Left Molar Research Articles

Flipped autograft: A novel approach for management of wound dehiscence in implant dentistry. A case report

Introduction and importanceThis case report describes a novel technique for management of peri-implant wound dehiscence that involves using auto graft from the same surgical site to seal the dehiscence defect.Case presentationA 21-year-old female was referred for extraction of a non-restorable lower left first molar and replacement by immediate dental implant. Following attachment of the cover screw bone graft biomaterial and collagen membrane was secured over the biomaterial and buccal flap was coronally positioned and sutured. Patient was seen 1 week after surgery for follow up where a minor wound dehiscence was discovered with some biomaterial particles exposed. Patient was advised to continue strict oral hygiene control and to wait for another week. After 2 weeks of the implant placement surgery patient came back for dehiscence management visit where an innovative flipped autograft technique was performed to seal the dehiscence defect.Clinical discussionHealing by primary intention was achieved that led to uneventful healing and hence a successful well-functioning restoration with clinically healthy soft tissue and optimal aesthetic outcome.ConclusionsPeri-implant wound dehiscence can be successfully treated by the novel flipped autograft technique that yielded great aesthetic and functional results.

Unloading of occlusal force aggravates alveolar bone loss in periodontitis.

Periodontitis (PD), a chronic infectious inflammatory disease initiated by bacteria, is associated with several local contributing factors including occlusal trauma. Previous studies have found that the traumatic occlusal force could aggravate alveolar bone loss during PD. However, the effect of reduced occlusal force during PD remains unclear. This study aimed to explore the effect of occlusal force unloading on PD onset and progression and its underlying mechanism as an effort to provide restoration suggestions for PD patients with dentition defect in clinic. This study might also propose occlusal force unloading could be a new local contributing factor for PD. C57BL/6 mice were used to establish a PD model by the ligation of 5-0 silk around the mandibular left first molar (PD group) and an unloading experiment model by the extraction of their left maxillary first molar (EX group). The THP-1-derived macrophages were used to verify in vivo results. Micro-CT scanning and H&E staining results consistently showed that PD + EX group experienced the most severe alveolar bone resorption as compared to PD group and control group. Further RNA-sequencing analysis suggested that occlusal force unloading significantly enhanced osteoclastic resorption, inhibited osteoblastic activity, and promotes M1 and M2 macrophages polarization. Immunofluorescence staining (IF) results showed that compared with the PD group, PD + EX group significantly increased the ratio of M1/M2 polarization. Similar results were observed by RT-qPCR and IF in vitro: removal of compressive force led to an increased ratio of M1/M2 polarization in LPS-stimulated THP-1-derived macrophages. Our study demonstrated that occlusal force unloading aggravates bone resorption by increasing the ratio of M1/M2 macrophages polarization during PD, suggesting a previously unknown local contributing factor for PD, and providinga novel insight for dentists to restore missing teeth as an effort to maintain remaining dentition.

MULTIPLE DENTIGEROUS CYSTS IN A PEDIATRIC PATIENT: CASE REPORT

Although dentigerous cysts are the most common developmental odontogenic cysts, multiple synchronous lesions in nonsyndromic patients are a rare event. A 10-year-old patient was admitted to the intensive care unit presenting painful progressive bilateral facial swelling. Medical history was unremarkable. Intraoral examination revealed an increase of volume in the region of the bilateral mandibular and left maxillary molars. Magnetic resonance imaging showed expansive and well-defined lesions in those regions, associated with the crown of the impacted second molars. Under general anesthesia, aspiration was performed, and a yellowish fluid content was observed. Enucleation of the cystic lesions was performed along with extraction of the involved second molars. Histopathologic analysis revealed fragments of cystic lesions lined by a thin, nonkeratinized odontogenic epithelium, leading to the diagnosis of multiple dentigerous cysts. The postoperative period was uneventful and the patient does not show clinical or radiographic signs of recurrence after 2 years of follow-up. Although dentigerous cysts are the most common developmental odontogenic cysts, multiple synchronous lesions in nonsyndromic patients are a rare event. A 10-year-old patient was admitted to the intensive care unit presenting painful progressive bilateral facial swelling. Medical history was unremarkable. Intraoral examination revealed an increase of volume in the region of the bilateral mandibular and left maxillary molars. Magnetic resonance imaging showed expansive and well-defined lesions in those regions, associated with the crown of the impacted second molars. Under general anesthesia, aspiration was performed, and a yellowish fluid content was observed. Enucleation of the cystic lesions was performed along with extraction of the involved second molars. Histopathologic analysis revealed fragments of cystic lesions lined by a thin, nonkeratinized odontogenic epithelium, leading to the diagnosis of multiple dentigerous cysts. The postoperative period was uneventful and the patient does not show clinical or radiographic signs of recurrence after 2 years of follow-up.

