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At least 811 records · Page 45Linked to original sources
PubMed1992

Secondary retention of permanent molars: an assessment of ankylosis by scanning electron and light microscopy.

Secondary retention refers to the cessation of eruption of a tooth after emergence. This may be the result of pathological changes in the periodontal ligament. The aim of this study was to describe the morphological and histological aspects of the radicular surface of secondarily retained permanent molars. The roots of 12 secondarily retained molars and two control molars, were examined by means of scanning electron microscopy (SEM) and light microscopy (LM) in order to analyse the occurrence and localisation of ankylosis. With SEM it was observed that the root surface of retained molars showed local areas covered with bonelike tissue. LM of these areas showed that this tissue was bone in direct contact with the root surface (ankylosis). In 11 cases, the areas of ankylosis were observed in the bifurcation area and at the interradicular root surface. In the remaining case, ankylosis was located at the outer root surface. The results of this study endorse the assumption that focal ankylosis is an important factor in secondary retention. Treatment recommendations must be based on this fundamental principle, because orthodontic movement of ankylotic molars is not possible.

Adolescent↗
PubMed1995

Third molar surgery: an audit of the indications for surgery, post-operative complaints and patient satisfaction.

A prospective investigation was undertaken of 522 patients undergoing third molar surgery. Data relating to indications for surgery and quality of care were collected on both pre- and post-operative proformas. This investigation showed that over half of the patients did not have clinically sound indications for surgery. The incidence of post-operative complications was approximately the same as other studies on third molar surgery. Patient satisfaction was at a high level, although this study revealed that a percentage of symptom-free patients undergoing third molar surgery sustained nerve damage some of which remains unreported. Clear and well defined indications for third molar surgery do exist and should be adhered to. Operating on patients without good reason involves unnecessary expenditure to purchasing authorities, cost to the patient in both time off work and post-operative complications and further, may result in potentially avoidable legal problems for practitioners. A reappraisal of the impacted third molar is indicated prior to committing the patient to surgery, such that the indications for surgery are compatible with current views on quality assurance, health service economics and medico-legal common sense.

Cost of Illness↗
PubMed1983

Periodontal evaluation of two mucoperiosteal flaps used in removing impacted mandibular third molars.

This study compared the results of two types of access flap used in removing impacted mandibular third molars. Fifteen patients were given periodontal examinations consisting of measurements of attachment level, level of the gingival margin, and width of the masticatory mucosa at three locations around the mandibular second molars. The examinations were done preoperatively, and two, six, and 12 weeks after removal of the impacted molars. Analyses of variance indicated that there was no significant difference between the two flap techniques and, therefore, the choice of flap technique is one of operator preference. There was a significant decrease in mean sulcus depth at all measured points for either flap technique, indicating a generally healthier condition around mandibular second molars 12 weeks after the surgical removal of mandibular third molars.

Adult↗
PubMed1984

Clinical and anatomic observations on the relationship of the lingual nerve to the mandibular third molar region.

The position of the lingual nerve in the mandibular third molar region was measured and photographed in 34 cadaver dissections and 256 cases of third molar extraction. In 17.6% of the dissections the lingual nerve was found at the level of the alveolar crest or higher. Horizontally the nerve contacted the lingual plate of the third molar in 62% of the specimens. Of 256 patients, the nerve was visualized above the height of the lingual plate of the lower third molar in 12 (4.6%). These results document the vulnerability of the lingual nerve as it passes medially to the mandibular third molar.

Adult↗
PubMed1987

Prospective study of dysesthesia following odontectomy of impacted mandibular third molars.

Dysesthesia following odontectomy of impacted mandibular third molars is observed in some patients. This prospective study reports the clinical incidence of this untoward sequela to occur in 3.3% of patients. An analysis of possible etiologic factors reveals that development of dysesthesia of the inferior alveolar and lingual nerves is more likely to occur with: complete bony impacted mandibular third molars; mesioangular impacted third molars; impacted third molars with the crown at the cemento-enamel junction of the second molar; and when burs are used to remove bone and when the roots approximate the inferior alveolar canal.

