Lingual Retraction Research Articles

Clinical application of a lingual retractor with temporary anchorage devices (TADs) for patients with lip protrusion and anterior open bite

Anterior open bite (AOB) is considered one of the most difficult malocclusions to correct and achieve successful and stable results. Various treatment approaches have been proposed for the treatment of AOB in adults. Intrusion of the entire maxillary dentition is necessary for AOB patients with severe incisor exposure. In previous reports, a labial appliance with temporary anchorage devices (TADs) implanted in various positions has been used to achieve total intrusion of the maxillary dentition. This article describes the design and biomechanics of an anteroposterior lingual retractor (APLR) to attempt retraction of anterior teeth and total intrusion of maxillary dentition after premolar extraction in patients with both lip protrusion and AOB and the functions of each component of APLR is considered. When force is applied between the anterior lever arm of the APLR and a TAD in the midpalatal area, the anterior teeth are intruded and retracted with torque control. Because the direction of the APLR force and the guide bar are not parallel, intrusive force is generated in the posterior teeth. Due to this total intrusion of the maxillary dentition, the mandible is rotated counterclockwise, improving AOB with severe incisor exposure. Various cases are presented in which APLR was applied to AOB patients, and the clinical considerations behind the treatment are explained in detail.

The success rates and outcomes of mandibular third molar coronectomy: 167 cases

PurposeThe purpose of this study was to assess success rates and to report complications of coronectomy of mandibular third molars (M3M), including intra-operative failure, pain, infection, dry socket, inferior dental alveolar (IAN) and lingual nerve (LN) injuries and re-operation rates.MethodsRetrospective analysis of 167 coronectomies completed between January 2017 to December 2022 was undertaken.ResultsThe success of coronectomy was 93%. Intra-operative failure was reported to be 3.6% (n = 8). Complications accounted for pain (15%, n = 24), infection (9%, n = 15) and dry socket (3.6%, n = 6). Three patients required removal of M3M root at 3 months (n = 2) and 24 months (n = 1), accounting for 1.8% re-operation rate. A total of number of patients who suffered a nerve injury was 12; three of these were permanent (LN – 1.2%, n = 2; IAN – 0.6%, n = 1), nine were temporary (IAN – 1.2%; n = 2, LN – 2.4%; n = 4; site not specified – 1.8%, n = 3). No patients with intra-operative failure and re-operation suffered IAN or LN injury post-operatively.ConclusionCoronectomy offers a successful strategy for management of high risk M3M. The treatment outcomes can be improved with careful case selection and adjusting surgical technique, including assessment of root morphology, incomplete crown sectioning technique and avoidance of lingual retraction. Reporting of coronectomy success as a factor of surgical outcome, presence or absence of permanent IAN injury, persistent symptoms or any other long-standing complications (such as LN injury), and the need for re-operation accounting for root migration status may be a useful tool to measure coronectomy outcomes.

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

BackgroundThe aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances.Methods3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance.ResultsIn the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models.ConclusionsIn the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

Incidence of lingual nerve damage following surgical extraction of mandibular third molars with lingual flap retraction: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to examine more recent data to determine the extent of lingual nerve injury (LNI) following the surgical extraction of mandibular third molars (M3M). A systematic search of three databases [PubMed, Web of Science and OVID] was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The inclusion criteria encompassed studies on patients who underwent surgical M3M extraction using the buccal approach without lingual flap retraction (BA-), buccal approach with lingual flap retraction (BA+), and lingual split technique (LS). The outcome measures expressed in LNI count were converted to risk ratios (RR). Twenty-seven studies were included in the systematic review, nine were eligible for meta-analysis. Combined RR for LNI (BA+ versus BA-) was 4.80 [95% Confidence Interval:3.28-7.02; P<0.00001]. The prevalence of permanent LNI following BA-, BA+ and LS (mean%±SD%) was 0.18±0.38, 0.07±0.21, and 0.28±0.48 respectively. This study concluded that there was an increased risk of temporary LNI following M3M surgical extractions using BA+ and LS. There was insufficient evidence to determine whether there is a significant advantage of BA+ or LS in reducing permanent LNI risk. Operators should use lingual retraction with caution due to the increased temporary LNI risk.

