Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, representing 5 to 7% of all congenital heart defects (Diaz-Frias et al., 2024)

TOF is the most common outflow tract malformation, grouped with other congenital heart defects (CHD) such as truncus arteriosus and transposition of the great arteries. The condition results from disruptions in key developmental pathways, such as the NOTCH and WNT pathways, during early embryogenesis, leading to abnormal cardiac development.

Approximately 75% to 80% of TOF cases are nonsyndromic, with around 7% involving mutations in genes like NOTCH1, FLT4, and TBX1.

The remaining 20% to 25% of cases are associated with syndromes or chromosomal abnormalities, most commonly trisomy 21 (Down syndrome) and 22q11.2 deletion syndromes, which range from severe forms, like DiGeorge syndrome, which involves dysmorphic features, immune deficiencies, hypocalcemia, and learning disabilities, to less severe forms like velocardiofacial syndrome, which lacks immune deficiencies and hypocalcemia.

Clinical presentation varies based on the severity of the right ventricular outflow tract obstruction (RVOTO), most commonly presenting as a cyanotic neonate.

•Blue or grey skin colour (cyanosis) due to low oxygen levels.

•Shortness of breath and rapid breathing, particularly during feeding or exercise.

•Difficulty gaining weight due to the body's increased metabolic demand.

•Fatigue during play or exercise.

•Irritability and prolonged crying.

•Fainting in severe cases.

•Tet spells, where a baby develops sudden deep blue or grey discolouration of the skin, nails, and lips, typically during episodes of crying, feeding, or distress.

• Surgical Repair

• Primary Surgical Repair: Most children with TOF will undergo surgical repair, typically in the first year of life. This involves closing the ventricular septal defect (VSD) and relieving the obstruction in the pulmonary outflow tract, which improves oxygenation and reduces cyanosis. This surgery allows more oxygen-rich blood to flow from the heart to the lungs.

• Complete Repair: The goal is a complete repair of the defect, which includes patching the VSD and removing the obstruction to the right ventricle outflow tract. This is typically performed as an open-heart procedure.

• Temporary (Palliative) Surgery: In cases where the baby is not strong enough for complete repair, a temporary procedure (such as a shunt) may be done to increase blood flow to the lungs. A common palliative surgery is the Blalock-Taussig shunt, which helps provide more oxygen-rich blood to the body.

• Medical Management Before Surgery

• Prostaglandin Infusion: Prostaglandin E1 (PGE1) can be administered before surgery to maintain ductal patency and ensure pulmonary blood flow in neonates with severe cyanosis.

• Diuretics or Inotropes: If heart function is compromised, medications to manage heart failure symptoms may be given until surgery.

Dental treatment for patients with Tetralogy of Fallot (TOF) requires special considerations.

Dentists are essential in preventing bacterial endocarditis in TOF patients. Invasive dental procedures such as extractions, scaling, oral surgery, and endodontic treatments can introduce bacteria into the bloodstream (bacteremia), particularly when trauma to soft tissue or bone occurs, leading to transient bacteremia. Even minor procedures, such as placing a matrix band, can cause transient bacteremia, which increases the risk of bacterial endocarditis in susceptible patients. To mitigate this risk, prophylactic antibiotics are administered before these dental procedures to prevent bacterial endocarditis, often caused by oral Streptococcus species like S. sanguis and S. mitis.

The rationale for antibiotic prophylaxis is to reduce or eliminate transient bacteremia caused by invasive dental procedures.

Utilization of antibiotic prophylaxis for patients at risk does not provide absolute prevention of infection. Postprocedural symptoms of acute infection usually begin with fever, chills, fast heart rate, fatigue, night sweats, aching joints and muscles, and persistent cough or swelling in the feet, legs, or abdomen. These symptoms may indicate antibiotic failure and the need for further medical evaluation. 

Chronic IE symptoms may include fatigue, mild fever, a moderately fast heart rate, weight loss, sweating, and a low red blood cell count (anaemia).