Adolescent↗
PubMed1987

An evaluation of combination second molar extraction and functional appliance therapy.

The purpose of this study was to examine the results of a treatment regimen involving the extraction of four second molars followed by a combination of sagittal, Bionator, and fixed appliance therapy. The pretreatment and posttreatment cephalometric and dental cast records of 30 consecutively treated Class II, Division 1 cases were evaluated. Results showed that the Class II skeletal correction was achieved by a "headgear" effect inhibiting maxillary growth in conjunction with normal forward mandibular growth. No significant distal bodily movement or tipping of either maxillary or mandibular first molars was found. Significant increases were seen in maxillary arch length, maxillary intercanine and intermolar width, and mandibular intermolar width as a result of treatment. Maxillary third molar position tended to improve following second molar extraction; mandibular third molar changes were more variable.

Activator Appliances↗
PubMed2006

Comparison of second molar eruption patterns in patients with skeletal Class II and skeletal Class I malocclusions.

INTRODUCTION: The eruptive positions of the second molars in Class I and Class II malocclusions were studied. METHODS: Pretreatment records of 221 patients with a mean age of 11.3 years were evaluated. About 19% of them had skeletal Class I, 31% had skeletal maxillary Class II, and 50% had skeletal mandibular Class II malocclusions. RESULTS: The mean values of the dental and chronologic ages of the subjects were similar. The eruptive positions in relation to a reference line, the developmental stages of the patients' second molars and dental ages were recorded from the panoramic roentgenograms. The distribution of the various developmental stages in each malocclusion group was similar, and no association between skeletal malocclusion and dental developmental stage of the second molars was encountered. The eruptive position of the maxillary second molars was more occlusal only in the oldest maxillary Class II group, above 12 years of age (P = .02). CONCLUSIONS: These results support, in part, previous reports suggesting that the maxillary second molars may erupt earlier in patients with skeletal maxillary Class II malocclusions.

Analysis of Variance↗
PubMed2007

Osseointegrated implants with pendulum springs for maxillary molar distalization: a cephalometric study.

INTRODUCTION: Maxillary molar distalization is a common treatment approach for patients with Class II malocclusions who do not require extractions. Despite the many advantages of pendulum appliances, the maxillary incisors and premolars tend to shift mesially as the maxillary molars move distally. The purpose of this study was to investigate anchorage loss in patients treated with palatal osseointegrated implants combined with pendulum springs. METHODS: Pretreatment and posttreatment lateral cephalometric films of 30 consecutively treated patients were examined. One group (n = 15) had been treated with conventional pendulum appliances, and the other group (n = 15) was treated with palatal osseointegrated implants combined with pendulum springs. RESULTS: In the pendulum group, significant distal tipping of the maxillary first molars and mesial tipping of the maxillary premolars were noted. Distalization of the maxillary first molars, mesialization of the maxillary first premolars, and proclination of the maxillary left central incisor were significant in the linear measurements. In the implant group, the distal tipping of the maxillary first molars and first premolars and the increases in SNGoGn, FMA, Na Me, and Na ANS were significant. Intergroup comparisons showed that changes in the maxillary first premolars, maxillary central incisors, and vertical measurements were significant. CONCLUSIONS: The use of palatal osseointegrated implants is reliable and provides absolute anchorage.

Cephalometry↗
PubMed2006

True molar intrusion attained during orthodontic treatment: a systematic review.

