Considerations in Restorative Management and New Oral Findings in a Patient With Congenital Insensitivity to Pain With Anhidrosis

ABSTRACT

Introduction

Congenital Insensitivity to Pain with Anhidrosis (CIPA) is a rare, autosomal recessive genetic condition characterized by an inability to sweat, intellectual disability, a lack of pain sensation and self‐mutilating behaviours. This report describes the dental management and longitudinal oral findings of a child with CIPA, highlighting a restorative approach and novel findings in the permanent dentition.

Introduction

Methods: A 3‐year‐10‐month‐old boy presented with severe early childhood caries, premature exfoliation of primary teeth, traumatic tongue biting and recurrent oral ulceration. Comprehensive dental treatment was performed under general anaesthesia, including restorations and extraction of unrestorable primary teeth.

Introduction

Results: Subsequent follow‐up revealed altered eruption sequence, premature eruption and hypomineralisation and hypoplasia of permanent teeth. At 7‐year‐1‐month, he developed a large palatal ulcer and swelling associated with a recently exfoliated upper left second molar (#65). Wound debridement, excision of malformed upper left second premolar (#25) and restorative treatment of affected permanent teeth were performed under general anaesthesia. Tooth morphology was modified to reduce soft tissue trauma. Healing was observed 1 month post‐operatively.

Introduction

Conclusion: Conservative restorative management may preserve oral function in selected patients with CIPA, while long‐term surveillance is essential because of developmental dental anomalies, altered eruption sequence and recurrent traumatic injury.

1. Introduction

Congenital Insensitivity to Pain with Anhidrosis (CIPA) (OMIM #256800) is a rare, autosomal recessive genetic condition resulting from mutations and polymorphisms in the neurotrophic tyrosine receptor kinase 1 (NTRK1) gene. Characteristics include an inability to sweat, intellectual disability, a lack of pain sensation and self‐mutilating behaviour [1, 2]. Reported oral findings include tongue mutilation, early tooth loss, traumatic biting of the oral mucosa, and occurrences of osteomyelitis [3, 4].

Case reports on patients with CIPA have largely focused on management of the self‐mutilating oral injuries with oral appliances or extractions [1–3, 5, 6]. This report presents the restorative management of a paediatric patient with CIPA and severe early childhood caries, with novel oral findings in the permanent dentition.

2. Case Report

A 3‐year‐10‐month old boy was referred for dental assessment following his genetic diagnosis of CIPA (NTRK1 c.1977G>C p.Lys659Asn, paternally inherited; NTRK1 c.2115G>A p.Trp705Ter, maternally inherited). He also had mild speech and motor delays, oral hypersensitivity (with a retching tendency on toothbrushing and reduced tolerance to solid food), and poor weight gain secondary to his food aversion. His mother's chief complaint was that his lower left second primary molar (#75) had exfoliated two months prior while brushing his teeth, and he had episodes of traumatic tongue biting every few months.

Extraorally, he had sparse hair and scarring on his hands and fingers. He was uncooperative for dental examination and had a severe retching tendency. Intraorally, a healing ulcer was observed on the right lateral border of the tongue. He also had severe early childhood caries and a necrotic upper left first primary molar (#64) with an associated buccal abscess and Grade I mobility. Increased tooth mobility was noted on the lower left first primary molar (#74) and lower right second primary molar (#85). Clinically, there were several missing teeth—upper right central primary incisor (#51) had exfoliated due to grinding between one to two years of age and the lower left and right central and lateral primary incisors (#72, #71, #81, #82) had exfoliated around two years of age.

2.1. Dental Treatment Under General Anaesthesia

At age 4 years 1 month, dental treatment under general anaesthesia (GA) was done. By this time, five additional teeth had exfoliated: three were originally planned for extraction (#74, #84, #85), while two were pristine (#73, #83). Lower left and right first permanent molars (#36, #46) and lower left first premolar (#34) had erupted prematurely (Figure 1). The following dental treatment was rendered:

• ‐#36 glass ionomer restoration to flatten occlusal surface and decrease risk of traumatic biting.
• ‐#55, #65 mineral trioxide aggregate pulpotomy and stainless steel crowns.
• ‐#52 composite strip crown.
• ‐#54, #61, #64 extractions.

FIGURE 1.

Photographs at 4 years 1 month old taken prior to dental rehabilitation. (A) Right buccal mucosa, (B) Frontal view, (C) Left buccal mucosa, (D) Maxillary arch, (E) Mandibular arch.

