Lower Molar Research Articles

Dielectric Response of Different Alcohols in Water-Rich Binary Mixtures from THz Ellipsometry.

We report a study on the hydrogen bonding mechanisms of three aliphatic alcohols (2-propanol, methanol, and ethanol) and one diol (ethylene glycol) in water solution using a time-domain ellipsometer in the THz region. The dielectric response of the pure liquids is nicely modeled by the generalized Debye-Lorentz equation. For binary mixtures, we analyze the data using a modified effective Debye model, which considers H-bond rupture and reformation dynamics and the motion of the alkyl chains and of the OH groups. We focus on the properties of the water-rich region, finding anomalous behavior in the absorption properties at very low solute molar concentrations. These results, first observed in the THz region, are in line with previous findings from different experiments and can be explained by taking into account the amphiphilic nature of the alcohol molecules.

Consumption of Feed Supplemented with Oat Beta-Glucan as a Chemopreventive Agent against Colon Cancerogenesis in Rats

Colorectal cancer (CRC) accounts for 30% of all cancer cases worldwide and is the second leading cause of cancer-related deaths. CRC develops over a long period of time, and in the early stages, pathological changes can be mitigated through nutritional interventions using bioactive plant compounds. Our study aims to determine the effect of highly purified oat beta-glucan on an animal CRC model. The study was performed on forty-five male Sprague–Dawley rats with azoxymethane-induced early-stage CRC, which consumed feed containing 1% or 3% low molar mass oat beta-glucan (OBG) for 8 weeks. In the large intestine, morphological changes, CRC signaling pathway genes (RT-PCR), and proteins (Western blot, immunohistochemistry) expression were analyzed. Whole blood hematology and blood redox status were also performed. Results indicated that the histologically confirmed CRC condition led to a downregulation of the WNT/β-catenin pathway, along with alterations in oncogenic and tumor suppressor gene expression. However, OBG significantly modulated these effects, with the 3% OBG showing a more pronounced impact. Furthermore, CRC rats exhibited elevated levels of oxidative stress and antioxidant enzyme activity in the blood, along with decreased white blood cell and lymphocyte counts. Consumption of OBG at any dose normalized these parameters. The minimal effect of OBG in the physiological intestine and the high activity in the pathological condition suggest that OBG is both safe and effective in early-stage CRC.

Comparing modified USPHS and FDI criteria for the assessment of glass ionomer restorations in primary molars utilising clinical and photographic evaluation.

To compare the applicability of modified US Public Health Service (USPHS) and FDI criteria for evaluating glass ionomer cement (GIC) restorations in primary posterior teeth through digital image analysis. This comparative analytic study was conducted at the Children's Dental Clinic RSKGM FKG UI, involving 40 GIC restorations on lower first primary molars in children aged 4-9years. After cleaning, the restorations were assessed clinically using modified USPHS and FDI criteria before taking digital images, then the collected images were re-evaluated using both sets of criteria, and the clinical assessment results were compared to the digital image assessment results. Statistical analysis revealed significant differences between the clinical evaluation of GIC restorations in primary teeth and their corresponding digital photographs when using the modified USPHS criteria, and although the use of FDI criteria yielded different results, these differences were not statistically significant. The assessment of GIC restorations through digital images aligns more closely with clinical assessments using the FDI criteria compared to the modified USPHS criteria.

Evaluating the Injection of Platelet-Rich Plasma on Second Lower Molars Protraction: A Randomized Controlled Clinical Trial.

Background The use of platelet-rich plasma (PRP) in dentistry was entered several decades ago, yet its clinical use in orthodontics still requires further investigation. The aim of this study was to evaluate the possible effects of local injection of PRP on the rate and typeof mandibular second molar protractionmovement compared with the comparator (no PRP) group. Material and methods Eighteen patients aged between 17 and 25 years were randomly allocated in a split-mouth study design to receive PRP injections on one sideimmediately before the start of molar protraction (PRP group), while the other side received only saline solution (comparator group). Eligibility criteria included bilaterally extracted mandibular first molars casesand indicated mandibular second molars protraction. The primary outcome of the study consisted of measuring the rate of molar protraction from the beginning of protraction (T0) to the end of the seventh month (TF), using a digital gauge. The secondary outcome included measuring the typeof second molar protraction movement between T0 and TFby lateral cephalometric images. Randomization of the intervention side was performed by picking out opaque sealed envelopes. The blinding of the principal investigator was impossible but blinding of the patient was achieved by injection of saline. Analyses were done using paired samples T-test to compare the changes in all variables between T0 and TF. The level of significance was taken at a P-value < 0.05. Results No significant difference was detected between the PRP and comparator groups in the rate of second lower molar protraction during seven months (0.56±0.07 mm per month in the comparator group, whereas, was 0.6±0.11 mm per month in the PRP group). Molar protraction parameters in both groups showed second lower molars moving by controlled tipping closer to bodily movement (Root Movement:Crown Movement≈0.8). Conclusions Platelet-rich plasma (PRP) is ineffective in accelerating the rate of orthodontic tooth movement (OTM) during molar protraction, and it has no effect on the type of tooth movement. In addition, the mechanics that we used (6 mm power arm in combination with miniscrews) are effective in mandibular second molar protraction by controlled tipping closer to bodily movement.