THE BUCCAL BIFURCATION CYST: A CASE REPORT

We present a case of a 6-year-old male patient whose parents reported a painful, slow-growing intraoral mandibular swelling, which was considerably reduced by the time of examination. Clinical inspection revealed a relation to the left permanent lower first molar at normal eruption process and a positive response to sensibility test. A panoramic radiography showed a well-defined homogeneous radiolucent area involving the molar roots on bifurcation zone. A cone beam computed tomography was requested, which was able to confirm the buccal location. The exam also revealed 10 mm of extension and a suggestive image of proliferative periostitis on the overlying cortical bone. The first diagnostic hypothesis was buccal bifurcation cyst, and the chosen treatment was surgical enucleation. The material was sent for histopathologic analysis, which confirmed the diagnosis. Currently, the patient is after 5 months of the procedure, the patient is with good evolution.

A MODIFY SAGITTAL SPLIT OSTEOTOMY FOR ODONTOGENIC KERATOCYST SURGICAL TREATMENT

A 21-year-old male patient, on medication for schizophrenia, was forwarded from another service after an incisional biopsy that resulted in diagnosis of an odontogenic cyst. The first physical exam presented facial symmetry, satisfactory mouth opening, pain during palpation on the left lingual floor, and intraoral swelling. Orthopantogram and computed tomography revealed an osteolytic intraosseous well-defined lesion measuring about 45 × 16 × 12 mm and bone expansion located on the mandibular left side, surrounding the crown of an unerupted third molar. Due to the noncollaborative behavior, an excisional biopsy was programmed. The surgery was performed by a mandibular intraoral approach, modified sagittal split osteotomy, enucleation of the lesion, peripheral ostectomy in the surgical site, and buccal bone cortex fragment before lower left third molar extraction. The buccal cortical fragment was fixed in the original position by 2 titanium plates and 10 screws. After 32 months of follow-up there are no signs of recurrence.

Anatomical variations and bilateral symmetry of roots and root canal systems of mandibular first permanent molars in a Saudi Arabian population utilizing cone beam computed tomography

<h3>Objective</h3> To evaluate the anatomical variations of the roots and root canal systems and to determine the symmetry between right and left mandibular first permanent molars in a Saudi Arabian population using images derived from cone beam computed tomography (CBCT) scans. <h3>Methods</h3> CBCT scans (with exposure parameters 90 kVp, 5–8 mA, 17.5 s exposure time, and 0.25 mm voxel size with a 170 × 120 mm FOV) were retrieved from the database and axial, coronal, and sagittal sections of the mandibular first molars were examined. The number of roots, number of canals, and type of canal configuration based on Vertucci's classification were recorded. Bilateral symmetry between right and left sides of the same individuals and differences between genders were investigated. <h3>Results</h3> Out of 174 mandibular first molars, 97.1% were two rooted and 2.9% were three rooted (with a distolingual root). In regards to the number of canals, 73% had three, 25.3% had four and 1.7% had two root canals. In teeth with four root canals, 90.9% of the extra canals were in the distal root, while 9.1% were in the extra distolingual root. The most common canal configurations in the mesial and distal roots were type IV (64.9%) and type I (77%), respectively. Symmetrical analysis revealed 100% symmetry in number of roots and 56.4% in number of canals between right and left teeth in the same individual. <h3>Conclusion</h3> An extra root was seen in few cases of mandibular first molars of the studied population. A wide range of canal configurations was noted, with high prevalence of type IV in the mesial root and type I in the distal root. No associations between gender and root anatomy and canal morphology were discovered. Although high bilateral symmetry was found in numbers of roots, it varied with regards to numbers of canals and canal configurations in the same individuals. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel

