Evaluation of the maxillary third molar position and its relationship with the maxillary sinus: a CBCT study

Objectives

The present study investigated the position and relationship of the maxillary third molars to the maxillary sinus. These molars were detected to have a close relationship with the maxillary sinus based on panoramic images, using cone-beam computed tomography (CBCT).

Methods

This retrospective study evaluated 162 impacted third molars from 100 patients that showed a superimposed relationship between the maxillary sinus and third molars on panoramic images obtained from CBCT. CBCT images were used to assess the horizontal (buccopalatal) and vertical positions of the maxillary sinus relative to the maxillary third molars, proximity of the roots to the sinus, and angulation and depth of the third molars. The associations among the angulation, depth of third molars, and horizontal and vertical positions of the maxillary sinus relative to the third molar findings were examined using Chi square tests.

Results

Based on the winter classification, the most frequent tooth position was vertical (59.9 %), followed by mesioangular (14.2 %), distoangular (9.9 %), and others. Most impacted teeth were at the level between the occlusal and cervical levels of the adjacent second molar. Regarding the relationships of the maxillary third molars with the maxillary sinus examined on CBCT, vertical type III (buccal root related with maxillary sinus) (34 %) and horizontal type 2 (maxillary sinus located between roots) (64.8 %) were seen most frequently.

Conclusions

The relationship between the maxillary sinus and third molar roots should be considered during extraction. When a risk of sinus perforation is predicted in an extraction, a presurgical CBCT examination could be valuable.

     

A retrospective study of the prevalence and characteristics of root dilaceration in a sample of the Turkish population

Objectives

We aimed to determine the prevalence and distribution of root dilaceration by tooth type and to investigate the relationship between trauma history and teeth with dilaceration in a large population of adult dental patients in Turkey.

Methods

Periapical radiographs of 9,406 permanent teeth from 5,504 patients were examined. Teeth were recognized as having mesial or distal root dilaceration if there was deviation of 90° or more from the normal long axis of the tooth. The patients’ biographic data, dilacerated and non-dilacerated teeth, and accidental trauma history were recorded. The Pearson Chi-square test was used to evaluate differences by sex and the Mann–Whitney U test was used to determine whether significant differences existed in the occurrence of dilaceration by age and side.

Results

In the 5,504 subjects (2,877 males and 2,627 females), 9,406 teeth (5,029 in males and 4,377 in females) were examined. The Mann–Whitney U test revealed no significant differences in root dilacerations by age (P = 0.6) The teeth most frequently observed with root dilaceration were mandibular third molars (10.7 %), followed by maxillary first molars (5.8 %), mandibular second molars (5.2 %), maxillary third molars (5.0 %), maxillary second molars (4.9 %), and mandibular third molars (4.9 %). Overall, there were 161 right and 156 left root dilacerations. In all patients, the root dilacerations were unilateral. Trauma occurred in 1 % (n = 59) of the population, and all cases were in the maxillary arch. Trauma involved 0.6 % of all teeth examined, and was most common in maxillary third molars (2.6 %), followed by maxillary first molars (1.9 %), maxillary second molars (1.3 %), and maxillary lateral incisors (1.3 %) (P > 0.05). In 252 of 317 dilacerated teeth (79 %), the dilaceration was observed in the apical third region.

Conclusions

Clinicians should consider the possibility of root dilaceration in teeth with trauma history. When other treatment (such as extraction, orthodontics) is required, identification of a dilaceration is important to ensure appropriate management. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations.     

Symmetry of Root and Root Canal Morphology of Maxillary and Mandibular Molars in a White Population: A Cone-beam Computed Tomography Study In Vivo

Introduction

The aim of the present study was to use cone-beam computed tomography (CBCT) to analyze root canal anatomy and symmetry of maxillary and mandibular first and second molar teeth of a white population.

Methods

A total of 201 patients who required CBCT examinations as part of their dental diagnosis and treatment were enrolled in the present study. Overall, 596 healthy, untreated, well-developed maxillary and mandibular molar teeth (161 maxillary first molars, 157 maxillary second molars, 117 mandibular first molars, and 161 mandibular second molars) were examined by CBCT to establish the symmetry in root and canal anatomy between right and left sides in the same patient by evaluating the number of roots and root canals and the root canal configuration.

Results

Three separate roots with 3 separate canals was the normal anatomy of maxillary first and second molars. Most mandibular first and second molars had 2 separate roots, and the majority had 3 canals. In the present study, first molars, both maxillary and mandibular, exhibited greater asymmetry than the second molars. Maxillary first molars were found to be symmetrical in 71.1% of patients, whereas maxillary second molars were symmetrical in 79.6%. The remaining 28.9% and 20.4% of patients, respectively, showed asymmetry. Around 30% of the mandibular first molars and 20% of the mandibular second molars showed asymmetry.

