tongue cannot extend beyond the vermilion border or the lower gum or incisors. A characteristic indented or heart-shaped appearance is often observed when the tongue tip is protruded[1].

A comprehensive medical history and physical examination are essential for an accurate diagnosis. This should include a detailed breastfeeding history, feeding methods, and an assessment of actual milk production[8]. Some healthcare professionals may have limited knowledge of breastfeeding techniques. This underscores the importance of early consultation with a lactation consultant[8]. A collaborative, multidisciplinary approach involving lactation consultants, pediatricians, family physicians, nurses, surgeons, and dentists is crucial for accurate diagnosis and effective management[6,13].

Several assessment tools are used to evaluate tongue-tie; however, their widespread acceptance and validation vary (Table 1)[2,14,15].

There is a gap between the clinical imperative to diagnose tongue-tie based on demonstrable functional impairment and the reality that many existing classification and diagnostic tools, as well as much of the literature, still rely heavily on anatomical appearance[2,14,16]. This can lead to diagnosis and intervention based on perceived anatomical “adhesion” despite the absence of clear functional limitations, resulting in overtreatment[16]. The controversy surrounding posterior tongue-tie exemplifies this issue. The lack of functional criteria fuels debate and may lead to unnecessary procedures[1,2]. This highlights a fundamental flaw in the current diagnostic paradigm, which is an urgent problem. Function-centered diagnostic criteria and assessment tools must be developed and rigorously validated[14,16]. Such changes are essential to ensure that treatment targets only children experiencing actual functional limitations, thereby reducing unnecessary interventions, associated costs, and the risk of potential complications[2,16,17].

When a newborn experiences difficulties with breastfeeding, it is essential to systematically rule out other potential pathologies before assuming the issue is due to tongue-tie[18]. Many symptoms attributed to tongue-tie overlap significantly with those caused by other common breastfeeding problems[8,18].

Key pathological features to consider include the following:

• Craniofacial pathologies, such as a receding jaw (underbite) and cleft palate

• Nasal obstruction: Conditions such as stenosis of the nasal aperture and nasal atresia

• Airway obstruction, such as bilateral vocal cord paralysis or laryngeal flaccidity

• Laryngopharyngeal reflux: a common condition that can mimic or worsen feeding difficulties

• Neurological or cardiovascular disorders that may impair an infant’s feeding ability

It is crucial to gather comprehensive information on various feeding factors. For example, improper feeding posture is often the primary cause of breastfeeding difficulties, rather than issues with the lingual frenulum itself[8,18].

Frenulum adhesion is most commonly associated with breastfeeding and primarily interferes with the process. For infants, breastfeeding complications include difficulty latching, inability to maintain the latch, fussiness during feeding, low milk extraction efficiency, and, consequently, poor weight gain or growth failure[13,18,19]. Infants with tongue-tie struggle to extend their tongue beyond the lower gum line for effective latching and often compensate by pressing the nipple with their jaw[18,20].

Mothers frequently report severe pain during breastfeeding, insufficient milk let-down, or milk remaining in the breast because the baby cannot suck effectively. Persistent nipple pain affects up to 80% of these women, and approximately 25% consider switching to bottle feeding due to extreme pain or difficulty, even after six weeks postpartum[20,21].

Tongue-tie release can offer short-term benefits, such as reducing nipple pain for the mother. Improvements in breastfeeding efficiency may also be observed. However, there is currently no definitive evidence that it extends the overall duration of breastfeeding. Methodological limitations in existing studies, including small sample sizes and lack of blinding, make it difficult to draw definitive conclusions about long-term breastfeeding success. For example, the Cochrane Collaboration’s 2017 review concluded that frenotomy reduced maternal nipple pain in the short term but did not consistently improve infant breastfeeding outcomes[13,18].

Symptoms linked to the lingual frenulum are part of a connected physiological system, not isolated local problems. Tongue movement limitations may lead to compensatory changes and secondary effects in respiratory, digestive, musculoskeletal, language, and emotional development. Research suggests the oral cavity’s function is deeply integrated with systemic health[22,23]. Therefore, a holistic, multidisciplinary approach for diagnosis and management considering overall quality of life is essential. Early, effective intervention might help prevent additional complications, but further study is needed to confirm this[21,22].

Consulting a lactation consultant is strongly recommended before considering surgical intervention, especially when breastfeeding difficulties are present. It is often observed that the primary cause of breastfeeding issues is an improper feeding position rather than the frenulum itself[8,30]. Because this is a complex issue, a thorough breastfeeding assessment by a comprehensive, multidisciplinary team is necessary. Ideally, this team should include breastfeeding specialists, lactation consultants, and pediatricians to provide a holistic evaluation and management plan[30].

