Lower Third Molar Research Articles

Augmented Reality-Guided Extraction of Fully Impacted Lower Third Molars Based on Maxillofacial CBCT Scans

(1) Background: This study aimed to integrate an augmented reality (AR) image-guided surgery (IGS) system, based on preoperative cone beam computed tomography (CBCT) scans, into clinical practice. (2) Methods: In preclinical and clinical surgical setups, an AR-guided visualization system based on Microsoft’s HoloLens 2 was assessed for complex lower third molar (LTM) extractions. In this study, the system’s potential intraoperative feasibility and usability is described first. Preparation and operating times for each procedure were measured, as well as the system’s usability, using the System Usability Scale (SUS). (3) Results: A total of six LTMs (n = 6) were analyzed, two extracted from human cadaver head specimens (n = 2) and four from clinical patients (n = 4). The average preparation time was 166 ± 44 s, while the operation time averaged 21 ± 5.9 min. The overall mean SUS score was 79.1 ± 9.3. When analyzed separately, the usability score categorized the AR-guidance system as “good” in clinical patients and “best imaginable” in human cadaver head procedures. (4) Conclusions: This translational study analyzed the first successful and functionally stable application of the HoloLens technology for complex LTM extraction in clinical patients. Further research is needed to refine the technology’s integration into clinical practice to improve patient outcomes.

The impact of flap design on swelling, trismus, and pain after the lower third molar surgery: Buccal triangular flap vs. envelope flap

Background/Aim. Swelling, trismus, and pain (STP) are the most common complications that occur after the surgical extraction of impacted lower third molars (LTM). Buccal triangular and envelope flaps are the two most commonly used mucoperiosteal flaps in LTM surgery. The aim of this study was to compare the possible impact of these two types of flaps on the occurrence and intensity of postoperative STP after the surgical extraction of impacted LTMs. Methods. The study included 30 adult patients of both genders, with fully impacted LTMs in vertical position according to Winter classification and class I or II, and position A or B, according to Pell and Gregory classification. All patients were randomly divided into two groups depending on the type of the applied mucoperiosteal flap (triangular or envelope type). The degree of edema, interincisal distance (trismus), and the level of pain were evaluated preoperatively and at each follow-up (on the first, second, and seventh day postoperatively). Results. No statistically significant difference was found among the examined groups in terms of STP reduction in the postoperative period (p > 0.05). Conclusion. The choice of mucoperiosteal flap design, buccal triangular or envelope, during the surgical extraction of impacted LTMs has no impact on the intensity of postoperative STP.

High- Risk Factors Associated with Inferior Alveolar Nerve Injury Following Removal of the Third Molars: A Preliminary Study

PURPOSE: This study aims to determine the incidence of inferior alveolar nerve (IAN) injury following the extraction of the lower third molars (LTMs) and to identify the demographic, radiographic, and intra-operative risk factors associated with this complication. MATERIALS & METHODS: Fifty LTMs from 47 patients were included in this prospective clinical study. Demographic data and intra-operative parameters including operation time, bone removal and duration, excessive bleeding and IAN exposure were recorded. Bone retention, anatomical position of LTMs (Pell&Gregory and Winter classification) and 5 radiographic criteria proposed by Rood and Shehab were evaluated on panoramic images, whereas the distance between roots and the inferior alveolar canal (IAC), the cortication status of IAC, and the buccolingual position of IAC were examined on CBCT images. Chi-square test was used to compare the presence of IAN injury with variables. A p-value < 0.05 was considered as statistically significant. RESULTS: The incidence of temporary IAN injury was 6% among study population. No permanent IAN injury was observed. Excessive bleeding (p=0.007), IAN exposure (p=0.007), the lingual position of IAC (p=0.035) and dumbbell-shaped IAC (p=0.002) were found to be associated with increased risk of temporary IAN injury. CONCLUSION: Identification of high-risk factors is essential for predicting the risk of IAN injury, and determining the most convenient treatment plan for each case. Further studies with larger study samples are needed both to confirm the risk factors that are proposed in the present study and to identify the other potential ones.

