Palatal sensation is important for articulation, feeding, and swallowing. However, palatal sensation in patients with cleft palate (CP) after palatoplasty has been investigated only inadequately because of the complexity and high costs of objective evaluation. This study compared the somatosensory evoked magnetic fields (SEFs) induced by electrical stimulation of the palates of patients with CP after palatoplasty and the palatal sensory thresholds (PSTs) of the stimulation with those of healthy (control) subjects. The CP group comprised 12 patients with unilateral cleft lip and palate (UCLP). The control group comprised 31 control subjects. No significant difference in intensity was found between them. Nevertheless, the PSTs in the UCLP group were significantly higher than those in the control group at all sites (p < 0.05). We infer that the electrical signals transmitted from palatal sensory receptors of patients with CP might be amplified by a compensation mechanism in the central nervous system. SEFs provide an effective method for objective evaluation of palatal sensation in patients with CP after palatoplasty. Evaluation of SEFs during palatal sensory stimulation in patients with CP after palatoplasty might lead to better corrective surgical methods that also preserve palatal sensation.

Background Cleft lip is the most common congenital anomaly worldwide. Nevertheless, lip somatosensory characteristics of patients with cleft lip after cheiloplasty have not yet been determined. The present study used magnetoencephalography to objectively evaluate the lip sensation in patients with unilateral cleft lip to establish a new objective evaluation method. Methods Participants were 15 patients with unilateral cleft lip after cheiloplasty (UCL group), and 30 healthy young subjects (control group). Five points of the upper and lower lips were stimulated electrically to measure somatosensory evoked magnetic fields (SEFs). The sources of the magnetic fields were modeled as single equivalent current dipoles (ECDs). ECDs located on the central sulcus by superimposition on magnetic resonance images were analyzed. Latency and intensity at 50–75 ms (cP60m) observed in the UCL group were compared with those in the control group. Thresholds of tactile stimuli in both groups were obtained using Semmes–Weinstein monofilaments for subjective sensory evaluation. Results No significant difference was found in the intensity of the cP60m or subjective evaluation between the groups. However, the latency of the cP60m was significantly longer in the upper lip of the UCL group than in the control group. Conclusions SEFs showed a difference in lip sensation between the UCL group and the control group, suggesting that longer latency might be caused by the effects of surgical scarring on the neurotransmission pathway. These results suggest SEFs as useful for the objective evaluation of lip sensations. This study might improve future surgical procedures and lip functions of patients with cleft lip.

Introduction Bone-anchored maxillary protraction (BAMP) was devised recently as a method of direct maxillary protraction using anchor plates implanted in the maxilla and mandible without involving the teeth. Although several reports have described orthognathic effects of BAMP on patients with cleft lip and palate (CLP) with skeletal crossbite, none has described a study of Japanese patients with CLP or of BAMP treatment effects on speech in patients with CLP. This study, by performing BAMP treatment, and by evaluating speech function and skeletal and soft tissues, is intended to clarify BAMP efficacy and safety for patients with unilateral CLP (UCLP) who have skeletal crossbite. Methods and analysis This single-arm, open-label, non-randomised prospective study examines 20 patients with UCLP with skeletal crossbite (Wits appraisal ≤−5.0 mm). These 10–15 year-old participants had already undergone cheiloplasty, palatoplasty and bone grafting. The anchor plates are implanted in the zygomatic process in the maxilla and in the anterior part of the mandible. Two weeks after anchor plate implantation, maxillary protraction is started using elastics. Protraction is performed at 150 g per side at the start of protraction, 200 g per side from 1 month after the start of protraction and 250 g per side from 3 months after the start of protraction. The treatment period will be approximately 1½ years. Pretreatment and post-treatment, cephalometric analysis, speech evaluation, nasopharyngeal closure function evaluation and facial soft tissue evaluation will be performed to ascertain the effects of BAMP on patients with UCLP. Ethics and dissemination Ethical approval for this study has been received from Tohoku Certificated Review Board of Tohoku University, Japan, CRB2200003. The approval number is 2021-34-2. The results of this research shall be presented at domestic and international academic conferences, and be published to peer-reviewed journals. Trial registration number jRCTs022210007.

The periodontal ligaments are very important sensory organ for our daily life such as perception of food size or hardness, determination of jaw position, and adjustment of masticatory strength. The sensory properties of the periodontal ligament, especially those of the maxillary and mandibular molars, have not yet been fully investigated. Somatosensory evoked magnetic fields (SEFs) can be measured and evaluated for latency and intensity to determine the sensory transmission characteristics of each body parts. However, previous reports on SEFs in the oral region have only reported differences in upper and lower gingival and lip sensations. In this study, the aim was to clarify these sensory characteristics by measuring SEFs during mechanical stimulation of the periodontal ligament in the maxillary and mandibular first molars. Somatosensory evoked magnetic fields were measured in the contralateral hemispheres of 33 healthy volunteers. Mechanical stimulation of the maxillary and mandibular right first molars, and the left wrist was performed with a specific handmade tool. The first peak latency for the mandibular first molars was 41.7 ± 5.70 ms (mean ± SD), significantly shorter than that for the maxillary first molars at 47.7 ± 7.36 ms. The peak intensity for the mandibular first molars was 13.9 ± 6.06 nAm, significantly larger than that for the maxillary first molars at 7.63 ± 3.55 nAm. The locations in the contralateral hemispheres showed no significant difference between the maxillary first molars and mandibular first molars. These locations were more anteroinferior and exterior than that of the wrist, as suggested by the brain homunculus. Neural signals from the mandibular periodontal ligaments pass faster and more intensely to the central nervous system than those from the maxillary periodontal ligaments, and may preferentially participate in adjustment of the occlusal force and the occlusal position.