Conclusions

The results of the present study reported a percentage of symmetry that varied from 70%–81%. These variations in symmetry should be taken in high consideration when treating 2 opposite molars in the same patient, because their anatomy may be different in up to 30% of the cases.     

The Incidence of Second Mesiobuccal Canals Located in Maxillary Molars with the Aid of Cone-beam Computed Tomography

Introduction

Many endodontic treatment failures in maxillary molars result from missed second mesiobuccal (MB2) canals. An MB2 canal orifice is present in as many as 95% of maxillary molars, but these canals are not always located during endodontic procedures. Additional tools, such as cone-beam computed tomographic (CBCT) imaging, may be needed to locate these canals in maxillary molars. Hence, the aims of this study were to investigate the frequency of use of CBCT imaging during the treatment of maxillary molars and to evaluate the influence of its use on the detection of MB2 canals.

Third molar angulation during and after treatment of adolescent orthodontic patients

The purpose of this study was to analyse the effect of premolar extraction therapy on third molar angulation during active treatment, and to test the significance of such changes on subsequent impaction of the third molars. Lateral cephalograms made before (T1) and after (T2) treatment and at long-term follow-up (T3) of 157 patients treated non-extraction (non-ex) or with extraction of four premolars (ex), all accurately diagnosed for impaction versus eruption of at least one third molar at T3, were evaluated. Linear regression models demonstrated that the maxillary third molars uprighted more from T1 to T2 (P < 0.05) and were less distally angulated at T2 (P < 0.01) in the ex than in the non-ex patients. No such differences were detected in the mandible (P > 0.05). The regression models also showed similar uprighting of the maxillary and mandibular third molars from T1 to T2 and similar angulation of the maxillary third molars at T2 in those patients with subsequent eruption and impaction (P > 0.05), but more mesially angulated mandibular third molars at T2 in the impaction patients (P < 0.01). Chi square testing demonstrated a higher frequency of distal tipping of the maxillary third molars from T1 to T2 in the impaction patients (P < 0.01), while mesial tipping from T1 to T2 of the mandibular third molars occurred with similar frequency in the two patient groups (P > 0.05). Chi square analysis also showed a higher frequency of greater than 30 degree distal angulation as well as an amount mesial angulation of the maxillary third molars at T2 (P < 0.01), and a higher frequency of greater than 40 degree mesial angulation of the mandibular third molars at T2 (P < 0.01) in patients with impaction than in those with eruption.     

Mandibular third molars as a risk factor for angle fractures: a retrospective study

Introduction  

Anecdotal reports suggest that the presence of mandibular third molars predispose the mandible to angle fractures. The purpose of this study was to evaluate the presence of mandibular third molars as a risk factor for angle fractures in patients with fractured mandibles.     

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography

As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published.

Objective

To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT).

Material and methods

In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠ PDM). DM, DP and ∠ PDM of the teeth with three or four root canals were analyzed and evaluated.

Results

In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠ PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º.

Conclusions

The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.     

Primary and Secondary Closure of the Surgical Wound After Removal of Impacted Mandibular Third Molars

Aim  

The present study attempted the evaluation of Primary and secondary closure techniques after removal of impacted third molars in terms of healing, post-operative pain and swelling.     

Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study

Introduction

The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging.

Methods

Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems.

Results

First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables.

Conclusions

Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.     

Indications for removal of impacted mandibular third molars: a single institutional experience in Libya

Aims  

To investigate the various indications for the removal of impacted lower third molars in a dental school in Libya.     

Risk factors associated with oroantral perforation during surgical removal of maxillary third molar teeth

Purpose

The relationship between radiographic findings and the occurrence of oroantral perforation is controversial. Few studies have quantitatively analyzed the risk factors contributing to oroantral perforation, and no study has reported multivariate analysis of the relationship(s) between these various factors. This retrospective study aims to fill this void.

Methods

Various risk factors for oroantral perforation during maxillary third molar extraction were investigated by univariate and multivariate analysis. The proximity of the roots to the maxillary sinus floor (root-sinus [RS] classification) was assessed using panoramic radiography and classified as types 1–5. The relationship between the maxillary second and third molars was classified according to a modified version of the Archer classification. The relative depth of the maxillary third molar in the bone was classified as class A–C, and its angulation relative to the long axis of the second molar was also recorded.

Results

Performance of an incision (OR 5.16), mesioangular tooth angulation (OR 6.05), and type 3 RS classification (i.e., significant superimposition of the roots of all posterior maxillary teeth with the sinus floor; OR 10.18) were all identified as risk factors with significant association to an outcome of oroantral perforation.