Clinical Application and Biomechanics of Various Lingual Retractors with Temporary Skeletal Anchorage Devices: A Narrative Review

The lingual retractor is an appliance with esthetic advantages and biomechanical superiority in the retraction of anterior teeth, when used in combination with temporary skeletal anchorage devices (TSADs). These appliances can address the patients’ chief complaint during the early stages of bialveolar protrusion treatment. This narrative review presents the clinical applications and biomechanics of various lingual retractors with TSADs.This review includes all research and case reports related to various lingual retractors such as the C-lingual retractor (CLR), double J retractor (DJR), and antero-posterior lingual retractor (APLR). Anterior torque and vertical control can be achieved with all three types of lingual retractors by changing the length of the lever arms and the position of the TSADs. Torquing springs in DJR are designed to slide along palatal mini-implants or to apply intermaxillary elastics to counteract retroclination of the incisors during space closure. APLR allows three-dimensional control of the anterior tooth movement with anterior lever arms, guide bars, posterior tubes, and position of TSADs. Various lingual retractors with TSADs are effectively proper anterior torque and vertical control.

Comparison of naproxen and combination therapy (naproxen and gabapentin) in post extraction pain relief.

Objective: To evaluate the efficacy of using combination drug treatment to relieve post extraction pain of impacted mandibular third molar by using Naproxen plus Gabapentin versus Naproxen alone. Study Design: Randomized Control study. Setting: Dental Clinic OPD of Bhitai Dental and Medical College, Sindh, Pakistan. Period: 1st December 2018 to 30th May 2019. Material &amp; Methods: The procedure for extraction was carried out under Local Anaesthesia (2% lignocaine hydrochloride with 1:100,000 adrenaline) at dental clinic OPD of Bhitai Dental and Medical College. Some extractions were performed in Closed Extraction technique while in some patients standard surgical procedure was used which consist of triangular muco – periosteal flap on buccal surface and lingual retraction of soft tissue followed by bone removal. For Pre – Operative and 24-Hour Post – Operative Pain status assessment Visual Analogue Scale and Wong Baker’s Face Pain Rating Scale. Results: Combination therapy (Naproxen and Gabapentin) was effective in significant pain reduction at 12 Hour and 24-Hour Post Extraction period. With 26 patients out 31 presented with Pain Scale of 0 on combination therapy while only 3 out of 31 for naproxen alone after 24 hours. All patients received a single dose of study medicines from the hospital pharmacy. In demographic data, there were 47% (n=29) males and 53% (n=33) females with mean age group of 27.89. Comparing the pain response between the genders, males presented slightly faster pain relief with time as to the females. Conclusion: Enhanced effect of combination therapy of naproxen with gabapentin in reducing post extraction pain of impacted mandibular third molar with respect to naproxen alone.

Cone-beam CT evaluation of the effect of indirect anchorage of mini-screw assisted clear aligner on molar distalization