For children experiencing language difficulties, consultation with a speech-language pathologist is essential. This is especially important for issues related to bottle feeding or articulation exercises. The speech therapist may also refer the patient to a multidisciplinary team if the problem appears more complex. Some studies suggest that language problems associated with ankyloglossia can be effectively addressed and resolved through professional speech therapy alone, without the need for frenotomy[23,24,31].

Frenectomy is the most common surgical procedure used to correct tongue-tie. This procedure can be performed using traditional methods, typically involving scissors to release the lingual frenulum. Alternatively, laser frenectomy is also an option and is often described as safe, simple, and comfortable. Although studies comparing various frenotomy techniques exist, current research does not indicate that any one method is definitively superior to the others[32].

Surgical intervention should be considered a reasonable option for symptomatic tongue-tie, but only after thoroughly evaluating and, if possible, addressing other potential causes of breastfeeding difficulties. It is important that the frenotomy be performed by a trained specialist with extensive experience in the medical care of newborns and infants. Furthermore, the process should include a comprehensive discussion of all possible alternatives, the potential risks and benefits of the proposed procedure, and various pain management options[32].

Frenectomy is generally considered a safe procedure. Minor bleeding is the most common complication. However, more serious complications have been reported in several studies[32,35].

• Delayed Differential Diagnosis: Frenectomy may postpone the identification of more serious underlying causes of malnutrition, such as congenital heart disease or metabolic disorders[35].

• Bleeding: Cases of severe bleeding and hemorrhagic shock have been reported.

• Infectious diseases: Submandibular abscess, Ludwig’s angina, and others.

• Respiratory disorders: Apnea and acute life-threatening events.

• Refusal to eat: Potential for prolonged refusal of oral intake after the procedure.

• Discomfort: Potential refusal to breastfeed due to pain[8].

The challenges associated with effective breastfeeding and the broad, multifaceted impact of tongue-tie highlight the inherent complexity of this condition. A multidisciplinary approach is essential for achieving successful outcomes. This collaborative model ideally includes lactation consultants, pediatricians, family physicians, nurses, surgeons, lactation therapists, and dentists working together to provide comprehensive care and support shared decision-making with families[30].

Although research and publications on tongue-tie and frenotomy have risen globally, robust scientific evidence has not kept pace with clinical activity. Most studies lack quality design, including randomized controlled trials and reliable outcome measures, leading to weak evidence-based guidelines. Methodological flaws like small sample sizes and inconsistent blinding are common, and objective data on outcomes such as breastfeeding duration and infant growth are scarce. Clinical practice and treatment rates are growing faster than scientific validation, raising concerns about overtreatment and resource misuse, with potential risks to patients if long-term efficacy remains uncertain[34,36].

Key controversies in the study and practice of adhesions revolve around several core areas:

• Definition and Diagnostic Criteria: The absence of standardized definitions and universally accepted diagnostic criteria continues to hinder consistent diagnosis and research[36].

• Posterior Tongue Adhesions: The existence and clinical significance of posterior tongue adhesions remain highly contentious. Many experts consider them normal anatomical variations that do not require intervention[1,37].

• Optimal Timing and Intervention Methods: There is no clear consensus on the ideal age for surgery, nor is there agreement on whether conventional frenectomy or laser surgery yields superior outcomes[32].

• Treatment vs. Spontaneous Resolution: The degree to which observed improvements can be attributed to frenectomy, as opposed to natural resolution in mild cases or the advantages of non-surgical feeding support, remains unclear[13,18,36].

• Long-Term Outcomes: The long-term efficacy of frenectomy beyond the immediate relief of breastfeeding discomfort remains insufficiently explored[34,36].

Neurological disorders can significantly impair tongue movement by affecting the nerves that control the tongue muscles, the brain regions responsible for planning and executing speech and swallowing, or the overall motor control system[39,40]. Restrictions in tongue movement often serve as key indicators of various neurological disorders that impact not only oral function but also systemic health, including respiratory function and overall developmental processes[41].

Restricted tongue movement may result from muscle weakness (hypotonia), stiffness (myotonia), or abnormal size (macroglossia), not solely from physical causes like lingual ties[45].

This category includes primary structural abnormalities such as a small jaw, tongue hypertrophy, or skeletal growth anomalies, which may lead to a range of secondary functional problems affecting breathing, feeding, speech, dental health, and even psychosocial development. Addressing the underlying structural issue is often essential to resolving these functional limitations, rather than treating the symptoms.

Tongue movement restrictions can result not only from congenital or developmental issues but also from external factors, including iatrogenic causes or injuries. Medical interventions can unintentionally lead to tongue movement limitations, emphasizing the importance for healthcare professionals to be aware of potential iatrogenic complications.