INTRODUCTION: The aim of this systematic review was to quantify the amount of true molar intrusion attainable during orthodontic treatment. METHODS: A literature search was conducted to identify clinical trials that assessed true molar intrusion through superimposition of lateral cephalogram tracings. Craniofacial growth had to be factored out when appropriate. Electronic databases (Pubmed, Medline, Medline In-Process & Other Non-Indexed Citations, all EBM reviews, Embase, Web of Science, and Lilacs) were searched with the help of a senior health-sciences librarian. Abstracts that appeared to fulfill the initial selection criteria were selected, and the full-text original articles were then retrieved and analyzed. Only articles that fulfilled the final selection criteria were finally considered. Their references were also hand-searched for possible missing articles from the database searches. RESULTS: Thirty abstracts met the initial inclusion criteria, and these articles were retrieved. From these, 29 were later rejected because they did not either quantify true molar intrusion or factor out normal craniofacial growth when required. Only 1 article remained, and it showed a mean maxillary molar intrusion of 0.96 mm (SD, 0.54) in 12 subjects. CONCLUSIONS: True molar intrusion appears to be achievable in the maxillary arch, although the amount of evidence is minimal. The clinical significance of the magnitude of the true intrusion reported is questionable as the sole treatment option to correct open-bite malocclusions. Better quantification method of the true intrusion attained has to be utilized.

Clinical Trials as Topic↗
PubMed2006

Comparison and measurement of the amount of anchorage loss of the molars with and without the use of implant anchorage during canine retraction.

INTRODUCTION: The purpose of this study was to compare and measure the amount of anchorage loss with titanium microimplants and conventional molar anchorage during canine retraction. METHODS: Subjects for this study comprised 10 orthodontic patients (7 women, 3 men) with a mean age of 19.6 years (range, 18 to 25 years), who had therapeutic extraction of all first premolars. After leveling and aligning, titanium microimplants 1.3 mm in diameter and 9 mm in length were placed between the roots of the second premolars and the first molars. Implants were placed in the maxillary and mandibular arches on 1 side in 8 patients and in the maxilla only in 2 patients. A brass wire guide and an intraoral periapical radiograph were used to determine the implant positions. After 15 days, the implants and the molars were loaded with closed-coil springs for canine retraction. Lateral cephalograms were taken before and after retraction, and the tracings were superimposed to assess anchorage loss. The amount of molar anchorage loss was measured from pterygoid vertical in the maxilla and sella-nasion perpendicular in the mandible. RESULTS: Mean anchorage losses were 1.60 mm in the maxilla and 1.70 mm in the mandible on the molar anchorage side; no anchorage loss occurred on the implant side. CONCLUSIONS: Titanium microimplants can function as simple and efficient anchors for canine retraction when maximum anchorage is desired.

Adolescent↗
PubMed2005

Removal of third molars in Scottish oral and maxillofacial surgery units: a review of practice in 1995 and 2002.

We audited the practice of removal of third molars in Scottish oral and maxillofacial (OMFS) units in 1995 and in 2002. We collected data from anonymous structured postal questionnaires from 12 Scottish OMFS units about patients referred for removal of third molars in 1995 and 11 units in 2002. The percentage of patients who had no treatment increased from 11% in 1995 (102/928) to 16% in 2002 (66/412). The incidence of prophylactic removal of third molars decreased between the two periods. Removal of third molars under local anaesthesia with or without sedation increased from 35% (325/928) in 1995 to 54% (223/412) in 2002. Removal of third molars under general anaesthesia decreased from 54% in 1995 to 30% in 2002.

Anesthesia, Dental↗
PubMed2005

Variation in hominoid molar enamel thickness.

Enamel thickness has figured prominently in discussions of hominid origins for nearly a century, although little is known about its intra-taxon variation. It has been suggested that enamel thickness increases from first to third molars, perhaps due to varying functional demands or developmental constraints, but this has not been tested with appropriate statistical methods. We quantified enamel cap area (c), dentine area (b), and enamel-dentine junction length (e) in coronal planes of sections through the mesial and distal cusps in 57 permanent molars of Pan and 59 of Pongo, and calculated average (c/e) and relative enamel thickness (([c/e]/ radicalb) * 100). Posteriorly increasing or decreasing trends in each variable and average (AET) and relative enamel thickness (RET) were tested among molars in the same row. Differences between maxillary and mandibular analogues and between mesial and distal sections of the same tooth were also examined. In mesial sections of both genera, enamel cap area significantly increased posteriorly, except in Pan maxillary sections. In distal sections of maxillary teeth, trends of decreasing dentine area were significant in both taxa, possibly due to hypocone reduction. Significant increases in AET and RET posteriorly were found in all comparisons, except for AET in Pongo distal maxillary sections. Several significant differences were found between maxillary and mandibular analogues in both taxa. Relative to their mesial counterparts, distal sections showed increased enamel cap area and/or decreased dentine area, and thus increased AET and RET. This study indicates that when AET and RET are calculated from samples of mixed molars, variability is exaggerated due to the lumping of tooth types. To maximize taxonomic discrimination using enamel thickness, tooth type and section plane should be taken into account. Nonetheless, previous findings that African apes have relatively thinner enamel than Pongo is supported for certain molar positions.

