OBJECTIVE: The incorporation of retromolar bone grafts used for alveolar ridge augmentation is not well understood. This prospective observational study aims to supply histomorphometrical data from bone graft biopsies taken at the time of retrieval and after a 3-month healing period using patient-matched biopsies.
METHODS: In 17 patients, trephine biopsies of the graft were acquired at the time of graft retrieval and after a 3-month healing period. The biopsies were compared histomorphometrically regarding the number of osteocytes, appearance of osteocyte lacunae, quantity, surface area, and activity of the Haversian canals.
RESULTS: All grafts appeared clinically stable after screw removal and 17 implants were placed. Histomorphometric analysis revealed no significant difference in the number of osteocytes (p = .413), osteocyte lacunae (p = .611), the ratio of filled/empty osteocyte lacunae (p = .467) and active Haversian canals (p = .495) between the biopsies retrieved after a 3-months healing period with those at the time of grafting. The only significant difference was noted in the mean surface area of the Haversian canals (p = .002). Specifically, the grafts post 3-month healing showed a significantly larger mean area (0.069 mm2) compared to the time of grafting (0.029 mm2).
CONCLUSIONS: This study demonstrates, compared to other data, a high rate of vital structures in retromolar bone block grafts after 3 months of healing, exhibiting the same histological features in comparison to the biopsies from the native alveolar ridge. Standard histomorphometrical parameters, e.g., the amount of filled or empty osteocyte lacunae for the description of the vitality of the graft need to be reappraised.

Inflammatory myofibroblastic tumor (IMT) of the oral cavity is an extremely rare finding. The etiology and pathogenesis of IMT is controversial and unclear. The tumor requires complete surgical excision and continuous monitoring of clinical consequences. The present article describes the clinical, histological, operative and immunohistochemical features of a case of IMT in the mandibular retromolar region of an 8-year-old male. Histologically, the lesion shows myofibroblastic spindle cell proliferations with infiltrative margins in an inflammatory background. Immunohistochemically, the myofibroblastic spindle cells in the present case were positive for α-smooth muscle actin and CD68 due to which the diagnosis of IMT was confirmed.

OBJECTIVE: Difficult airway situations, such as trismus and neck rigidity, may prohibit standard midline orotracheal intubation. An alternative route of intubation from the retromolar space using a fiberoptic scope or rigid intubation stylet has been reported. There is no study investigating the applicability of retromolar intubation using a video intubating stylet. This study comparatively analyzed difficult airway management using a video intubating stylet in the retromolar and standard midline approaches.
METHODS: A randomized crossover manikin study was conducted between January 2021 and June 2021 at a tertiary teaching hospital. Thirty-six emergency medicine residents and attending physicians were enrolled, and all participated in an educational course regarding video intubating stylet in standard midline and retromolar approaches. Then, they performed both intubation approaches in a randomized order on a manikin seven times with different airway settings each time. The duration of successful intubation, first attempt success rate, overall success rate, number of attempts, and self-reported difficulty were recorded and compared.
RESULTS: Thirty-six emergency physicians were included in the study. Compared with the standard midline approach, the use of the retromolar approach significantly reduced the duration of successful intubation in difficult airway scenarios such as limited mouth opening and neck rigidity with (44.77 [28.58-63.65] vs. 120 [93.86-120] s, p < 0.001) and without tongue edema (31.5 [22.57-57.74] vs. 44.72 [36.23-65.34] s, p = 0.012). Furthermore, the retromolar approach increased the first attempt success rate in scenarios of limited mouth opening and neck rigidity with (91.67% vs. 16.67%, p < 0.001) and without (97.22% vs. 72.22%, p = 0.012) tongue edema. The self-reported difficulty was also significantly lower with the retromolar approach than with the standard approach in the above two scenarios.
CONCLUSIONS: The retromolar approach for intubation using a video intubating stylet may be a promising choice for selected patients with a combination of difficult airway features such as limited mouth opening, neck rigidity, and edematous tongue.