Wilson curve modification in permanent dentition: a retrospective comparison between clear aligners and continuous archwire treatment.

To evaluate leveling of the Curve of Wilson (COW) by two different treatment appliances (clear aligners [CA] and continuous archwire fixed appliances [FA]) in a permanent dentition sample of patients. Digital casts of 40 patients (CA group = 20 patients; FA group = 20 patients) were collected. Angular values for COW, right and left vertical height difference of lower first molars, and linear distance between lower teeth and the WALA ridge were analyzed for pre- (T1), posttreatment (T2) and on final virtual (ClinCheck) models (T2-CC) of the CA group. An unpaired t-test was used to evaluate significant intergroup differences (P < .05), while a paired t-test was used for posttreatment CA intragroup comparison. FA group showed better control of second molar crown positions compared to CA group (47-WALA = -0.2 ± 0.1 mm, 37-WALA = -0.6 ± 0.3 mm). No significant difference was detected for linear distance of lower first molars and the WALA ridge or for vertical height difference. CA group showed a greater reduction of distance between lower premolars and the WALA ridge (mean difference: -0.5 mm for both 45-WALA and 35-WALA; mean difference: -0.5 mm for 44-WALA, -0.6 mm for 34-WALA). Predictability for the CA group was high for every measurement (87% Right COW, 89% Left COW, 88% 46 Vertical Diff, 87% 36 Vertical Diff). Clear aligner and continuous archwire mechanics were effective in leveling COW. FA was more effective in changing crown position of lower second molars with respect to the WALA ridge, while CA provided a greater distance reduction between lower premolars and WALA ridges compared to FA.

Relationship between OSA pathophysiological phenotypes and treatment response to mandibular advancement devices: a pilot study.

We assessed whether critical pathophysiological phenotypes predict treatment response in patients with obstructive sleep apnea using a mandibular advancement device (MAD). Thirty-one patients with obstructive sleep apnea were treated with a MAD. Individuals were categorized and graded into 4 pathophysiological phenotypes based on polysomnographic features (anatomical, ventilatory control, arousal threshold, and muscle responsiveness). Morpho-anthropometric data were additionally assessed. Patients were classified as responders or nonresponders. Associations between polysomnographic phenotypes and treatment response were documented, as were morpho-anthropometric data and their impact on therapeutic success. There was a male predominance (64.5%), with a median age of 49 years (25th percentile: 40; 75th percentile: 55), body mass index = 27.4 kg/m2 (25th percentile: 26; 75th percentile: 28.8), and apnea-hypopnea index of 18.2 events/h (25th percentile: 11.7; 75th percentile: 27.6). The majority of patients treated with a MAD (58%) were good responders (68.0% mild and moderate vs 16.7% severe). Treatment response was associated with shorter intermolar and interpremolar distances in the lower arch (P = .0092 and .0129). Rapid eye movement sleep apnea-hypopnea index and MAD-related treatment response were inversely correlated (P = .0013). Favorable anatomical (P = .0339) and low muscle response (P = .0447) phenotypes were correlated with outcomes. According to our results, a favorable response occurred in a better "anatomical phenotype" and in the worse "muscular responsiveness phenotype" according to polysomnographic data. Furthermore, other favorable predictors, such as a rapid eye movement sleep apnea-hypopnea index < 16 events/h and a smaller distance between lower molars and premolars, were found. These findings indicate that clinical and polysomnographic aspects can discriminate phenotypes that may guide decisions on MAD treatment for obstructive sleep apnea. Manetta IP, Duarte BB, Nucci LB, Enes CC. Relationship between OSA pathophysiological phenotypes and treatment response to mandibular advancement devices: a pilot study. J Clin Sleep Med. 2024;20(8):1321-1330.