Conclusion

To our knowledge, this is the first multivariate analysis of the risk factors for oroantral perforation during surgical extraction of the maxillary third molar. This RS classification may offer a new predictive parameter for estimating the risk of oroantral perforation.

     

A Comparative Study: Efficacy of Tissue Glue and Sutures after Impacted Mandibular Third Molar Removal

Objective  

To compare the efficacy of cyanoacrylate (tissue glue) placement after surgical removal of impacted mandibular third molars.     

Three Root Canals in the Mesiobuccal Root of Maxillary Molars: Case Reports and Literature Review

Introduction

The knowledge of root canal anatomy is essential to ensure a successful outcome of surgical and nonsurgical root canal treatment. The aims of this article were to present 2 cases of maxillary molars with 3 mesiobuccal root canals and to review the available literature on this anatomic variation.

Methods

The first case described a nonsurgical root canal treatment of tooth #16 in a 29-year-old man with the aid of a dental operating microscope. In the second case, an extracted maxillary right first molar was scanned by a micro–computed tomographic system and reconstructed 3-dimensionally using modeling software.

Results

In both cases, the mesiobuccal root had 3 canals (type 3-2 in case I and type 3-3 in case II), whereas the distobuccal and palatal roots had a single canal. The literature review showed that the overall incidence of 3-canaled mesiobuccal roots in maxillary molars ranged from 1.3%–2.4% and that the most common root canal configuration was type 3-2.

Conclusions

Clinicians should always anticipate the presence of extra canals in maxillary molars and use all the available tools to locate and treat these.     

Delayed retrieval of a displaced maxillary third molar from infratemporal space via trans-sinusoidal approach: a case report and the review of the literature

Aim

The aim of this case report is to present the trans-sinusoidal pathway used to remove a displaced maxillary third molar from the infratemporal fossa and review the English literature regarding the techniques used.

Case report

A 21-year-old male patient was referred with the findings of an oroantral fistula on the left maxillary vestibular first molar region and slight restriction of mouth opening. The patient underwent a maxillary sinus surgery in order to remove a sinus retention cyst via Caldwell-Luc access in a dental clinic 4 years ago. A computerized tomography scan showed the inverted third molar to be located in the infratemporal fossa, just between zygomatic arch and lateral pterygoid plate. The tooth was accessed through the remaining lateral bone defect from the Caldwell-Luc approach of the lateral sinus wall. The bone defect was extended. The posterior bony wall of the maxillary sinus was removed via a surgical burr. After that, the displaced tooth was exposed. The tooth was mobilized via Warwick James elevator downwards and removed with a forceps.

Conclusion

Access for surgical removal of the tooth from the infratemporal fossa is not only difficult but also has potential for morbidity due to the structures running through it. Wide incision in the maxillary sulcus and blunt dissection are reported with lower success rates and usually necessitate a second intervention via extraoral route. Trans-sinusoidal approach might be an old fashioned but relatively successfully attempt in the removal of the upper third molars from the infratemporal fossa. Considering the time of removal, if no symptoms were present, it is beneficial to wait for a couple of weeks thus facilitating development of fibrous surrounding around the tooth.

     

Correlation between skeletal maturation and developmental stages of canines and third molars among Saudi subjects

Aims

The present study was designed to evaluate the efficacy of using the developmental stages of the canines and third molars to predict the timing of skeletal maturity in the Saudi population.

The surgical-orthodontic management of combined impacted maxillary second and third molars

Background

A correlation between impacted maxillary third molars on the eruption potential of the maxillary second molar has been identified. There is little published evidence available in the literature regarding a treatment modality for this presentation.

Aims 

The aim of this case series is to propose a joint surgical and orthodontic approach for the management of such cases.

Method 

A retrospective search of all patients treated for impacted second and third maxillary molars from 2014 to 2020 revealed 24 cases. Surgical planning was facilitated with the use of a CBCT to help orientate the teeth in 3-D and assess any associated pathology to nearby structures. Twenty-three cases were treated via surgical removal of the impacted third molar and subsequently monitored for spontaneous maxillary second molar eruption.

Conclusion

 All treated cases showed complete or partial spontaneous eruption followed by orthodontic repositioning if required.

     

A Cone-beam Computed Tomographic Study of Root and Canal Morphology of Maxillary First and Second Permanent Molars in a Thai Population

Introduction

Understanding tooth anatomy is crucial for effective endodontic treatment. This study investigated the roots and root canal morphology of maxillary first and second permanent molars in a Thai population using cone-beam computed tomographic (CBCT) imaging.