Effects of Leukocyte-Platelet-Rich Fibrin (L–PRF) on Pain, Soft Tissue Healing, Growth Factors, and Cytokines after Third Molar Extraction: A Randomized, Split-Mouth, Double-Blinded Clinical Trial

This study assessed the effects of leukocyte-platelet-rich fibrin (L–PRF) on soft tissue healing and the correlation with the local concentration of growth factors (GF) and cytokines in the dental socket of lower third molars. Forty lower-third molars (20 participants) were included in this randomized, double-blinded, split-mouth study. After extractions, randomized sides received alveolar filling with L–PRF on one side and a natural blood clot on the other side. The pain was assessed for up to seven days and soft tissue healing (Landry index) for 14 days post-extraction. Swabs were collected from the surgical sites for GF and cytokine assessment by flow luminometry. Participants reported lower postoperative pain on the sides grafted with L–PRF, which also presented increased tissue healing scores (p < 0.05). There were increased levels of all GFs and several cytokines at the L–PRF site at day one, while vascular endothelial growth factor (VEGF), IL–10, and IL1–RA remained higher throughout for seven days (p < 0.05). VEGF concentration at L–PRF sites correlated positively with the participants’ blood platelet content (ρ = 0.769). PDGF correlated negatively with pain experience on days 2 and 3, and positively with soft tissue healing scores, while FGFb presented a weak correlation with a reduction of pain on day 3. The use of L–PRF improves the soft tissue healing process and decreases postoperative pain after the third molar extractions, which correlates with an increase in the local concentration of growth factors such as PDGF and FGFb.

Single-channel electroencephalography and its associations with anxiety and pain during oral surgery: a preliminary report

BackgroundThis study aimed to assess the course of anxiety and pain during lower third molar (LTMo) surgery and explore the role of mobile and single-channel electroencephalography under clinical and surgical conditions.MethodsThe State-Trait Anxiety Inventory (STAI), Corah's Dental Anxiety Scale (DAS), and Interval Scale of Anxiety Response (ISAR) were used. The patient self-rated anxiety (PSA), the pain felt during and after surgery, EEG, heart rate (HR), and blood pressure (BP) were assessed.ResultsThe Attention (ATT) and Meditation (MED) algorithms and indicators evaluated in this study showed several associations. ATT showed interactions and an association with STAI-S, pain during surgery, PSA level, HR, and surgical duration. MED showed an interaction and association with DAS, STAI-S, and pain due to anesthesia. Preclinical anxiety parameters may influence clinical perceptions and biological parameters during LTMo surgeries. High STAI-Trait and PSA scores were associated with postoperative pain, whereas high STAI-State scores were associated with more pain during anesthesia and surgery, as well as DAS, which was also associated with patient interference during surgery due to anxiety.ConclusionsThe findings suggest that single-channel EEG is promising for evaluating brain responses associated with systemic reactions related to anxiety, surgical stress, and pain during oral surgery.

Surgically concerned anatomy of roots of lower third molar

Background and Objectives: Root anatomy of lower third molar (LTM) may have variable patterns. Root number, shape and curvature all affecting the process of surgery. To determine frequency of different root patterns of LTM. Patients and methods: Retrospectively, a total of 196 orthopantomograms of department of radiology were evaluated for LTM root number and curvature of roots. Results: two roots 173 (88.26%) one root 22 (11.74%). All single rooted teeth showed no curvature. Among two rooted teeth the study figured out that majority of roots not fused but converge 134 (77.45%), fused together 20 (11.5%), not fused but diverge 11 (≈ 6%), not fused with root curvature. Conclusion: Majority of LTM have two or more roots, they are convergent or divergent. Root anatomy evaluation before surgery is mandatory.