SEVERE MUCOSITIS AND ORAL COMPLICATIONS IN A LEUKEMIC PEDIATRIC PATIENT

The aim of this study is to report a case of a pediatric patient with severe oral mucositis, toothache, and gingivitis as a consequence of chemotherapy (CTX) treatment. An 11-year-old female patient diagnosed with acute lymphocytic leukemia was referred to the dentistry service because of suspension of CTX due to oral lesions. The patient reported oral pain and toothache and was not performing oral hygiene tasks. On intraoral examination, there were erythematous, atrophic, desquamative, and ulcerated lesions with pseudomembrane on the tongue and buccal and labial mucosa. There was also gingival bleeding, decayed teeth, and pulp exposure in the upper left first molar. Oral hygiene instructions, prescription of salivary substitute, topical antifungal, and low-level laser therapy were performed. The complete adequacy of oral cavity was assessed. The introduction of dentistry in the multidisciplinary treatment of patients with cancer is extremely important for the prevention, control, and treatment of oral complications from CTX.

MULTIDISCIPLINARY TREATMENT AND FOLLOW-UP OF AMELOBLASTOMA: CASE REPORT

Ameloblastoma is a benign epithelial odontogenic neoplasm with aggressive biological behavior and a tendency for local recurrence. A 21-year-old male patient was referred for treatment for an asymptomatic small intraoral swelling on the left posterior mandible. Clinical examination showed the absence of left molars and no extraoral asymmetry. Panoramic radiography revealed a unicystic radiolucent lesion. Previously, the patient was submitted to an incisional biopsy with a histopathologic diagnosis of ameloblastoma. The treatment was excision of the lesion followed by peripheral osteotomy and application of Carnoy's solution, and the surgical specimen was sent for histopathologic analysis. Microscopic examination confirmed the diagnosis of ameloblastoma presenting proliferation of islands and cords of odontogenic epithelium. Peripheral cells were arranged in a palisading pattern with reverse polarity and central cells were loosely arranged. The stroma consisted of fibrous connective tissue. The patient has been under follow-up for about 2 years without recurrence.

JUVENILE PSAMMOMATOID OSSIFYING FIBROMA: A CASE REPORT

Ossifying fibroma represent neoplastic entities and are separated into trabecular and psammomatoid variants. A 10-year-old girl sought dental care, complaining of facial volume increase that had been present for a year. On extraoral exam, an increase in volume on the left side of the lower third of the face, causing facial asymmetry, was observed. On intraoral examination, there was swelling near the first lower left molar with similar coloring to the mucosa. On radiographic examination, a unilocular radiolucent lesion with scalloped edges, involving the mandibular body and causing root resorption of the first lower molar, was noted. An incisional biopsy was performed and a final diagnosis of juvenile psammomatoid ossifying fibroma was made. Finally, bloc resection of the lesion and reconstruction with a titanium plate were carried out. After 3 months, the patient remains without signs of recurrence. Ossifying fibroma represent neoplastic entities and are separated into trabecular and psammomatoid variants. A 10-year-old girl sought dental care, complaining of facial volume increase that had been present for a year. On extraoral exam, an increase in volume on the left side of the lower third of the face, causing facial asymmetry, was observed. On intraoral examination, there was swelling near the first lower left molar with similar coloring to the mucosa. On radiographic examination, a unilocular radiolucent lesion with scalloped edges, involving the mandibular body and causing root resorption of the first lower molar, was noted. An incisional biopsy was performed and a final diagnosis of juvenile psammomatoid ossifying fibroma was made. Finally, bloc resection of the lesion and reconstruction with a titanium plate were carried out. After 3 months, the patient remains without signs of recurrence.

CLINICAL, RADIOGRAPHIC AND MORPHOLOGICAL FEATURES OF AMELOBLASTOMA: A CASE REPORT

Ameloblastoma is a benign epithelial odontogenic neoplasm with an aggressive biological behavior with a tendency of local recurrence. A 21-year-old male patient was referred for treatment for an asymptomatic small intraoral swelling on the left posterior mandible. Clinical examination showed the absence of left molars and no extraoral asymmetry. Panoramic radiography revealed an unicystic radiolucent lesion. Previously, the patient was submitted to an incisional biopsy with a histopathologic diagnosis of ameloblastoma. The treatment was excision of the lesion followed by peripheral osteotomy and application of Carnoy's solution, and the surgical specimen was sent for histopathologic analysis. Microscopic examination confirmed the diagnosis of ameloblastoma presenting proliferation of islands and cords of odontogenic epithelium. Peripheral cells were arranged in a palisading pattern with reverse polarity and central cells were loosely arranged. The stroma consisted of fibrous connective tissue. The patient has been under a follow-up for about 2 years without recurrence.