Acquisition of Anatomic Parameters Concerning Molar Pulp Chamber Landmarks Using Cone-beam Computed Tomography

Introduction

Cone-beam computed tomographic (CBCT) imaging is a valuable tool for endodontic therapy. The aim of this study was to verify whether clinical use of CBCT imaging can accurately acquire parameters concerning molar pulp chamber landmarks, which are important data to help start a successful access cavity and avoid iatrogenic furcation perforations.

Methods

Seventy CBCT images were used to measure 118 maxillary and 104 mandibular molars. The following vertical distances were measured: from the cusp tip/central fossa to the pulp chamber floor, to the pulp chamber ceiling, and to furcation; from the pulp chamber ceiling to furcation; from the pulp chamber floor to furcation; and the pulp chamber height. Measurements were read to the nearest 0.05 mm.

Results

The measurements were as follows: the pulp chamber floor to furcation (maxillary molar: 1.97 ± 0.58 [mean ± standard deviation, mm], mandibular molar: 2.24 ± 0.47), the pulp chamber ceiling to furcation (maxillary molar: 4.09 ± 0.68, mandibular molar: 3.78 ± 0.70), the central fossa to furcation (maxillary molar: 8.78 ± 0.79, mandibular molar: 8.53 ± 0.65), the central fossa to the pulp chamber floor (maxillary molar: 6.81 ± 0.83, mandibular molar: 6.29 ± 0.65), the central fossa to the pulp chamber ceiling (maxillary molar: 4.69 ± 0.59, mandibular molar: 4.75 ± 0.56); and pulp chamber height (maxillary molar: 2.12 ± 0.81, mandibular molar: 1.53 ± 0.68). Measurements showing the least standard deviation were the central fossa to furcation and the central fossa to the pulp chamber floor.

Conclusions

CBCT imaging may be used for precise clinical acquisition of the pulp chamber landmark measurements for molars thereby facilitating successful access cavity.     

Root Canal Preparation of Mandibular Molars with 3 Nickel-Titanium Rotary Instruments: A Micro–Computed Tomographic Study

Introduction

The aim of this study was to describe the canal shaping properties of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Universal (PTU; Dentsply Tulsa Dental Specialties, Johnson City, TN), and WaveOne (Dentsply Maillefer) nickel-titanium instruments in mandibular first molars by using micro–computed tomographic (micro-CT) scanning.

Methods

A total of 36 maxillary first molars with 2 separate mesial canals and 1 distal canal were selected and scanned preoperatively and postoperatively by using micro-CT scanning with a voxel size of 30 μm. Canals were prepared with PTU, PTN, and WaveOne systems under hypochlorite irrigation. The volume of the untreated canal; the volume of dentin removed after preparation; the amount of the uninstrumented area; and the transportation to the coronal, middle, and apical thirds of canals were measured. The preparation time and instrument failure were also recorded.

Results

Instrumentation of canals increased their volume and surface area. The distal canals had a significantly higher proportion of unprepared surfaces than mesial canals (P < .05). The PTN system produced less transportation than the WaveOne and PTU systems in the apical third of the mesial canals (P < .05). There was no significant difference on apical transportation in distal canals among the 3 instrument systems. Instrumentation with WaveOne was significantly faster than with the other 2 instruments (P < .05).

Conclusions

The PTN, PTU, and WaveOne instruments shaped root canals in mandibular first molars in vitro without significant shaping errors. The curved canals prepared using PTN had less apical transportation than the canals prepared using WaveOne and PTU.     

Mesiodistal root angulation of permanent teeth in children with mixed dentition and normal occlusion

Objective

There is little information regarding the mesiodistal angulation of permanent teeth in mixed dentition. The aim of this study was to evaluate mesiodistal root angulation of permanent incisors, canines and first molars of 100 Brazilian children, using a new horizontal reference plane based on the midpoint of the intercuspation of primary canines and permanent first molars in panoramic radiographs during the mixed-dentition phase.

Material and methods

Children were equally divided between the genders with a mean age of 8.9 years (SD=0.76), normal occlusion and no eruptive disturbances.

Results

The angulation of the permanent maxillary first molars was close to the vertical, whereas the mandibular molars presented approximately 25 degrees of distal root angulation. The maxillary canines were the most distally angulated teeth, whereas the permanent mandibular canines were vertically positioned. The evaluation of the anterior maxillary area showed vertical position of permanent lateral, and central incisors with a slight distal angulation, whereas the permanent mandibular incisors tended to a mesial radicular convergence.

Conclusions

The proposed reference line could be useful in mixed dentition root angulation evaluation; there was a slight asymmetry in the mesiodistal angulation among homologous teeth, and also a small variation between the male and the female groups, but no difference between 8-and 10-year-old children.