Origin of Melt Memory Effects in Poly(ethylene oxide): The Crucial Role of Entanglements.

The melt memory effect on crystallization is an intriguing phenomenon displayed by semicrystalline polymers, as opposed to low molar mass molecules. It concerns the effect of melt temperature on nucleation upon recrystallization. Typically, polymer crystals must be considerably superheated to erase the effect of previous morphology on the subsequent crystallization, avoiding an acceleration of the process. Despite being known for decades, its origin is still not fully understood. Investigating model poly(ethylene oxide) covering a wide range of molar mass, it is demonstrated that melt memory originates from topological constraints among the chains, i.e., entanglements, for PEO in which weak intermolecular interactions are present due to the ether groups. In fact, no memory is observed for samples below the critical molar mass for the formation of entanglements (about 1 kg mol-1). The increase in molar mass raises the number of entanglements and induces the formation of folded chains crystals, both factors leading to a topologically complex amorphous phase, enhancing the melt memory effect. The molecular origin of the melt memory effect in polymers with weak intermolecular interactions is thus ascribed to a slower isotropization in the melt of the chain segments originally contained in the crystals, due to the presence of entanglements among the chains. This study defines the distinction between small molecules and polymers from the point of view of melt memory.

Utilizing Intraoral Scanning and Computer-Aided Design/Manufacturing for Creating a New Dental Crown to Match an Existing Removable Prosthesis: A Case Report

This clinical report demonstrates the successful dental crown treatment for a 39-year-old female patient with a fractured posterior lower right second molar wearing a removable partial prosthesis and refusing to make a new one. The patient&amp;apos;s preference for a new dental crown on her lower right second molar was respected, and an intraoral scanner (IOS) was employed to capture the fractured abutment&amp;apos;s anatomy, which also serves as part of her removable denture. Following abutment preparation, a second IOS scan recorded the modified abutment. A temporary crown of the abutment was fabricated and secured to protect the prepared abutment. Comprehensive data, including an intraoral scan with an existing removable denture file, an intraoral scan without a removable denture, an intraoral scan of an unprepared abutment file, an intraoral scan of prepared abutment, and a digital photo of shade selection were transmitted to the dental laboratory. Utilizing computer-aided design/computer-aided manufacturing technology, a new dental crown compatible with the existing removable prosthesis was created. After fitting the new crown, occlusion, aesthetics, function, and attachment assessments were conducted to ensure optimal results. Subsequent follow-ups confirmed the patient&amp;apos;s satisfaction with the functionality, aesthetics, and fit of her removable partial denture with the new dental crown.

A new dryolestid fossil from the Late Jurassic illuminates molar root structure of dryolestids

ABSTRACT We report a micro-CT study of a new specimen of Dryolestes priscus (Dryolestidae, Cladotheria) from the Upper Jurassic Morrison Formation of Wyoming. The fossil (KUVP 134101) is an incomplete lower jaw preserving eight intact teeth, including two premolars (p3, p4) and six molars (m1–6), along with double-alveoli for m7 and a single alveolus for m8. Its preserved teeth and molar alveoli are consistent with the dental formula in more complete jaws of this species (i4.c1.p4.m8–m9). Here we have newly characterized diagnostic features on the molar trigonid of Dryolestes priscus and other species of Dryolestidae. Our analysis places this specimen close to Dryolestes priscus in terms of phylogeny. CT scans and visualization made it possible to illustrate the distinctive root structures of lower molars of dryolestid species. The two-rooted lower molars of D. priscus show a hypertrophied anterior root that is spatulate and much broader and longer than the simpler posterior root of the same molar. The disparate shape and size of the two molar roots are a highly derived pattern of dryolestids, which is absent in closely related genera formerly assigned to “paurodontids.” It is also unique among all mammaliaforms with typically two-rooted molars. The hypertrophied anterior root corresponds to most of the molar crown, and likely provided better support for occlusal forces acting on the large trigonid of the molar.

A Combination of Beta-tricalcium Phosphate, Plasmogel, and Platelet-rich Plasma Improves Long-term Bone Tissue Restoration after Complicated Lower Third Molar Surgery: A Nonrandomized Controlled Trial.