If a patient Reports a syndrome or medical condition with which the practitioner is unfamiliar, it is appropriate to discuss the risk and susceptibility to bacteremia-induced infections with the child's physician before any invasive dental procedures. 

Antibiotic usage may result in the development of resistant organisms. 

Conservative use of antibiotics helps minimize the risk of developing resistance to current antibiotic regimens.

When scheduling multiple appointments for invasive dental treatment requiring antibiotics, leaving enough time between appointments is crucial. This is to minimize the risk of penicillin-resistant microorganisms developing in the oral cavity, which typically requires intervals of 9 to 14 days. Alternatively, a different class of antibiotics can be prescribed.

• Patients with Tetralogy of Fallot may have increased bleeding tendencies, especially if they are on anticoagulant medications. Cyanotic heart disease can lead to coagulation abnormalities, such as platelet dysfunction or elevated hematocrit levels, which increase the risk of bleeding.

• Preoperative Assessment

• •Medical History Review: Assess the patient's history of bleeding, use of anticoagulant medications, and underlying conditions such as cyanotic congenital heart disease.

• •Consultation with Cardiologist: Coordinate with the patient's cardiologist to evaluate bleeding risks and determine if adjustments to anticoagulation therapy are necessary before the procedure. In some cases, stopping or adjusting anticoagulants may be recommended under the cardiologist’s supervision.

• Local Hemostatic Measures:

• •Pressure Application: Applying firm pressure with sterile gauze to the surgical site can help control bleeding.

• •Hemostatic Agents: Use local hemostatic agents such as:

•Gelfoam or Surgicel (absorbable sponges)

•Topical thrombin

•Collagen plugs for clot formation

•Hemostatic gauze that promotes coagulation

•Sutures: Use sutures to close the wound and provide additional mechanical pressure to prevent postoperative bleeding

•Pharmacological Management

•Tranexamic Acid (TXA): Can be applied locally (mouthwash) or given systemically to promote clot stability by inhibiting fibrinolysis.

Prenatal history:

KC's mother was healthy during pregnancy. She took no medications apart from the standard supplements, and her diet was regular. No special diet was followed.

Natal history:

KC was born full-term. There were no reported neonatal jaundice, birth complications, or injuries; however, he was diagnosed with TOF shortly after berth.

Postnatal history:

KC was breastfed until 18 months and did not use a bottle. His mother described the feeding as on-demand and did not recall regularly wiping his mouth after feedings. After weaning, KC transitioned to drinking from a cup, primarily consuming rooibos tea with added sugar and sugary juices. He also began eating regular family meals.

Medical history:

KC was diagnosed with Tetralogy of Fallot (TOF) shortly after birth and underwent surgical repair at seven months of age. He was on medication for three months post-surgery, which was later discontinued. KC now has annual follow-up visits with his cardiologist. His cardiologist has instructed us to administer prophylactic antibiotics before certain procedures. KC is not allergic to penicillin.

Dental history and oral hygiene practice:

KC's first dental visit was when his cardiologist referred him to the Red Cross Hospital Dental Clinic. During that visit, a brief examination was done. KC brushes his teeth once a day under his mom's supervision. He prefers to brush his teeth independently, does not allow his mother to assist and he does not floss.

KC is a smart child who exhibits signs of anxiety and nervousness. He does not speak English and is quite shy, often keeping to himself. He tends to clench his fists in the dental chair, placing them under his body and stiffening while struggling to keep his head still, indicating discomfort and apprehension.

His facial appearance was symmetrical and normal, with no palpable lymph nodes. The temporomandibular joint was functioning normally, and his muscles were relaxed with no abnormalities.

Morphological examination of the face:

His facial profile is straight, with a mesognathic maxilla and mandible, no accentuated chin fold, and competent lips.

•Molar classification:

•Mesial step on both sides

•The maxillary midline coincides with the midsagittal plane.

•Mandibular midline shifting to the left (1mm) at rest and occlusion.

•Overjet: not applicable

•Overbite: not applicable

•No Crossbite

•No open bite

•Buccal canine bulges: not palpable

•No habit.