General oral motor dysfunction refers to difficulties in the movement and coordination of muscles within the mouth, face, and throat, including the lips, tongue, jaw, and palate. This condition can result from reduced muscle tone, oral sensory dysfunction (either hyposensitivity or hypersensitivity), or movement imbalances. The causes of such dysfunction are often unclear, arising from the complex interaction of multiple factors. When the cause is uncertain, a multidisciplinary team approach is essential to identify the intricate interplay of sensory, motor, developmental, and behavioral factors[41,44,60].

Causes may be related to neurological disorders such as prematurity, underdeveloped oral muscles, cerebral palsy, or other neuromuscular conditions. Developmental delays and low muscle tone are also contributing factors. Diagnosis involves an oral sensory-motor assessment conducted by a speech-language pathologist. This assessment includes detailed observation of facial structure, muscle strength, range of motion, sensory responses, and feeding behaviors. Specialized tools, such as the Pediatric Eating Assessment Tool (PediEAT) or the Schedule for Oral Motor Assessment (SOMA), may be utilized. Treatment focuses on oral motor therapy and speech therapy to improve oral muscle strength, coordination, and control. Therapeutic activities may include tongue exercises, bubble blowing, drinking through a straw, and oral sensory stimulation[61,62].

Tongue thrusting refers to the action of pushing the tongue forward against or between the teeth during swallowing or speaking. It is associated with normal swallowing patterns in infancy and usually resolves as the child grows[63].

However, persistent tongue thrusting can result from prolonged thumb or finger sucking, extended pacifier use, enlarged tonsils or adenoids, or upper airway obstruction caused by allergies. Reduced strength or tone in the oral muscles, genetic factors, and the persistence of the infant’s swallowing reflex can also contribute[58]. Tongue thrusting may cause or exacerbate an open bite. Articulation disorders affecting sounds such as /s/, /z/, /t/, /d/, /n/, and /l/ are also common. Diagnosis is typically made through clinical observation by a speech-language pathologist, often in collaboration with an orthodontist. A physician’s airway examination is also important to rule out airway obstruction as a contributing factor[63].

Treatment includes orofacial myofunctional therapy and speech therapy, aiming to establish a normal oral resting posture in which the tip of the tongue rests on the alveolar ridge and to ensure proper tongue movement during swallowing. Exercises include lip closure, tongue elevation, and training in specific tongue positions[63].

Children with overall developmental delays may also show delays in acquiring the fine motor control and coordination skills required for complex oral movements. This indicates broader neurological immaturity rather than a specific oral pathology[64].

Symptoms resemble those observed in general oral motor dysfunction, including difficulties during feeding developmental stages (e.g., transitioning to solid foods), delayed language development, and challenges with oral hygiene. Diagnosis requires a comprehensive developmental assessment, incorporating a detailed evaluation of oral motor skills. Early intervention through occupational and speech therapy is essential, emphasizing the strengthening and coordination of oral muscles via play-based activities and targeted exercises[64,65].

A comprehensive history, including prenatal and birth details, family history of similar conditions, growth patterns, comorbidities, and allergies, is essential. The physical examination should encompass an oral assessment to evaluate oral reflexes and a perioral examination to assess symmetry, sensation, strength, tone, range, speed of movement, and coordination of the lips, jaw, tongue, palate, pharynx, and larynx. Observing infant-caregiver interactions, conducting developmental motor assessments, and evaluating respiratory status, alertness, and self-regulatory behaviors are also critical. A detailed feeding history and observation of feeding patterns, including latching, sucking, chewing, swallowing, meal duration, and signs of distress such as coughing, choking, gagging, hoarseness, or food refusal provide valuable insights into functional limitations[67].

When differentiating from lingual frenulum issues, clinicians must specifically determine whether a restrictive lingual frenulum is the primary limiting factor. If typical symptoms of lingual frenulum syndrome, such as a dimpled or heart-shaped tongue tip or inability to extend the tongue beyond the lower incisors, are not present, other causes should be considered for accurate diagnosis[16].

Instrumental evaluation is essential for objectively capturing and visualizing the biomechanical processes involved in swallowing. It is also crucial for assessing structures that are not easily visible during a clinical examination.

• Video Fluoroscopic Swallowing Study (VFSS)/Modified Barium Swallow Study (MBSS): This X-ray examination visualizes swallowing movements in real time using various food consistencies and evaluates oral, pharyngeal, and esophageal function. It is highly effective for identifying anatomical or physiological abnormalities, esophageal bolus flow issues, and the presence of aspiration. However, due to radiation exposure and the examination environment, it can be challenging for uncooperative children[68,69].

• Fiberoptic Endoscopic Evaluation of Swallowing (FEES): This procedure involves inserting a flexible endoscope through the nose to directly visualize swallowing function. It is radiation-free and portable. FEES assesses structural integrity, the presence of secretions, and the patient’s response to food and liquids[70].