Objective: To evaluate the effect of indirect anchorage with mini-screw assisted clear aligner on molar distalization. Methods: Twenty-six adult patients [12 males and 14 females, aged 19 to 31 years, mean age (26.4±4.2) years], who were treated in the Department of Orthodontics, the Affiliated Stomatological Hospital of Nanchang University between January 2018 and September 2021, were included. All the patients were treated with clear aligner and mini-screw indirect anchorage to distalize maxillary molars. In the stage of molar distalization, the mini-implants were implanted between the buccal roots of the maxillary first molar and the second premolar, and rigidly connected to the maxillary second premolar as anchorage reenforcement. Until the first molar had distally moved to the designated position, the mini-implants were transferred to the buccal area between the first and the second molars and similar device was connected to the first molar. Cone-beam CT (CBCT) images were taken before the treatment (T0), at the maxillary first molar distally moved to the designated position (T1), and at the anterior teeth alignment finished (T2). The CBCT data were imported into Mimics 20.0 software for three-dimensional reconstruction. After correcting the head position, each reference point was determined in the multi-plane reconstruction view. The bilateral porion, the right orbitale, the nasion, and the anterior nasal spine were selected as reference points to construct the three-dimensional space coordinate system. The positions of the first molar, the second premolar, and the incisor were analyzed three-dimensionally. The three-dimensional position changes of maxillary first molars and maxillary second premolars during the stages of T0-T1, T1-T2, T0-T2, and the mesiodistal and vertical position changes of maxillary central incisors were analyzed. The statistical analysis was carried out using a one-way repeated measures ANOVA. Results: There was a significant difference in the sagittal position changes of the root and cusp of the maxillary central incisors among three time points (F=24.84, P<0.001; F=27.66, P=0.001), but no difference was observed between T0 and T1 (P>0.05). There was a significant difference in lingual retraction of the maxillary central incisor root [(2.17±0.42) mm] and cusp [(1.81±0.28) mm] between T1 and T2 (P<0.05). A significant difference was noted in the sagittal position changes of the root and crown of the maxillary second premolars among three time points (F=17.16, P=0.001; F=57.99, P<0.001). However, no statistical difference was detected between T0 and T1 (P>0.05) and the difference in maxillary second premolar distalization [root (1.95±0.42) mm, cusp (2.53±0.33) mm] was observed between T1 and T2 (P<0.05). There was a statistically significant difference in the sagittal position changes of the root and the crown of the maxillary first molar among three time points (F=9.37, P=0.002; F=140.26, P<0.001). The difference in the maxillary first molar distalization [crown (3.51±0.30) mm, root (1.98±0.25) mm] between T0 and T1 was significant (P<0.05). However, no significant difference in the sagittal position of the maxillary first molars was observed between T1 and T2 (P>0.05). There was a statistically significant difference in the vertical position of the center point of the root in maxillary first molar among three time points (F=59.06, P<0.001), while (2.28±0.24) mm of intrusion between T0 and T1 was exhibited (P<0.05). However, no significant difference was found in the vertical position of the maxillary first molars between T1 and T2 (P>0.05). There was no significant difference in other measurements among three time points (P>0.05). Conclusions: The effect of indirect anchorage with mini-screw-assisted clear aligner on molar distalization was positive.

Surgical techniques for the removal of mandibular wisdom teeth.

Surgical techniques for the removal of mandibular wisdom teeth.

Systematic review of lingual nerve retraction during surgical mandibular third molar extractions.

The lingual nerve is at risk of damage during mandibular third molar (M3M) surgery. Current trends to avoid lingual retraction and prevent injury to the nerve run counter to the surgical principles of locating and protecting important structures. To our knowledge, the last review of this subject only considered repurposed lingual retractors such as the Howarth. Other studies have reported the use of purpose-built retractors with improved outcomes for lingual nerve injuries. This systematic review aims to assess the current view regarding lingual nerve retraction in M3M surgery. A search of PubMed and Web of Science using the key words "lingual", "nerve", "retractor", and "retraction" returned 118 results, 10 of which were selected for inclusion (nine original research papers and one systematic review). The data comprised 16,133 M3M extractions using no lingual retractor, repurposed, and purpose-built retractors. No lingual retraction showed a 0.60% risk of temporary and a 0.08% risk of permanent injury to the nerve. Repurposed retractors showed a 7.9% risk of temporary and 0.41% risk of permanent injury, and purpose-built retractors a 0.56% risk of temporary injury. No reported cases of permanent injury were associated with the use of purpose-built instruments. The evidence suggests that whilst the use of repurposed retractors increases the risk of injury to the nerve, there is no such risk with purpose-built retractors. Current data sets are confounded by the limitations of non-randomised, non-blinded studies, but trends show that lingual nerve retraction with purpose-built retractors may help to prevent permanent injury to the lingual nerve.

The first pterosaur basihyal, shedding light on the evolution and function of pterosaur hyoid apparatuses

The pterosaur is the first known vertebrate clade to achieve powered flight. Its hyoid apparatus shows a simplification similar to that of birds, although samples of the apparatus are rare, limiting the ability to make an accurate determination. In this study we reveal a new pterosaur specimen, including the first definite basihyal. Through the comparison of pterosaur hyoids, a trend has been discovered for the shortened hyoid relative to the length of the skull, indicating a diminished role of lingual retraction during the evolution of the pterosaur. The new material, possibly from a gallodactylid Gladocephaloideus, represents one of the least effective lingual retractions in all pterosaurs. Based on the structure of an elongated ceratobranchial and retroarticular process on mandibles, the function of the Y-shaped istiodactylid tongue bone is similar to those of scavenger crows rather than chameleons, which is consistent with the interpretation of the scavenging behavior of this taxon. More fossil samples are needed for further study on the function of other pterosaur hyoids.