We have characterized a recently rediscovered chemosensory structure at the rear of the mandibular mucosa in the mouse oral cavity originally reported in the 1980s. This consists of unorganized taste buds, not contained within troughs, associated with the ducts of an underlying minor salivary gland. Using whole-mount preparations of transgenic mice expressing green fluorescent protein under the promoter of taste-signaling-specific genes, we determined that the structure contains taste bud clusters and salivary gland orifices at the rear of each mandible, distal to the last molar and anterior to the ascending ramus. Immunohistochemical analysis shows in the retromolar taste buds expression of the taste receptors Tas2R131 and T1R3 and taste cascade molecules TrpM5, PLCβ2, and GNAT3, consistent with type II taste cells, and expression of GAD1, consistent with type III taste cells. Furthermore, the neuronal marker, calcitonin gene-related peptide, in retromolar mucosa tissue wrapping around TrpM5+ taste buds was observed. RT-PCR showed that retromolar taste buds express all 3 mouse tas1r genes, 28 of the 35 tas2r genes, and taste transduction signaling genes gnat3, plcb2, and trpm5, making the retromolar taste buds similar to other lingual and palate taste buds. Finally, histochemistry demonstrated that the mandibular retromolar secretory gland is a minor salivary gland of mucous type. The mandibular retromolar taste structure may thus play a role in taste sensation and represent a potential novel pharmacological target for taste disorders.

The retromolar foramina (RMF) and the retromolar canal (RMC) are anatomic variants in the mandible located distally to the last molar. The retromolar nerve, which runs through the RMC, is a type 1 bifidity of the mandibular canal. The investigations of the RMF and RMC have been performed by dry mandible studies, the panoramic radiograph (PAN), computed tomography (CT), and the cone beam computed tomography (CBCT) studies. The CBCT has been shown to be the superior method for visualizing the RMF and RMC. There is wide variation in the frequency, location, diameter, and distance of the canal in different individuals. Overall, there is no significant difference in the frequency of the canal in the mandible between sexes or sides of the mandible. The peak incidence of the RMF may occur in adolescence. The RMC is significant due to the neurovascular bundle which runs through it. Injury to this neurovascular bundle during surgical procedures, such as third molar extraction, implant placement, or split sagittal osteotomy, may lead to paresthesia, excessive bleeding, or traumatic neuroma. The presence of RMC may also lead to insufficient anesthesia in the mandible which may be overcome with alternative anesthetic techniques.

Basal cell adenoma is a rare benign salivary gland neoplasm. The most common location is in parotid region. Clinically, gradual growth and firm consistency are seen. They account for 1 to 3% among all salivary gland neoplasms. Prominent basaloid cells with cluster of isomorphic cells and interspersed trabeculae are present histopathologically. In this article, we present a rare case of basal cell adenoma of retromolar region from minor salivary gland origin.

OBJECTIVE: This study aimed to determine the effectiveness, safety, and oral intubation time (IT) using a retromolar Bonfils fiberoptic scope compared with a conventional Macintosh laryngoscope.
METHODS: Sixty patients (16-60 years old, American Society of Anesthesiology I/II) scheduled for general anesthesia for elective ear-nose-throat and plastic surgery were randomly divided into a Bonfils group (Group B, n = 30) and a Macintosh group (Group M, n = 30). Exclusion criteria included Mallampati IV, thyromental distance ≤4 cm, mouth <4 cm, cervical spine problems, body mass index >35, sleep apnea, reflux esophagitis, coronary artery disease, intracranial vascular malformation, elevated intracranial pressure, bleeding disorders, allergies to planned drugs, and patient refusal. Mallampati scoring, mouth opening, and thyromental distance were used for airway assessment. The time needed for successful intubation (IT), number of attempts, number of failures, systolic (SBP), diastolic (DBP), mean blood pressure (MBP), heart rate (HR) and Oxygen saturation (O2) and damage to the lips, dentures, and pharyngeal or laryngeal structures were recorded. Continuous variables are presented as mean ± standard deviation and categorical variables are presented as frequency and percentage. Chi-square tests and Student\'s t-tests were used to compare the groups. P < 0.05 was considered statistically significant.
RESULTS: The groups were comparable regarding demographic data, preoperative airway parameters, IT, the number of attempts, O2, and the incidence of complications (P > 0.05). However, Bonfils intubation was associated with more stable HR, SBP, DBP and MBP (P < 0.05).
CONCLUSIONS: The Bonfils fiberoptic scope is comparable to a Macintosh laryngoscope but assures better hemodynamic stability. In difficult cases, the Bonfils scope is a better choice because of its ability to navigate.