Impacts of Glucose-Dependent Insulinotropic Polypeptide on Orthodontic Tooth Movement-Induced Bone Remodeling.

Glucose-dependent insulinotropic polypeptide (GIP) exerts extra-pancreatic effects via the GIP receptor (GIPR). Herein, we investigated the effects of GIP on force-induced bone remodeling by orthodontic tooth movement using a closed-coil spring in GIPR-lacking mice (GIPRKO) and wild-type mice (WT). Orthodontic tooth movements were performed by attaching a 10-gf nickel titanium closed-coil spring between the maxillary incisors and the left first molar. Two weeks after orthodontic tooth movement, the distance of tooth movement by coil load was significantly increased in GIPRKO by 2.0-fold compared with that in the WT. The alveolar bone in the inter-root septum from the root bifurcation to the apex of M1 decreased in both the GIPRKO and WT following orthodontic tooth movement, which was significantly lower in the GIPRKO than in the WT. The GIPRKO exhibited a significantly decreased number of trabeculae and increased trabecular separation by orthodontic tooth movement compared with the corresponding changes in the WT. Histological analyses revealed a decreased number of steady-state osteoblasts in the GIPRKO. The orthodontic tooth movement induced bone remodeling, which was demonstrated by an increase in osteoblasts and osteoclasts around the forced tooth in the WT. The GIPRKO exhibited no increase in the number of osteoblasts; however, the number of osteoclasts on the coil-loaded side was significantly increased in the GIPRKO compared with in the WT. In conclusion, our results demonstrate the impacts of GIP on the dynamics of bone remodeling. We revealed that GIP exhibits the formation of osteoblasts and the suppression of osteoclasts in force-induced bone remodeling.

Effect of maxillary molar intrusion on surrounding bone density during treatment of anterior open bite

The aim of the current work is to estimate the impact of posterior maxillary intrusion on the surrounding bone intensity during correction of anterior open bite (AOB). The sample was 14 patients suffering from mild to moderate (3-5mm) anterior open bite with increased posterior maxillary vertical height. This study sample was allocated into two groups according to the corticotomy the approach. Buccal miniplates and palatal mini screws were used as skeletal anchorage for maxillary molars’ intrusion. The density of the alveolar bone related to right and left maxillary first permanent molars were measured 4.5 months after intrusion commencement. The study revealed that the alveolar bone density of right and left first permanent molars had statistically significant decreases. In the right side, buccal and palatal cortical density had statistically significant decrease, however it was non significant for left both cortical bone. Absolute molar intrusion could be attained by skeletal anchorage miniplates and mini screws in patients with frontal open bite malocclusion. The variation of bone intensity between buccal and palatal sides may account for the variance bone thickness changes after intrusion from the buccal to the palatal sides.

Study of Lateral Wall Thickness of the Maxillary Sinus in Left and Right Sides for Female and Male: A Cross Sectional Retrospective Study Using Cone Beam Computed Tomography.

Dental implants are considered the first option to replace missing teeth. Alveolar bone resorption gradually progresses following tooth extraction leading to loss of vertical bone dimension for implant placement. The lateral window approach is the most commonly used procedure to treat vertical bone loss. The aim of the present study is to evaluate the Lateral Wall Thickness (LWT) of the maxillary sinus and determine the influence of gender and side on maxillary LWT. This study involved a cross sectional retrospective study. Cone- beam computed tomography data were collected from 99 patients with a total of 198 maxillary sinuses that met the inclusion criteria. The patient age ranged between 18 to 35 years. On the selected sagittal section, the points of measurement are determined by a perpendicular line at 5 mm from the lowest point of the sinus floor. Measurements were taken at four different areas; first premolar (P1), second premolar (P2), first molar (M1), and second molar (M2). Descriptive statistics were used to calculate mean lateral wall thickness for each tooth, and student's t-test was used to test the effect of gender and side on maxillary LWT. The greatest mean LWT was observed around the left first maxillary molar (2.43±0.82), while the lowest mean LWT was observed around the right second maxillary premolar (1.62±0.61). There was no significant difference in the LWT around any tooth (M1 p=0.56, M2 p=0.92, P1 p=0.14, P2 p=0.19). There was no significant difference in both males and females of the lateral wall thickness in the left and right side of maxillary sinus.