A surgical removal of the lower third molars can lead to a number of complications, and bone restoration typically takes a large amount of time. The aim of the study was to investigate the effect of the combination of beta-tricalcium phosphate (β-TCP), plasmogel, and platelet-rich plasma on postsurgery bone tissue restoration by means of X-ray. A total of 200 patients who underwent a complicated removal of the lower third molars were nonrandomly assigned to the experimental (EXP, n = 100) or control (CTR, n = 100) group. In the EXP group patients, sockets were filled with a combination of β-TCP, plasmogel, and platelet-rich plasma. In the CTR group, sockets were not treated. X-ray examinations were performed 3, 6, and 9 months (T1, T2, and T3) postsurgery to define bone quality on the Misch scale. The Mann-Whitney U-test was used for between-group comparison. Aside from the overconsumption of sugars (more frequently in CTR) and marginally significant sex ratio difference (more females in CTR), the groups were equivalent. Although both groups improved on bone density with time, the EXP group demonstrated greater restoration at T1 (U = 3431, P < 0.001), T2 (U = 3190, P < 0.001), and T3 (U = 3505, P < 0.001) related to a greater percentage of D2 (dense thick porous cortical bone on the ridge and a coarse underlying trabecular bone). A combination of β-TCP, plasmogel, and platelet-rich plasma, compared to no treatment, facilitates bone tissue restoration after complicated surgical removal of the lower third molars.

The Efficacy of an Extraoral Suction Apparatus on Reduction of Splatter Contamination during Impacted Lower Third Molar Surgical Procedure: An Observational Study.

The COVID-19 pandemic has affected the delivery of dental care globally. Air contamination during aerosol and splatter-generating procedures is of great concern to dental healthcare provider during these times. Extra oral suction (EOS) apparatus has been shown to be effective in preventing infection by control of aerosol. But very limited data is available regarding the efficacy of the apparatus in preventing splatter contamination. To assess the efficacy of EOS apparatus in reducing frequency and mean intensity of splatter contamination at clinician, assistant, patient sites during lower third molar surgical procedures. Patients who required surgical removal of an impacted lower third molar were divided into two groups (EOS and non-EOS) with 20 patients each. Universal indicating paper (UIP) was placed in specific locations on the surgeon, patient, and assistant. Colour changes after the settling of splatter on the UIP were analyzed to calculate the percentage intensity of splatter contamination. The use of an EOS device has shown an overall reduction in the total number of contaminated sites, with a difference of 6.36%. Surgeon, patient, and assistant sites showed reductions of 6.25, 10%, and 1.66%, respectively. The apparatus has showed statistically significant reduction of splatter frequency and intensity at the patient's chest and left shoulder regions respectively, during surgical removal of the impacted 48. The magnitude of splatter contamination during minor dentoalveolar surgical procedures is inevitable. Therefore, to achieve a better working environment, usage of an EOS apparatus is advocated.

Periodontal status and mandibular biomechanics in rats subjected to hyposalivation and periodontitis.

The aim this study was to compare the deleterious effects caused by experimental hyposalivation, periodontitis, and the combination of both on periodontal tissues and mandibular biomechanics in rats. Hyposalivation (group H) was induced through bilateral submandibulectomy. Periodontitis (group EP) was induced by injecting LPS (1 mg/ml) into the gingiva of the first lower molars. A third group was subjected to both conditions (group H+EP). Alveolar bone loss was evaluated by micro-computed tomography and histomorphometric analysis, and gingival inflammatory mediators were assessed by specific techniques. Biomechanical properties were evaluated in mandible. Alveolar bone loss increased similarly in groups H, EP and H+EP compared to control. Metalloproteinase (MMP2 and MMP9) activity was similar in H and control, but higher in groups EP and H+EP (MMP2: C 9644+2214, EP 34441+3336, H 5818+1532, H+EP 42673+3184; MMP9: C 5792+961, EP 14807+861, H 9295+520, H+EP 4838+1531). The rest of the inflammatory mediators evaluated increased in groups H, EP and H+EP to a greater or lesser extent with respect to the control, although in most cases, they were higher in groups EP and H+EP than in group H. The biomechanical properties of the mandible increased in group H compared to the other three groups. Both hyposalivation and periodontitis cause periodontal damage, but hyposalivation also produces biomechanical alterations, causing more extensive deleterious effects than periodontitis.