Epidermal Growth Factor Receptor (EGFR) Expression and Incidence of Cystic Changes in Asymptomatic Dental Follicles in Smoking Patients

Background: Smoking is a well-known predisposing factor for pathological changes in oral tissues. Epithelial proliferation due to smoking is caused by the increased expression and activation of epidermal growth factor receptor (EGFR), which is a protooncogen. Aims: The objective of this study was to evaluate Epidermal Growth Factor Receptor (EGFR) expression and intensity and the incidence of histologically diagnosed cystic changes in asymptomatic impacted lower third molar (ILTM) follicles of smoking and non-smoking patients. Materials and Methods: A hundred dental follicles obtained from asymptomatic ILTMs were examined histopathologically and immunohistochemically using antibody against EGFR. After initial microscopic analyses, 18 specimens were excluded from the study because of lack of epithelium. The final EGFR expression intensity score of samples was determined by multiplying the percentage of positively stained cells by the staining intensity. Results: Cystic changes were detected with microscopic evaluation. In the smoking group, the relation between EGFR scores and cystic changes were found statistically significant (p<0.05). The relation of age and EGFR scores that showed cystic changes in the smoking group was also found statistically significant (p<0.05). Conclusion: Asymptomatic ILTMs of the smoker patients may be suspected for the higher possibility of cystic changes compared with the nonsmokers. Smoking may be considered as a factor for the decision of removal of an asymptomatic ILTM. Key Words: EGF Receptor, cystic changes, dental follicles, smoking

The value of CBCT in identifying the risk of nerve injury and the management of lower third molars

Background: Radiographic evaluation of impacted lower third molars (LTMs) is essential for careful treatment planning. This can be achieved using various imaging modalities such as CBCT which provides 3-dimensional views for precise identification of the potential risk of inferior alveolar nerve injury (IANI).

Clinical assessment of position of impacted lower third molars and their indications for extraction

The purpose of this study was to assess the position of impacted lower thirdmolars, the indications for extraction, and the post-operative complications. Recordsof patients who attended Misan general hospital between March 2008 and April 2009for surgical removal of mandibular third molars.The angulation type and depth of impaction were determined by reviewing theorthopantomograms. A total of 140 impacted teeth were surgically extracted from 132patients (69 males, 63 females). The reasons for extraction include recurrentpericoronitis (55%) followed by caries (25%) and prophylactic purposes (20%).Mesioangular impactions accounted for (49.29 %) and Level 1 position ofimpaction accounted for (65%) of extractions. 40 complications (28.57%), includingpersistent pain and swelling, infection, dry socket, Trismus and ulceration werereported . Persistent pain and swelling was the most common complications followedby infection.There was no significant relationship between the angulation, level of impactionand the occurrence of complications. Mesioangular type and Level A position ofimpaction were the most common impaction. Although the association was notsignificant, high frequency of post-operative complications was observed inmesioangular, horizontal and level A position of impaction.

CBCT evaluation of the tridimensional relationship between impacted lower third molar and the inferior alveolar nerve position.

The aim of this study is to evaluate if the statistical significant relations between the measures taken exists or not and to show how the 3D reconstruction could be help the oral surgeon in all those instances in which it may have a direct impact on the planning of the surgical steps. Thanks to use of NobelClinician™ Software it was possible to analyze 200 mandibular tomography computerized, random selected, and create a 3D reconstruction of mandibular bone, point out dental structure of wisdom tooth and the way of IAN. Statistical analysis was performed using the Statistical Package for Social Sciences. One way ANOVA test was used to measure the association between each independent variable and the outcome variable, followed by the post-hoc least significant difference (LSD) test for intergroup differences. Two independent variables were significant predictors for risk to have the distance 0 mm from IAN to apex: "Ramus relationship/space available" and "depth". The 3D reconstruction software provide surgeons with an additional planning tool, offering: immediate and neat visualization of the noble structures that have to be respected and their localization in the three spatial planes; the exact morphology of the relevant root apex; a 360° view of the relationship between the IAN and the third molar and the exact point in which the root is in relationship with the canal.

Electromyographic Study of the Masseter Muscle After Low-Level Laser Therapy in Patients Undergoing Extraction of Retained Lower Third Molars