A Modified Hyrax-Type Expander Is Effective for Distal Bodily Movement of the Maxillary First Molar

Impaction and eruption disturbance of permanent teeth are frequently encountered in orthodontic practice. The canine teeth play an important role both functionally and esthetically. Eruption disturbance of a maxillary canine, if left untreated, can cause not only disturbed jaw movement and esthetic problems, but also root resorption of adjacent permanent teeth, and thus should be diagnosed and treated appropriately. In this report, we present a case of a patient with eruption disturbance of the maxillary left canine in which the maxillary left second molar was extracted and the maxillary left first molar was distally moved with a Hyrax-type expander (Veltri Monolateral Screw®; Leone, Firenze, Italy) designed to enable the distal movement of a unilateral first molar in order to create eruption space for the maxillary left canine, resulting in smooth distal molar movement and alignment of the left maxillary canine in the dental arch. Furthermore, the maxillary third molar was also aligned to achieve a good occlusal relationship without reducing the number of teeth.

Effect of masseter muscle mass on the rate of experimental tooth movement in rats.

Previous clinical observational studies have suggested that orthodontic tooth movement (OTM) is related, at least partly, to the mass and/or capabilities of the masticatory muscles. Our study aimed to examine the influence of masticatory muscle mass on the OTM in an animal experimental model in which the masseter muscle was modulated by botulinum neurotoxin type A (BTX) injection. Eighteen Wistar rats were equally divided into two groups: BTX injection and control. BTX was injected bilaterally into the masseter muscles. Three days after the injection, the maxillary left first molars were orthodontically moved for 14 days. At the end of the experiment, micro-computed tomography was performed to evaluate the rate of OTM and bone morphometry. The masseter muscles were weighed and prepared for histological analyses. The masseter muscle mass in the BTX group was less than that in the control group, and histological findings showed atrophy of muscle fibres. The rate of OTM was significantly higher in the BTX group than in the control group. Furthermore, a negative correlation was detected between masseter muscle mass and OTM in the BTX group. Bone morphometry showed no difference between the control and BTX groups. Decreased masseter muscle mass was found to be closely related to an increase in the rate of OTM in rats using BTX injection to modify the masseter muscle mass. Masseter muscle mass could be a predictive factor for OTM in rats injected with BTX.

THIRD MOLAR MATURITY INDEX IN INDONESIAN JUVENILES: COMPARING LINEAR AND POLYNOMIAL KERNEL PERFORMANCE IN SUPPORT VECTOR REGRESSION FOR DENTAL AGE ESTIMATION

Dental age estimation is a branch of forensic odontology that plays a pivotal role in identifying, examining, or determining the legal status of the living and the dead. This research explores the capability of support vector regression to estimate chronological age from the third molar maturity index (I3M) in Indonesian Juveniles and compares the linear and kernel performance. Two hundred and twenty-two orthopantomo-graphy were measured using I3M in the lower left third molar and processed using R Studio with Caret extension. The analysis was separated into two groups, group 1 using only I3M as a predictor, and group 2 using both I3M and sex. Both groups were analyzed using SVR with the linear and polynomial kernel. The result suggests that using polynomial kernel SVR in group 1 produces the best results, with an R2 value of 0.64, RMSE of 1.588 years, and MAE of 1.25 years using degree = 3, c = 0.25. However, the addition of a sex predictor in the model reduces its accuracy when using the polynomial kernel.

THE EFFECTIVENESS OF ANCHOVY INTAKE ON EPITHELIAL SOCKET THICKNESS POST EXTRACTION

Background: Epithelial formation or re-epithelialization is one of the parameters in the wound closure. Nutrition has become a major factors in the successful outcome during this process. Anchovy (Stolephorus sp.) contains several proteins, vitamins, and minerals that can act as supplements to support wound closure. This research proposed to understand the effect of anchovy intake toward epithelial thickness of the rats post tooth extraction. Method: This research was an experimental laboratory with a post-test-only control group design using 24 rats as a sample. Rats were divided into 2 groups, the control and the treatment group with 12 rats each. The mandibular left first molar of the samples was extracted, then given with aquadest (the control) and anchovy powder (the treatment) during 3, 5, and 7 days. All rats were decapitated after 24 hours from the last treatment, followed by tissue processing and staining with Hematoxylin-Eosin (HE) for examination. A microscope that connects with optilab on a magnification of 100x was used to measure the epithelial thickness on the thickest and thinnest part of the epithelial. The data were analysed with One-way ANOVA test and LSD test. Result: The results showed that the epithelial thickness of the treatment group was significantly increased compared to the control group (p&lt;0.05). Conclusion: This study concludes that the anchovy (Stolephorus sp.) intake affects increasing epithelial socket thickness of the rats post tooth extraction.