KC is in his early mixed dentition. No abnormalities were found in the tongue, frenum, or mucosa. However, visible plaque was observed on his posterior teeth.

55op, which radiography confirmed to be limited to dentin D2, brown spot lesion b 54o, which radiography confirmed to be limited to dentin D1, non-cavitated caries on the buccal surface.

53&63buccal.

52, 51, 61, 62 labial, incisor and palatal.

64om, which radiography confirmed to be limited to dentin D2.

65op, which radiography confirmed to be limited to dentin D2.

75ol, which radiography confirmed to be limited to dentin D1.

74o, which radiography confirmed to be limited to dentin D1.

84o, which radiography confirmed to be limited to dentin D1.

85ol, which radiography confirmed to be limited to dentin D1.

According to Frankl's behaviour rating scale, KC's attitude was classified as negative (Shao et al., 2016).

A combination of techniques was used to manage KC's behaviour, including tell-show-do, distraction, enhancing control, and positive reinforcement. Since KC did not speak English but understood some words, his mother acted as an interpreter to aid communication, ensuring KC's comfort and comprehension throughout the procedures.

Given that this was technically KC's first dental visit, uncertainty about what to expect likely contributed to his anxiety. The tell-show-do technique helped reduce this uncertainty by explaining and demonstrating each step before performing it, which helped put him at ease.

For distraction, we used the TV, as KC enjoyed watching Bluey, and engaged him in conversation with the help of his mother throughout the procedure. This helped divert his attention from discomfort and reduced negative or avoidant behaviours.

We also used the enhancing control technique. KC had been instructed to raise his left arm if he felt uncomfortable or needed a break, and we immediately responded during the procedure. This strategy helped KC feel more in control, reducing his anxiety and fostering a more positive experience.

Throughout the treatment, we closely monitored KC's responses and adjusted our approach to ensure his comfort and cooperation, aiming for a successful and positive dental visit.

Treatment sequence: The treatment plan was organized to progress from the least invasive procedures to more complex treatments. This approach aimed to build KC's trust and cooperation before moving on to more involved treatments. Additionally, procedures that required local anaesthesia and matrix band placement were grouped together, as these necessitated antibiotic prophylaxis.

• Preventive treatment:

1/Oral hygiene education.

2/Fluoride application: 4 times yearly as KC is a child with high caries risk.

3/Diet analysis: A 3-day diary.

4/Caries control: buccal surface of 55,54,64,65,74,75,84,85

• Restorative treatment:

55op, 54o, 53l, 63l, 64od, 65o, 75ob, 74o, 84o, 85ob

•KC's mother insisted on restoring teeth 52, 51, 61, and 62, despite my explaining that these are arrested lesions and that there isn't enough space to properly restore them with strip crowns. She expressed concern about the dark colour of the teeth, noting that KC covers his mouth with his hand when he smiles. She requested that even minimal coverage of the discolouration be done for aesthetic reasons.

Follow-up plan: Monitor those filling with a plan to replace them with permanent adhesive restoration if they fail or when KC's cooperation improves.

1. Introduction of measures to lower KC’s caries risk in the long term: A tooth-friendly diet, effective daily tooth brushing, and adequate fluoride usage.

2. Utilize easy, non-invasive treatments like Interim Therapeutic Restorations (ITR) to help KC become familiar with dental care while keeping the progression of caries at bay.

Rationale:

KC is a high-caries-risk child. Establishing a dental home allows us to focus on treating the underlying disease process rather than simply addressing the outcomes. 

Due to KC’s limited cooperation, he cannot yet tolerate the steps required for adhesive fillings. However, through non-invasive treatments like ITR, we aim to gradually familiarize him with dental care, helping him eventually reach that point.

•Interim Therapeutic Restorations (ITR):

•ITR is suitable for young, uncooperative patients or those with special health care needs, where traditional cavity preparation or restoration must be postponed. ITR is also effective for controlling caries in children with multiple lesions before definitive restorations (AAPD, 2009; APD, 2019).