La cirugia para extraccion del tercer molar mandibular retenido es uno de los procedimientos mas realizados en el campo de la cirugia maxilofacial. Durante este procedimiento, el trauma quirurgico puede causar dano a la funcion de los musculos involucrados en los movimientos mandibulares, entre ellos el musculo masetero. Con el objetivo de acelerar la recuperacion postoperatoria, son utilizados muchos recursos de fisioterapia, incluyendo la terapia con laser. El objetivo de este estudio fue analizar la actividad electrica del musculo masetero tratado con laser de baja intensidad (LBI) despues del trauma quirurgico. Se realizaron evaluaciones del musculo masetero en una muestra de 60 pacientes, a traves de electromiografia de superficie en cuatro momentos: preoperatorio inmediato, postoperatorio a los 7, 14 y 21 dias. Los pacientes fueron divididos en dos grupos: 1 - grupo no tratado con LBI en el postoperatorio; 2 - grupo tratado con LBI (810 nm; 10 J/cm2) en el postoperatorio inmediato y a los 3, 6 y 9 dias tras cirugia. Al septimo dia tras cirugia el 23,3 % de los pacientes del grupo tratado con LBI presentaron recuperacion de su actividad muscular equivalente a lo presentado en el preoperatorio inmediato, frente a solo el 3,3 % del grupo no tratado. En el dia 14, el 73,3% de los pacientes tratados presentaron rehabilitacion funcional, frente al 6,7% del grupo no tratado y en el vigesimo primer dia, el 80% frente al 10% del grupo no tratado. En el dia 14 postoperatorio la actividad electrica del musculo masetero tratado con LBI despues del trauma quirurgico fue compatible con una condicion de recuperacion funcional completa. Los hallazgos de este estudio electromiografico indicaron que el LBI es un eficiente metodo fisioterapico para estimular la recuperacion funcional del musculo masetero tras cirugia de terceros molares mandibulares retenidos.

Prevention of localized osteitis in mandibular third-molar sites using platelet-rich fibrin.

Purpose. To review our experience utilizing platelet rich fibrin (PRF), which is reported to aid in wound healing of extraction sites, for the prevention of localized osteitis following lower third-molar removal. Materials and Methods. PRF was placed in the mandibular third-molar extraction sites, 200 sites total, on 100 consecutive patients treated in our practice, by the authors. The patients were managed with standard surgical techniques, intraoperative IV antibiotic/steroid coverage, and routine postoperative narcotic analgesics/short-term steroid coverage. All patients were reevaluated for localized osteitis within 7–10 days of the surgery. A comparison group consisted of 100 consecutive patients who underwent bilateral removal of indicated mandibular wisdom teeth and did not receive PRF placement within the lower third molar surgical sites. Results. The incidence of localized osteitis (LO) following removal of 200 lower third molars with simultaneous PRF placement within the extraction site was 1% (2 sites out of 200). The group of patients whose mandibular 3rd molar sockets were not treated with PRF demonstrated a 9.5% (19 sites out of 200) incidence of localized osteitis. The latter group also required 6.5 hours of additional clinical time to manage LO than the study group who received PRF. Conclusions. This retrospective review demonstrated that preventative treatment of localized osteitis can be accomplished using a low cost, autogenous, soluble, biologic material, PRF, that PRF enhanced third-molar socket healing/clot retention and greatly decreased the clinical time required for postoperative management of LO.

Comparative study of the effect of dexamethasone injection and consumption in lower third molar surgery

The aim of this study was to compare the effect of intramuscular (IM) injection and consumption of 8mg dexamethasone in patients after lower third molar (LTM) surgery. 20 healthy Thai patients, average age 20 years, with bilateral LTM removal were recruited for this study, a double blinded, paired sample clinical trial. The washout period was 1 month after the first operation. Clinical assessment of facial swelling, pain and maximum mouth opening were measured before and after operation for 7 days. No significant difference was found in facial swelling between IM injection and consumption of 8mg dexamethasone after LTM surgery (paired t test P>0.05). The visual analogue scale scores for pain assessment showed no significant difference between IM injection and consumption of dexamethasone (paired t test P>0.05). The results conclude that IM injection or consumption of dexamethasone after LTM surgery can be used to control facial swelling, pain and trismus.

A new method for relative Sr determination in human teeth enamel.

We present a new method to determine Sr/Ca changes in hard dental tissues based on laser ablation and spectroscopic detection. By using femtosecond Laser Induced Breakdown Spectroscopy (fs-LIBS), we micro mapped the relative amount of strontium in the enamel of three human lower third molar. We also analyzed the Sr/Ca ratio along the striae of Retzius. Results show that microlibs allows detection of variation in relative Sr/Ca ratio through enamel. The same values of Sr/Ca ratio were found along a single stria. The method has a precision better than 95% and is sensitive enough to detect Sr/Ca ratio variations among striae and within stria. Fs-LIBS generates information in a fast and simple way that can be used by non-specialists to make inferences about diet or mobility in human populations and fossil hominids.