Mechanical analysis of three-unit metal-free fixed dental prostheses produced in different materials with CAD/CAM technology.

The aim of this study was to evaluate the mechanical analysis of different three-unit metal-free fixed dental prostheses (FDPs) produced by computer-aided design (CAD)/computer-aided manufacturing (CAM). A hundred stainless steel die models of a mandibular left first premolar and a mandibular left first molar were prepared. The specimens were divided into five CAD/CAM material groups (n = 20): Group ZIR, a cubic zirconia (DD cube ONE®); Group FRC, FRC resin material (Trinia); Group PEEK, a PEEK material (KERA® starPEEK); Group PEKK, a PEKK material (Pekkton® ivory); and Group COMP, a polymer composite material (BreCAM.HIPC). Compression test was applied to the specimens, and then the results were analyzed statistically using one-way ANOVA and Tukey's tests. In addition, deformation analyses in FDPs were compared with finite element method (FEM). After the compression test, the damage to FDPs was evaluated with a scanning electron microscopy. Although ZIR (2461 ± 93.70N) showed high fracture load values, FRC (1571 ± 35.96N) material was found to be advantageous in terms of toughness. These were followed by PEEK (1398 ± 38.26N), PEKK (1227 ± 44.25N), and COMP (829 ± 32.33N), respectively. A ductile fracture was observed in PEEK, PEKK, and FRC due to their elastic structures. The deformation properties examined by the FEM were found to be similar to the compression test. CAD/CAM high-performance polymers and cubic zirconia material can be used in three-unit FDPs. In three-unit FDPs, the use of FRC material can be advantageous due to both biomechanics and lightness. Metal-free CAD/CAM materials may offer new possibilities in three-unit FDPs.

Odontogenic Brain Abscess Caused by &lt;i&gt;Fusobacterium nucleatum&lt;/i&gt; in an Elderly Man Presenting with Convulsions

We report a case of odontogenic brain abscess caused by Fusobacterium nucleatum. An 82-year-old man presented to us with a history of convulsions. He did not have a history of fever or headache. Brain magnetic resonance imaging findings suggested a brain abscess in the left frontal lobe, and the patient was initiated on treatment with anticonvulsants and antibiotics. While the lesion was monitored to assess the effect of the antibiotics, it was found to enlarge rapidly. Therefore, we performed trephine drainage, and F. nucleatum was identified on culture of the abscess fluid. Intraoral examination revealed periodontitis in the left mandibular molars. Postoperatively, his convulsions stopped with antiepileptic treatment. The patient was diagnosed as having an odontogenic abscess, and treated with antibacterial agents and oral care. This was a case of an odontogenic abscess caused by F. nucleatum in an elderly male patient. A good outcome was obtained by performing an early surgical procedure with administration of the appropriate antibacterial agent. Although it has been suggested that brain abscesses caused by Fusobacterium species may be complicated systemic and invasive infection, appropriate treatment should be administered, including timely surgical intervention and use of the appropriate antibacterial agents, because of the high sensitivity of the infection to antibiotics.

Root canal width as a mandibular maturity marker at the 18-year threshold in the Maltese population.

The determination of age of majority (the 18-year-old threshold) using the popular Demirjian tooth staging method is unreliable, so other maturity markers are required. This study examines whether the ratio of the root canal widths (RCW) of the mandibular first, second and third molars is a useful indicator of age. Nine hundred eighteen dental panoramic radiographs (DPT) were examined and the ratio of the mid-points of the distal roots of the left mandibular first, second and third molars assessed according to the RCW stages as described by Roberts (J Forensic Sci 62:351-354, 2017). Individuals who had reached stages RCW-A and RCW-B were represented in a wide range of ages spanning the 18-year-old threshold. Individuals who had reached Stage RCW-C were all above the 18-year-old threshold. It was not possible to analyse a large number of DPTs for various reasons. Individuals categorised as stage RCW-C may be deemed to have reached the 18-year-old threshold. These results are consistent with other published studies. Variation in root morphology and in the rate of development of the third molar limits the applicability of this method. RCW staging is an accurate method of determining the 18-year-old threshold. Its limited applicability requires the use of substitute markers in a large number of cases.