The Treatment of Lip Protrusion Which Demands Intrusion and Bodily Movement of Upper Anterior Tooth with Antero-Posterior Lingual Retractor Combined with Clear-Aligner

As the number of adult patients has been growing, many patients tend not to want to show their appliances to others during treatment. There are two major different types of esthetic orthodontic appliance for such patients. In spite of remarkable development of clear-aligner in terms of its material, structure and wearing protocol, the indication has not been expanded as widely as that of lingual appliance. In lingual technique, it is further more complex to apply each different biomechanics necessary to different symptoms than it is in labial mechanics. Although there has been numerous trials to treat extraction case with esthetic appliance, it can cover only few types of case for extraction treatment. As this case has protrusion with uprighted incisor and gummy smile, we applied antero-posterior lingual retractor (APLR) and clear-aligner combined treatment to carry out root movement and intrusion of upper anterior tooth. The treatment result confirms that this esthetic remedy could be applied to other extreme cases that demand root movement and vertical control in upper anteriors, which could not be improved solely with conventional esthetic appliances.

Should we do a lingual retraction similar to sagittal split osteotomy for all standard third molar surgery?

Should we do a lingual retraction similar to sagittal split osteotomy for all standard third molar surgery?

Coronectomy in Third Mandibular Molars as an Alternative Treatment to Prevent Damage to the Inferior Alveolar Nerve: Bibliographic Review and 30 Cases Report

The inferior alveolar nerve (IAN) injury to remove the third molars is often caused by the intimate relationship between the nerve and the roots of the teeth. Coronectomy technique or intentional root retention, may minimize this problem. Thirty patients underwent coronectomy in 30 third molars with follow up of at least 6 months. Coronectomy technique deliberately protected the lingual nerve as part of the surgical procedure. All roots were at least 3 mm below the buccal and lingual bony walls. All patients were radiographed preoperatively, immediately postoperatively, and after 6 months. There were no cases of IAN damage involved in this study of 30 patients who underwent 30 coronectomies. There was one case of transient lingual nerve involvement, probably by the use of lingual retractor. One patient required subsequent removal of the roots of both lower third molars, due to lack of healing, and one patient required subsequent removal of a root cause of migration back to the surface. migration of the roots was observed in approximately 30 % of patients during a period of six months. Coronectomy seems to be a viable technique in those cases where the removal of all tooth could put the IAN at considerable risk of damage. The technique appears to be associated with a low incidence of complications, but the subsequent migration of the roots can be a problem in the long term.

Control of anterior segment using an antero-posterior lingual sliding retraction system: a preliminary cone-beam CT study

BackgroundThis study was performed to evaluate the treatment effects of the antero-posterior lingual retractor (APLR), focusing on the 3-dimensional (3D) tooth movement of the maxillary anterior teeth and their alveolar bone levels.MethodsEn masse retraction was performed using either the C-lingual retractor (CLR, C-group, n = 9) or the antero-posterior lingual retractor (APLR, AP-group, n = 8). We evaluated 3D movement of the maxillary anterior teeth and alveolar bone levels, root length of the central incisors, long axes of the maxillary canines, and occlusal plane changes from CBCT images.ResultsAfter retraction, the central incisors were more significantly intruded and their root apex was more retracted in the AP-group. The long axis of the canine was well maintained in the AP-group. There were no differences in the steepness of occlusal plane and the incidence of alveolar bone loss or of root resorption during en masse retraction with the two retractors.ConclusionsThe clockwise bowing effect of the anterior segment was less with the APLR, which prevented unwanted canine movement.

Gummy Smile Correction Using Lingual Orthodontics and Augmented Corticotomy in Extremely Thin Alveolar Housing.