•Silver Modified Atraumatic Restorative Technique (SMART): (Duggal et al., 2022)

•SMART involves applying 38% silver diamine fluoride (SDF) to a cavity, followed by immediate restoration or sealing with glass ionomer cement (GIC). This approach leverages three key principles:

1. SDF halts caries progression.

2. For deep lesions near the pulp, partial caries removal is performed—particularly in cases where pulp therapy is contraindicated, as with KC.

3. GIC provides a chemically bonded restoration, sealing the cavity and preventing further caries.

First Visit

• 1/ Diagnosis and Treatment plan.

• 2/ OHI&OHD: Active brushing and flossing using a disclosing agent. I instructed KC's mom to brush his teeth and floss as he had not yet developed sufficient manual dexterity to do it himself, and KC agreed to let her brush his teeth till he could write his name and tie his shoelaces.

• 3/ Fluoride varnish application: 5% sodium fluoride varnish (2.26% fluoride, 22,600 ppm F) is the only high-concentration fluoride formulation that can be used in children under six. It effectively arrests and reduces the prevalence of dental caries (AAPD, 2023).

• 4/ Positive Reinforcement: KC was rewarded with a balloon.

• 5/ The next appointment plan was discussed and explained to KC using the Tell-Show-Do technique, ensuring he understood exactly what would happen at the next visit. This approach aims to reduce his anxiety by familiarizing him with the upcoming procedures.

74o, 75o -Vitremer. Same motivation as above

SDF 75.

Silver diamine fluoride (SDF) has been used successfully to stop the progression of carious lesions in people who cannot tolerate invasive treatment, including children, the elderly, people with medical conditions, and people who require additional care and support (Bridge et al., 2021).

Reinforcement of OHI

Positive reinforcement: KC was rewarded with a balloon.

• 1/ Antibiotic Prophylaxis:

KC is not allergic to Penicillin. He weighs 27.3kg.

The Amoxicillin available at the pharmacy is suspension 250mg/5ml.

The recommended dose of Amoxicillin is 50mg/kg

27.3X50=1.365

1.365/250=5.46~5.5 teaspoon.

LA  2% lidocaine containing 1:100,000 epinephrine ¼ ampule infiltration with the STA system to facilitate matrix band placement.

• 2/ 64od, 65o. Vitremer. Same motivation as above.

• 3/ We gave KC a half-hour break and then proceeded with 52, 51, 61, 62. Vitremer.

• 4/ Reiteration of OHI

• 5/ Positive reinforcement: KC was rewarded with a balloon.

The current fillings will be monitored, and if they fail or when KC's cooperation improves, permanent adhesive restorations will be replaced. The next appointment is scheduled for three months. 

In retrospect, I believe we managed KC's behaviour quite well, considering his anxiety and apprehension. Initially, he would clench his fists, tuck them under his body, stiffen in the dental chair, and struggle to keep his head still. Over time, he became more familiar with the dental team. Although he didn’t fully relax, we saw noticeable improvements, particularly in his head movement, even though he continued to show signs of tension by clenching his fists.

Children's behaviour in the dental setting can typically be classified into four categories: (1) cooperative, (2) potentially cooperative, (3) pre-cooperative (lacking cooperative ability), and (4) uncooperative.

In KC’s case, I believe he fell into the pre-cooperative category. Pre-cooperative children are often very young, and communication with them is still developing. Although they may become more cooperative as they mature, they are not yet able to fully understand or handle more complex procedures.

KC's limited English proficiency further complicated communication, which likely hindered his ability to fully understand and cope with the situation. However, with time and continued positive experiences, KC has the potential to become a cooperative patient.

The occlusal-lingual Vitremer filling on tooth 75 failed within four weeks. In retrospect, I believe the failure was due to an inappropriate choice of material. Given the cavity's lingual extension, isolation was compromised, making Vitremer less suitable in this case. A conventional glass ionomer cement (GIC) would have been a better choice, providing better adhesion under suboptimal isolation conditions.

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