Dento-maxillary disharmony class I malocclusion with severe crowding, crooked canine, midline shifting and lip incompetence management: A case report

Objective: This case report aimed to provide treatment sequential DDM to meet the patient’s expectations. Case Report: Before starting the treatment, 2 first upper premolar needed to be extracted to gain space for severe anterior crowding teeth and 2 second lower molar because the teeth were not in good condition. After extraction, bracket placement with fixed appliance 0,22” MBT prescription and NiTi wires sequences were done for initial leveling. When it has already leveled, start for canine retraction using an elastomeric chain in wire SS 0,016x0,022-inch. Then, T-loop bends were used for anterior retraction in the same wire. Finishing detailing using SS 0,017x0,025-inch. The last one, Hawley Retainer, was used as a retainer. Results: The final results were as expected by the patient. She gained confidence through her new smile, and the orthodontist obtained what it needed for ideal occlusion except for Class I molar relationship because mesialization of the second lower mandibular tooth, and distalization of the anterior mandibular region but Class I canine were obtained, no rotation, no space, flat occlusal plane, and excellent crown angulation and inclination. Also, the patient’s lip became competent. Conclusion: This case concludes that the patient was happy with the overall treatment results and was satisfied with the pleasant and esthetic smile achieved at the end of the treatment.

Noninvasive conservative management of anterior open bite treated with TADs versus clear aligner therapy.

Anterior open bite can be treated non-surgically via molar intrusion using temporary skeletal devices (TAD). Clear aligner therapy (CAT) is recognized as a viable therapeutic modality for non-extraction treatment of adults with mild open bite. This study aimed to compare the treatment effect and mechanisms of open bite closure between patients treated with braces and TADs double arch intrusion and those treated with CAT. Treatment success at T3 was based on 1- positive overbite on ceph; 2- Change in the vertical dimension 3- post treatment POSI score equal to zero. The TAD group includes 18 consecutively treated patients from the main author. The CAT group consisted of 16 selected patients from three different orthodontists. The observation time points were as follows: pretreatment (T1), end of molar intrusion and positive overbite achieved (T2), end of treatment (T3), at least 6-month follow-up (T4). Treatment changes were assessed by cephalometric analysis and frontal intraoral photo. At the end of treatment, 100% of the patient of the TAD group and 78,6% of the CAT group had a posi score of 0. The TAD group showed a significant reduction in vertical measurements (SN-MPA: -1,55° ± 0.41, LAFH: -3,05 ± 0.51mm, U6-PP: -1.48 ± 0.30mm), but the CAT group did not have significant changes for these variables. Both groups had significant increases in overbite from T1 to T3 (TAD: 4,32 ± 0,5mm; CAT: 2,33 ± 0.56mm), and overbite remained stable at T4. The CAT group did not have a significant upper molar intrusion, but a significant extrusion of 1.22 ± 0.42mm of the lower incisor occurred. The TAD group achieved bite closure by upper molar intrusion, lower molar and incisors vertical control, and mandibular plane counterclockwise rotation, resulting in an improved AP and vertical relationship. The CAT group achieved bite closure through the lower incisor extrusion without significant change in the vertical dimension. This study provides relevant information about the skeletal and dental changes of open bite treatment with TADs double arch intrusion. The comparison with a control group treated with CAT confirms known information.

Displacement of lower third molar into parapharyngeal space. Case report

Displacement of lower third molar into parapharyngeal space. Case report

Evaluation of platelet rich fibrin on healing of impacted lower third molar extraction sockets

Evaluation of platelet rich fibrin on healing of impacted lower third molar extraction sockets

Prevalence of Impacted Third Molars Among Iraqi Patients Attending Al-Maghrib Specialized Dental Health Center in Relation to Age and Gender Using Panoramic Radiographs

Introduction: The most commonly impacted tooth is third molar. Aim: To investigate the prevalence of pattern of third molar impaction among patients attending Al-Maghrib specialized dental health center in Baghdad city. Materials and Methods: A cross-sectional analysis was conducted on digital orthopantomogram (OPGs) of high quality belonged to 519 patients referred to Al-Maghrib specialized dental health center in Baghdad city/Iraq between January2023 to June 2023. Data include age, gender and angulation type. Results: The age range was 20-70 years old. The prevalence of impacted third molar was 92%. The percentage of impacted lower third molar (51%) was higher than that of upper third molar (49%). Middle-aged patients (20-30, 31-40 years) recorded higher percentages of impaction than other age groups (31.7% and 32% respectively). Male gender revealed higher percentage (58%) of impaction than female gender (42%). Vertical and then mesioangular inclinations are the most prevalent types of lower third molar angulations (45% and 30% respectively). Conclusion: Higher prevalence of impaction in third molars was recorded in the current study that was more prevalent in the middle-aged patients with male predilection. The impaction was more common in the mandible than the maxilla. The most prevalent lower third molar angulation is vertical followed by mesioangular.