Tooth movement out of anatomic limitations was assisted by augmented corticotomy using deproteinized bovine bone mineral. Lip protrusion can be reduced by premolar extraction followed by retraction of the anterior teeth. Surgical intervention is appropriate when the alveolar bone housing of the anterior region is insufficient for the tooth movement. In this patient, corticotomy in upper palatal area and anterior segmented osteotomy in the mandible were performed. Anatomic limitation to the retraction was expanded by xenograft. An antero-posterior lingual appliance was used to bodily retract the upper anterior teeth. The gummy smile was resolved by intrusion of upper entire arch using 2 mid-palatal temporary skeletal anchorage devices. New bone formation was observed on palatal side of upper anterior teeth. The teeth were moved into augmented area without fenestration or vitality loss. Lip protrusion was resolved, and the gummy smile was effectively improved. Orthodontic tooth movement beyond the limitation of the alveolar bone housing can be achieved with surgical assistance, which can be performed under local anesthesia. Without orthognathic surgery, the gummy smile can be reduced using an antero-posterior lingual retractor with mid-palatal skeletal anchorage.

A Self-Retaining Lingual Flap Guarding Device During Surgical Removal of Impacted Mandibular Third Molar

Lingual nerve damage is one of the common complications following mandibular third molar surgery. On considering the impact of lingual nerve damage on the patient's quality of life, it is necessary to exercise caution to minimize its occurrence. Although many lingual retractors are available, in this article we describe an indigenously designed lingual retractor for use in mandibular third molar surgery. The indigenous lingual retractor described in this article provides advantages like clear access and excellent retention unlike conventional retractors.

Effects of labial and lingual retraction and intrusion force on maxillary central incisor with varying collum angles: A three-dimensional finite elemental analysis

Effects of labial and lingual retraction and intrusion force on maxillary central incisor with varying collum angles: A three-dimensional finite elemental analysis

Effects of labial and lingual retraction and intrusion force on maxillary central incisor with varying collum angles: A three-dimensional finite elemental analysis

Effects of labial and lingual retraction and intrusion force on maxillary central incisor with varying collum angles: A three-dimensional finite elemental analysis

Current practice in mandibular third molar surgery. A national survey of British Association of Oral Surgeons membership

AbstractObjectiveThe aim of this survey was to evaluate current practice in mandibular third molar (M3M) surgery within the British Association of Oral Surgeons (BAOS) membership against current evidence and relevant guidelines.MethodAn online questionnaire survey was active from March to June 2015.ResultsA total of 250 BAOS members (48%) responded to the survey. About 52% were registered Oral Surgery specialists. Exactly, 36% stated that M3M surgery comprised 50–75% and 17% stated that M3M surgery comprised over 75% of their workload. About 73% would recommend coronectomy for high‐risk M3Ms; however, 53% had difficulty in accessing cone beam CT (CBCT) scanning. Most practitioners undertook a two‐stage written consent informing patients of the possibility of numbness, altered sensation or pain as a result of inferior alveolar or lingual nerve injury; however, there were significant variations in how this was communicated. Most surgeons operated mainly under local anaesthesia, using a triangular buccal flap access; 27% routinely used lingual retraction. Buccal and distal bone removal followed by sectioning of the tooth was the most common approach, although 1% routinely used the lingual split technique. Over the last 5 years, each responder reported an average of 2 temporary and 0.4 permanent inferior alveolar nerve injuries (IANI), 1 temporary and 0.1 permanent lingual nerve injuries (LNI).ConclusionThis survey has highlighted the lack of access to CBCT scanning and the differences in approach to consent and surgical technique. The reported rates of nerve injury caused by M3M surgery were low; however, this may be due to a lack of post‐operative follow up.

Self-retaining retraction of the tongue

g t then placed over the retractor and under the arms of the mouth gag to hold the retractor in place (Figs. 1 and 2). The arms of etraction and protection of the tongue when operating in he oral cavity, and particularly around the mandible, can be ifficult. It is normally done by the assistant, but it occupies heir attention and limits them to having only one hand free o assist the operator. We have used 3 instruments commonly ound in operating theatres to provide mouth opening and elf-retaining retraction of the tongue. The 3 components are long, serrated Gillie’s dissecting orceps, a Featherstone mouth gag, and a right-angled tongue etractor (we used a Whitlock lingual retractor). The mouth