2.2. Follow‐up Findings

The patient was reviewed at 3–6 month intervals post‐operatively, and his mother reported a decrease in hand‐biting behavior at these reviews. Permanent teeth erupted prematurely with yellow‐brown areas of hypomineralisation, and he had alterations to the eruption sequence, where permanent premolars erupted ahead of central incisors. Recurrent but self‐limiting traumatic ulcers were noted on the tongue and buccal mucosa, often adjacent to erupting teeth. Healing was facilitated by the use of chlorhexidine swabs and reinforcement of good oral hygiene. Regular mouth stretching exercises were taught to preserve mouth opening, given the potential for scarring from frequent self‐mutilation. An orthopantomogram (OPG) was taken at 5 years 3 months of age (13‐months post‐operatively) (Figure 2).

FIGURE 2.

Disturbances in the eruption sequence, delayed dental development, hypodontia, root malformations and taurodontism. OPG taken at (A) 5 years 3 months old, (B) 7 years 1 month old.

At age 7 years 1 month, the patient presented with poor oral intake and persistent fever. On examination, a large ulceration with a yellow pseudomembrane and underlying swelling of the mucosa at the left posterior hard palate region not crossing the midline was noted. Bilateral buccal cheek and lower lip ulcerations were also noted. The upper left second primary molar (#65) had exfoliated a week prior, and an area of necrotic bone was visualised (Figure 3). Localized osteomyelitis was suspected and a viral swab of the ulcer was positive for Herpes Simplex Virus. The patient was subsequently cultured and covered with intravenous Augmentin for four days before being discharged with oral Augmentin for seven days. While the ulcerations subsequently healed over two to three weeks, CBCT confirmed a bony sequestrum along the palatal wall of the #65 socket. Under GA, curettage and removal of the sequestrum and removal of the palatally placed and poorly developedupper left second premolar (#25) was performed. Restorations were placed opportunistically to address the patient's caries risk, enamel defects and minimise risk of damage to soft tissue. These included:

• ‐#16, #14, #26, #36, #34, #42, #44, #46 domed composite restorations.
• ‐#32, #31, #41 composite strip crowns.

FIGURE 3.

Herpes simplex virus infection at 7 years 1 month old (A) Left palatal ulceration, (B) Necrotic bone in #65 socket, with exposure of unerupted #25, (C) Right buccal traumatic ulcer, (D) Lower lip traumatic ulcer, (E) Left buccal traumatic ulcer.

One month post‐operatively, mucosa and alveolar bone healing was observed at the #65 region, and restorations placed to reduce sharp angles and obliterate cuspal inclines further reduced the incidence of traumatic biting. An isolated traumatic ulceration was noted near the erupting upper left first permanent molar (#26). Fibrous bands and scarring on the buccal mucosa were present bilaterally, but his mouth opening remained at three finger breadths (Figure 4).

FIGURE 4.

Two months post‐dental rehabilitation at 7 years 3 months old. (A) Maxillary arch, (B) Left buccal mucosa traumatic ulcer, (C) Right buccal view, (D) Frontal view, (E) Left buccal view, (F) Mandibular arch.

Overall, the patient and his parents felt subjective improvements in dental and general health following treatment. Ongoing monitoring and management will be required for his developing permanent dentition, and traumatic biting.

3. Discussion

A high prevalence of dental caries has been reported among patients with CIPA, with approximately half of them presenting with thermal sensitivity [3]. This suggests that patients with CIPA may retain the ability to perceive discomfort and sensitivity to hot and cold diets from dentine sensitivity, although most are unable to experience painful stimuli from necrotic teeth. Occurrence of acute mandibular osteomyelitis arising from carious teeth without any preceding pain or discomfort have also been documented in CIPA patients [3], underscoring the importance of prompt management of chronic infections. In this case, even though it was uncertain if addressing his caries and infection would improve overall function, the patient's mother preferred to restore and keep his primary teeth where possible, for aesthetic and psychosocial reasons.

In patients with CIPA, GA presents specific challenges such as hyperthermia, risk of aspiration, and autonomic dysfunction which manifest as fluctuations in blood pressure and heart rate (mainly bradycardia). However, given the level of cooperation and extensive treatment needs, GA was deemed necessary and performed with close monitoring of temperature, heart rate [7] and anaesthetic depth [8, 9], as well as the judicious use of opioids [8, 10] both intra‐operatively and post‐operatively. Post‐operatively, short‐term risks include impaired wound healing from self‐mutilation either due to lip or cheek numbness or the presence of foreign sutures and extraction sockets. These were managed by close monitoring post‐operatively by the patient's mother.

Early loss of restored primary teeth before their intended exfoliation can occur, which raises questions about the benefit of restorative interventions. This may not result solely from self‐mutilation but could also stem from defects in cementogenesis and the periodontal ligament associated with the NTRK1 mutation [11]. Retained primary teeth can also lead to recurrent traumatic biting and subsequent peri‐oral soft tissue scarring and fibrosis. Typical strategies to mitigate traumatic biting that have been discussed include elimination of sharp surfaces by grinding or addition of composite restorations; the use of mouth guards, tongue guards, or other appliances, or extraction of the offending tooth [1, 2, 3, 5, 6]. In this case, restorations were placed to round sharp angles and obliterate cuspal inclines, thereby minimising traumatic injuries.