Cone beam tomography evaluation of lingual cortical mandibular defect diagnosed as Stafne bone cavity

Introduction: Mandibular lingual bone depressions are considered tobe developmental anomalies known as Stafne bone cavity. The purposeof the present report is to describe the characteristics of classic Stafnebone cavity in molar region evaluated by cone beam computedtomography (CBCT). Case report: A male patient, 27 years old, wassubmitted to CBCT to evaluation of the relation between the right lowerthird molar roots and mandibular canal and the unilateral cystic imagefound in the panoramic radiographic below the mandibular canal in theright molar area. It was used a gray scale of 12 bits and voxel of 0.2 mm. The CBCT showed fine images of the Stafne bone cavity. In the presentcase, periodic clinical and radiological controls were the therapeuticoption. In atypical cases or in doubtful diagnosis, surgical interventionand anatomopathological examination may be indicated. Conclusion:Although the diagnosis of a Stafne bone cavity can often be establishedwith plain radiographs, confirmatory tests are sometimes required. Inthese situations, the diagnosis can be confirmed with CBCT.

Radiographic signs associated with inferior alveolar nerve damage following lower third molar extraction

The aim was to carry out a literature review of preoperative radiographic signs in orthopantomography (OPG) and computed tomography (CT) related with the risk of inferior alveolar nerve damage during the surgical extraction of lower third molar (LTM). A search was made on PubMed for literature published between the years 2000 and 2009. In the reviewed literature, radiographic signs in the OPG that indicate a relationship between the LTM and the inferior alveolar canal are considered a risk factor for nerve damage. These signs are darkening and deflection of the root, and diversion and interruption in the white line of the canal. In the majority of these studies, the routine use of CT is not justified, and is only recommended when radiographic signs appear in the OPG that demonstrate a direct anatomical relationship between the LTM and the canal. In the CT, the absence of cortical bone in the canal implies a contact between the root of the LTM and the canal, and is related with the presence of some radiographic signs in the OPG. Some studies demonstrate that despite the absence of cortical bone, the risk of lesion or exposure of the nerve during the extraction of LTM was low.

Mandibular impacted third molar Surgery and Drains: a review of the literature.

Pain, swelling and trismus are the most common causes of discomfort and postoperative morbidity after the surgical removal of impacted lower third molars under local anesthesia. A review of literature shows that the existence of these postoperative variables after the surgical removal of impacted lower third molar are well known and could lead to a reduction in the postoperative quality of life of patients. Reducing or minimizing these postoperative variables seems a laudable goal especially if wound healing is not compromised. Several studies carried out have not pointed on any systemic or local agent used without any adverse effect. Oral surgeons have used drains after the surgical removal of mandibular impacted third molars to minimize postoperative morbidity with varying degrees of success. The use of a drain in association with primary suture after the surgical removal of the impacted lower third molars allows the patient to experience a more comfortable postoperative period in relation to pain, swelling and trismus, because it permits the drainage of fluids located in the tissue spaces. The purpose of this study is to review the effects of drains after the surgical removal of impacted lower third molar so that oral surgeons carrying out lower third molar extraction may be properly informed to consider the use of drains to minimize the postoperative discomfort. Keywords : third molar surgery-morbidity-use of drain Journal of College of Medicine Vol. 12 (2) 2007: pp. 80-84

Postoperative analgesia after lower third molar surgery: contribution of the use of long-acting local anesthetics, low-power laser, and diclofenac