Compressive stress in three types of finishing lines with lithium disilicate crowns in permanent teeth: finite element analysis

In oral rehabilitation, the use of ceramic restorations is widely accepted due to its aesthetic capacity to mimic the naturalness of the dental tissue, provide longevity of the material, and present a greater marginal fit compared to crowns with a metal structure. Termination lines are biological preparations whose function is to minimize the cervical opening of the marginal seal. Consequently, analyzing the behavior of restorative materials under compressive forces decreases the risk of fracture and increases the success of the treatment. To compare the compressive stresses of lithium disilicate crowns with three different finishing lines. In silico study of the simulation of a dental preparation on a lower right first molar with chamfer (0.6 mm), shoulder (0.5 mm) and deep chamfer (0.5 mm) finish lines. Using the SolidWorks®️ version 2017 software, the maximum stresses, minimum stresses, and location of the compressive force were collected on the Megapascal (Mpa) measurement scale. The chamfer type termination line (0.6mm) obtained a lower compressive stress compared to the other two shoulder type termination lines (0.5mm) and deep chamfer (0.5mm). It was shown that the chamfer type finishing line (0.6mm) presented a better force distribution, determining greater reliability in the selection of this finishing line with the use of a lithium disilicate crown in a unitary manner.

Evaluation of the skeletal and dental effects of a hybrid aesthetic functional appliance (HAF) in skeletal class II division 1 malocclusion: A prospective uncontrolled clinical trial.

The present study investigated the skeletal and dental effect in class II division I growing patients due to mandibular deficiency treated with the hybrid aesthetic functional (HAF) appliance. A sample of 16 growing patients (5 boys and 11 girls; mean age: 9.50 years, standard deviation: 1.15) with class II division I malocclusion were treated using the HAF appliance for an average period of 10±3 months. For each patient, a cephalometric radiograph was taken before and after treatment, and digital analysis was applied using the WebCeph program. The statistical analysis was performed to evaluate dental and skeletal changes associated with the HAF appliance and determine if there were any statistically significant variations in anatomical measurements between the start and completion of the treatment. The data showed a significant increase in SNB angle (P=0.002), leading to a significant decrease in ANB angle (P=0.001). The mandibular length significantly increased (P=0.008), the lower incisors were flared significantly (P=0.028), and the lower molars were extruded significantly (P≤0.001). Also, this study revealed a significant decrease in Wits appraisal (P≤0.001), overjet (P≤0.001), and overbite (P=0.041). Additionally, a significant increase in lower anterior facial height (P≤0.001), total facial height (P=0.001), and posterior facial height (P=0.037) were observed. The HAF appliance showed that it could be used to correct class II division 1 skeletal discrepancy by mandibular advancement. The HAF appliance increased all facial heights significantly.

Dental age assessment and dental scoring systems: combined different statistical methods.

Age Estimation has been considered as a human basic right, carried out through the use of tables for dental age assessment based on the chronology of tooth eruption. As such, the final aim of this investigation is to create tables with applicability to the Portuguese population, for the different scoring systems used and combined different statistical approaches. For this purpose, dental age assessment was achieved in all four third molars, using different scoring systems, in a total sample of 626 orthopantomograms (324 females, 302 males), aged between 12 and 25 years old, from the database population of Lisbon North University Hospital Center, approved by the Ethic Committee. The values of validation showed excellent results both on precision and on reproducibility. Mostly all methods showed statistically significant differences between the estimated age and the chronological age and, therefore, the presence of estimation errors. Kullman's and Mincer's methods are the ones with best applicability in the Portuguese population, in the lower third molars. The reliability measures (sensitivity, specificity and accuracy) values decrease as age increases. A combination of the scoring systems as a protocol for dental age assessment in Portuguese nationality was established. Tables, for all the scoring systems used, were made with applicability in the Portuguese population.