• Ultrasound Examination: This non-invasive technique allows dynamic observation of the oral phase of swallowing by monitoring the movements of the tongue and hyoid bone[71].

• High-resolution manometry: This technique measures pressure within the pharynx and esophagus, providing objective data on muscle contractions during swallowing[72].

Several specialized tools are available to objectively assess oral motor function.

• Schedule for Oral Motor Assessment (SOMA): This observation-based assessment is designed for infants and toddlers aged 0 to 2 years. It is a reliable method for evaluating oral motor function in children with swallowing difficulties and is especially useful for those who may be uncooperative during a Video Fluoroscopic Swallowing Study (VFSS). SOMA evaluates a child’s ability to manipulate various food textures over approximately 20 minutes[62].

• Dysphagia Disorders Survey (DDS): An observation-based assessment tool designed for children with developmental disabilities aged 2 to 21 years. It is recognized for its high reliability and validity in identifying and characterizing swallowing and feeding disorders[73].

• Pediatric Eating Assessment Tool (PediEAT): A parent-reported instrument designed to measure feeding problem symptoms in children aged 6 months to 7 years. Age-specific screening tools are provided to facilitate initial evaluation[61].

• Oral Motor Measurement Scale (OMMS): Developed by the Kennedy Krieger Institute, the OMMS quantifies oral motor and swallowing functions during inpatient rehabilitation for children aged 2 years through adolescence following acquired or traumatic brain injury. It assesses solid and liquid food intake, chewing patterns, tongue lateralization, secretion management, and functional eating speed[67].

• Tongue-o-meter: A biofeedback device that objectively measures tongue strength and endurance. It is useful both for the initial assessment to determine whether tongue weakness is causing dysphagia and for guiding and monitoring progress in tongue-strengthening exercises[74,75].

Speech-language pathologists play a central role in assessing and treating oral motor dysfunction, including restrictions in tongue movement. Treatment focuses on improving the strength, coordination, and control of the muscles involved in eating, drinking, and speaking[44,63].

• Oral Motor Exercises: Targeted exercises designed to strengthen muscle strength and coordination, such as pressing the tongue against a spoon or tongue depressor and curling the tongue toward the palate. Playbased therapy for younger children often incorporates activities like blowing bubbles, drinking through a straw, whistling, and pursing the lips[23,44,63].

• Sensory Stimulation Techniques: Explore a variety of food textures and oral sensations to enhance oral sensory awareness and tolerance, particularly in children with hypersensitivity or hyposensitivity[78].

• Swallowing Strategies: Collaborate with children to develop more effective chewing and swallowing techniques and specific maneuvers to enhance the safety and efficiency of swallowing[44].

• Dietary Modifications: Adjust the viscosity, texture, temperature, or portion size of foods and liquids to ensure safe swallowing and adequate nutritional intake[44].

• Adaptive Devices: Utilizing specialized equipment and tools to control bolus size or liquid flow rate, thereby enhancing independence and improving swallowing safety[44].

• Oral-Facial Muscle Function Therapy: This therapy is especially beneficial for conditions like tongue thrusting. It focuses on establishing a normal oral resting position, with the tongue tip placed against the alveolar ridge, and promoting proper tongue movement during swallowing. The therapy typically includes targeted tongue positioning exercises and activities designed to enhance lip mobility[23,63].

Surgical intervention is performed based on the underlying cause of restricted tongue movement.

• Neurological Conditions: For conditions such as hypoglossal nerve palsy, treatment primarily focuses on addressing the underlying cause, such as managing tumors or treating infections. In cases of stroke or brain injury, rehabilitation is essential and is often combined with speech therapy[76].

• Muscular and Genetic Disorders: The focus is often on supportive care for feeding and breathing difficulties, including physical therapy and sensory stimulation programs for congenital myopathies. For syndromes such as macroglossia, surgical reduction of tongue size may be considered if symptoms are severe and cause significant functional impairment. Severe feeding disorders may require nutritional support, including tube feeding[46].

• Structural and Anatomical Abnormalities: For mandibular fractures, posture modifications (e.g., prone sleeping position) or respiratory support (e.g., breathing tubes) may be provided until jaw growth stabilizes. Oral tumors and cysts are often surgically removed if they interfere with function or cause discomfort. Craniofacial abnormalities, such as cleft palate, typically require surgical correction by a multidisciplinary team[79].

• Acquired and Iatrogenic Causes: Following postoperative complications or traumatic injury, careful observation until nerve recovery occurs may be necessary, followed by rehabilitation therapy. Management of the side effects of radiation therapy focuses on symptom control (pain, xerostomia) and swallowing therapy[76].