Postoperative pain is a common phenomenon after surgical extraction of lower third molars (LTM), and its successful control is an essential part of routine oral surgery. The aims of the study were twofold: (1) to evaluate the postoperative analgesic efficacy, comparing long-acting and intermediate-acting local anesthetics; and (2) to compare the use of low-power laser irradiation and the nonsteroid anti-inflammatory drug diclofenac, which are claimed to be among the most successful aids in postoperative pain control. A twofold study of 102 patients of both sexes undergoing surgical extraction of LTM was conducted. In the first part of the study, 12 patients with bilaterally impacted LTMs were treated in a double-blind crossover fashion; local anesthesia was achieved with 0.5% bupivacaine plain or 2% lidocaine with 1:80.000 epinephrine. In the second part of the study, 90 patients undergoing LTM surgical extraction with local anesthesia received postoperative low-power laser irradiation (30 patients) and a preoperative single dose of 100 mg diclofenac (30 patients), or only regular postoperative recommendations (30 patients). The results of the first part of the study showed a strikingly better postoperative analgesic effect of bupivacaine than lidocaine/epinephrine (11 out of 12; 4 out of 12, respectively, patients without postoperative pain). In the second part of the study, low-power laser irradiation significantly reduced postoperative pain intensity in patients premedicated with diclofenac, compared with the controls. Provided that basic principles of surgical practice have been achieved, the use of long-acting local anesthetics and low-power laser irradiation enables the best postoperative analgesic effect and the most comfortable postoperative course after surgical extraction of LTMs.

A comparative study of the effect of different third molar impactions on postoperative morbidity following lower third molar surgery

Background : The surgical removal of impacted lower third molar is one of the most frequently performed procedures in oral and maxillofacial surgery and represents a standard operation. Patients' complaints of pain, swelling and limitation in mouth opening associated with inflammatory response following lower third molar surgical extraction is an important factor affecting their daily life. The type of molar impaction has been associated with the increased postoperative morbidity following surgical removal. Objectives : The aim of this study is to compare the effect of different molar impactions according to George Winter on postoperative pain, swelling and trismus, which occur after lower third molar surgery. Patients and Methods : A comparative study of the effect of different lower third molar impactions on postoperative pain, swelling and trismus was carried out among 100 patients of both gender attending the oral and maxillofacial surgery unit of University of Nigeria Teaching Hospital, Enugu between January 2004 and February 2005. The molar impactions were mesioangular; 35, vertical; 26, horizontal; 23 and distoangular; 16. There were 40 (40%) males and 60 (60%) females all between the ages of 18-40 years. Pain, swelling and trismus were evaluated at 24 hours, 72 hours and 5 days postoperatively. The measurements obtained were recorded and converted to relative values, which provided numerical data for the comparative analysis. Results : The result of the study showed that mesioangular impaction had the highest reduction in all the postoperative variables followed by the horizontal impaction at all the evaluation periods while distoangular impaction had the least. Conclusion : The type of impaction according to Winter is associated with postoperative morbidity after lower third molar surgery. Distoangular impaction tends to have high rate of postoperative morbidity than others. This calls for adoption of extra measures in minimizing these postoperative variables by oral surgeons carrying out third molar surgery especially during distoangular disimpaction. Keywords : third molar surgery; different impactions; morbidity. Journal of College of Medicine Vol. 11 (2) 2006: 82-87

A three-dimensional finite element analysis on the effect of seven different occlusions on TMJ

To investigate the effects of tooth apical stress changes caused by different types of occlusion on the TMJ stresses. The apical stresses measured from photo-elastic experiments (2 Kg centric vertical loading to seven types of occlusions separately) were applied to the established 3D finite elemental model. The stress distributions on condyle, superfacial cartilage of condyle and TMJ disc were compared. (1) The stress on both anterior surface of condyle and its superfacial cartilage and on the intermediate band of disc were mainly compressive, while the stress on both posterior surface of condyle and its superficial cartilage and on the posterior band of disc were mainly tensile (P < 0.01). (2) The values of TMJ stresses of models with flat surface occlusion, distal occlusion, unilateral partial molar teeth cross bite, and occlusion with right second and third molar tooth missing were different to some extent from that with normal occlusion, among which the TMJ stress from the flat surface occlusion differed most significantly (P < 0.01). The TMJ stresses of models with unilateral upper third molar hyper-eruption occlusion and unilateral lower third molar hyper-eruption occlusion did not significantly differ from that with normal occlusion. Changes of apical principle stress resulted from different types of occlusions during centric biting have effects to some extent on TMJ stress quantitatively but not qualitatively.