OBJECTIVE: To test whether the mandibular retromolar region renders different results from the chin region with respect to the amount of bone available for the harvesting of block grafts.
METHODS: Sixty cone beam computed tomography (CBCT) scans of mandibles of adult patients without pathologic findings in the chin and retromolar region were included. According to the number of mandibular teeth, 20 CBCT data sets were allocated to each of the following groups: group M1: dentition 36-46; group M2: dentition 37-47; and group M3: dentition 38-48. For the potential donor sites in the chin and the retromolar regions, the volume (VChin , VRetro ), the length (LChin , LRetro ), the height (HChin , HRetro ) and the width (HChin , HRetro ) were assessed using a computer software. Moreover, the chin was examined for the presence and the localization of the mandibular incisive canal. To compare the donor sites in the chin and in the retromolar regions, the quotients VRetro /VChin , LRetro /LChin , HRetro /HChin and WRetro /WChin were calculated and tested using the Wilcoxon signed-rank test or the sign test.
RESULTS: The mean bone volume VChin measured 3.5 ± 1.3 cm(3) (SD), whereas the overall VRetro amounted to 1.8 ± 1.1 cm(3) (SD). VRetro amounted to 2.6 ± 1.4 cm(3) (SD) in the group M1, 1.8 ± 0.5 cm(3) in the group M2 and 1.0 ± 0.4 cm(3) in the group M3. For the group M1, VRetro /VChin measured 82 ± 39% (P = 0.036). VRetro /VChin reached 57 ± 20% in the group M2 and 32 ± 12% in the group M3 (P < 0.001). The mandibular incisive canal was detected in 97% of the CBCT scans. The distance between the mandibular incisive canal and the apices of the central incisors measured 10.5 ± 3.5 mm.
CONCLUSIONS: The amount of bone available for the harvesting of cortico-cancellous blocks in the chin region was superior in comparison with the mandibular retromolar region. In the absence of the second and the third molars, the amount of bone harvestable in the retromolar region reached approximately 80% of the bone volume available in the chin region. In the majority of the cases, the mandibular incisive canal was detected within the donor site in the chin region.

The retromolar foramen, retromolar canal, and retromolar nerve constitute a variation of the inferior alveolar nerve (IAN) with a prevalence of 12-75%; this represents type 1 bifidity of the IAN. The aim of this study was to assess the prevalence of the retromolar nerve in our population and to obtain related data. One hundred and thirty-six mandibles of fresh cadavers aged 20-75 years were dissected. The buccolingual location, diameter, and distance from the third molar, and their associations with sex, were measured. The area of innervation and demographic data were also documented and analysed statistically. The retromolar foramen and retromolar nerve were observed in 55 cases (40.4%). The mean diameter of the retromolar foramen was 1.7 mm (range 1.1-2.1 mm); the mean diameter was 1.8 mm in males and 1.5mm in females. Histological findings showed that the retromolar nerve extended from the anterior border of the ramus, innervating the retromolar pad and continuing to the buccal gingiva of up to two teeth anteriorly (first molar region). This high percentage of IAN type 1 bifidity (40.4%) suggests it to be a normal anatomical variation of the IAN rather than an anomaly.

Oncocytic neoplasms comprise a group of rare tumors of salivary glands. Histologically, World Health Organization (WHO) (1991) classified them into three distinct types: Oncocytosis, oncocytoma and oncocytic carcinoma. Oncocytoma is also known by the more descriptive and less confusing terms of oxyphilic adenoma and oxyphilic granular cell adenoma. Oncocytoma is a rare benign salivary gland neoplasm composed of large epithelial cells with characteristic bright eosinophilic granular cytoplasm (oncocytic cells). It accounts for approximately 0.4-1% of all salivary gland neoplasms, occurring primarily in parotid glands, with only a small percentage occurring in minor salivary glands of palate, tonsillar fossi, larynx, nasal cavity, maxillary sinus and the lacrimal gland. It occurs primarily in persons older than 50 years of age. According to some authors, the biologic behavior of oncocytomas arising from minor salivary glands is that of an aggressive nature and should be considered as low-grade malignancies. Only 17 cases of histologically verified oncocytoma of an intraoral minor salivary gland are reported in literature, the current case being the 18th. Owing to the lack of large series, assiduous study of the cases reported in the literature may lead to better understanding of this rare entity. We herein describe a rare and probably the first case of minor salivary gland oncocytoma involving retromolar area in a 32-year-old female patient with a brief review of literature.