The dental management of patients with CIPA presents significant challenges, primarily due to the need to balance preservation of oral function against the severity of self‐mutilating behaviours. In patients with CIPA, there can be variation in cognitive and developmental abilities ranging from mild learning difficulties to severe cognitive impairments [1, 2, 6, 11], which may have implications on the treatment approach. Previous case reports describing more aggressive approaches [2, 6], such as full mouth dental extractions, often involved patients with more severe developmental or intellectual disabilities or those with extreme self‐mutilating injuries (i.e., deep ulcers on fingers, hands and knees; extensive ulceration of her tongue with a necrotic aspect; self‐extraction of fingernails and digital amputation) [2]. In such patients, behavioural guidance strategies are often unsuccessful. In contrast, our patient exhibited less severe self‐mutilation injuries that were self‐limiting. The lower risk of recurrent trauma in our patient could also be attributed to fewer occluding tooth pairs from premature exfoliation. Importantly, the patient's cognitive capacity allowed for implementation of behavioural guidance which would not have been feasible in patients with more severe intellectual impairments. Chairside counselling and reminders of precipitating factors (i.e., triggers for our patient were erupting teeth and febrile episodes) could also be attempted. In the long term, learning to stop the biting habit and adjusting to teeth in the mouth was crucial for the future retention of this patient's permanent dentition. As such, a restoration‐focused approach may be suitable in patients whose self‐mutilating behaviours are self‐limiting and in those who possess sufficient cognitive capacity to respond to behavioural guidance.

Unlike in the case described by Schalka et al. 2006, where a splint was prescribed to a young patient in the primary dentition [1], the use of a protective splint was contraindicated for our patient as he was in the mixed dentition with non‐optimal oral hygiene maintenance. Developmental anomalies on his permanent teeth further contributed to an increased caries risk.

Delayed development of the permanent teeth and hypodontia are findings that have been sighted in other case reports [11, 12].Clinical and radiographic examination of the patient at five and seven years old showed novel dental findings of disturbances in the eruption sequence of permanent teeth, hypomineralised and hypoplastic permanent teeth, root malformations and taurodontism (Figure 2), which have not been reported previously. These radiographic findings underscore the need for regular close monitoring of the erupting permanent dentition and early individually tailored prevention to delay or prevent the risk of early tooth loss, which could lead to bone atrophy and compromise the long‐term oral health of CIPA patients.

It should be noted that these novel dental findings are derived from a single patient, and as such, their generalisability to other CIPA patients cannot be established. A larger case series or cohort study is required to determine the prevalence and clinical significance of these findings in the wider CIPA population.

Overall, the management of patients with CIPA should be individualised, taking into consideration the severity of self‐mutilating behaviors, cognitive and developmental capacity, and oral health conditions. While a conservative, tooth‐preserving approach was successful in this case, such an approach may not be applicable to all patients and should be carefully adapted to each clinical scenario.

4. Conclusion

Removal of the primary teeth is not the only treatment option to manage caries and traumatic biting, and removal of local irritating factors (e.g., discomfort, sharp uneven surfaces) can be useful and attempted. CIPA patients may also present with disturbances in the eruption sequence of permanent teeth, hypomineralised permanent teeth, hypoplastic permanent teeth, root malformations and taurodontism. These patients would benefit from regular and long‐term follow‐up to reduce the risk of oral complications and maintain oral function.

Author Contributions

Pui Ling Chay is the first author and Melissa Mei‐Yi Khor is the second author. Siew Luan Toh is the corresponding author. Pui Ling Chay and Melissa Mei‐Yi Khor conceived the idea; Pui Ling Chay, Siew Luan Toh, Boon Hui Chan, Vanessa Yan Xiu Kwek, Angela Yun June Tan, Koh Ai Ling collected the data; Pui Ling Chay and Melissa Mei‐Yi led the interpretation and writing; Pui Ling Chay, Melissa Mei‐Yi, Siew Luan Toh, Boon Hui Chan, Vanessa Yan Xiu Kwek, Angela Yun June Tan, Koh Ai Ling revised the manuscript for important intellectual content.

Ethics Statement

KK Women's and Children's Hospital does not require ethical approval for reporting individual cases or case series because the data is anonymised and prior consent has been obtained from the parent

Consent

Written informed consent was taken from the patient's mother regarding the publication of case details and clinical photographs.

Conflicts of Interest

The authors declare no conflict of interest. All authors made substantive contributions to this study and manuscript. All have reviewed the final paper prior to its submission.