Animals↗
PubMed2006

Anatomical study of C-shaped canals in mandibular second molars by analysis of computed tomography.

The aim of this study was to investigate the prevalence and configuration of the C-shaped canal using serial axial computed tomography images of the mandibular second molars that had not been restored severely or treated endodontically, and to compare the thickness of the remaining tooth structure from the center of the canal to the outer surface of the deepest groove area in C-shaped mandibular second molar to that of "danger zone of perforation" in normal mandibular second molar. This distance was measured at the cervical, middle, and apical third level each. From 220 teeth, C-shaped canals were found in 98 teeth (44.5%). Almost all the grooves were directed lingual (99%). The continuous C-shaped canal was the most frequently found (49%) and the separated canal was the least (17.4%). The thinnest remaining tooth structure in the groove area of the C-shaped mandibular second molar was not different from that of the danger zone of normal mandibular second molar at the three levels (p > 0.05).

Adolescent↗
PubMed2003

Risk factors associated with prolonged recovery and delayed healing after third molar surgery.

PURPOSE: We sought to identify the demographic, oral health, and surgical risk factors associated with prolonged recovery after third molar surgery using health-related quality of life (HRQOL) and clinical outcomes. PATIENTS AND METHODS: HRQOL responses from patients and clinical outcomes were obtained after third molar surgery. Criteria were selected for HRQOL outcomes that separated patients with from those without prolonged recovery. Delayed clinical healing was indicated by a patient having at least 1 postsurgery visit with treatment. Risk assessment models for prolonged HRQOL recovery and delayed clinical healing were developed using stepwise logistic regression analysis. RESULTS: We included 547 subjects with HRQOL and clinical outcome data in this analysis. Age, gender, and occlusal plane position were statistically significantly associated with prolonged recovery for early symptoms, oral function, and pain. Recovery for lifestyle was prolonged only if both lower third molars were below the occlusal plane before surgery. Age, gender, prior symptoms related to the third molars, and the surgeon's perception of difficulty were statistically significant predictors of delayed clinical recovery. CONCLUSIONS: Certain demographic and oral health conditions available to the surgeon before surgery, and characteristics of the surgery itself, increase the risk of a prolonged recovery for HRQOL outcomes and delayed clinical outcomes after third molar surgery.

Adolescent↗
PubMed2004

Lingual flap retraction for third molar removal.

PURPOSE: Lingual nerve damage following lower third molar surgery remains a clinical problem. The traditional approach in the United States has been a buccal approach avoiding exposure or surgery on the lingual side of the crest of the ridge. An alternative technique is to deliberately expose the lingual tissues and retract the lingual nerve lingually before tooth removal. This study reports a trial of this technique. MATERIALS AND METHODS: Patients had removal of their lower third molars carried out using a technique that raises a lingual flap in addition to a buccal flap and places a specially designed lingual retractor to ensure that the lingual nerve is held out of the surgical field. This technique was used in cases where the crown of the tooth had to be sectioned or when distal bone needed to be removed. RESULTS: Two hundred fifty patients were treated by this method. There were 4 cases of transient lingual paresthesia, presumably caused by traction pressure from the retractor. Three of these cases were mild and resolved within 3 weeks. The fourth case had more profound paresthesia, but still resolved within 2 months. There were no cases of permanent nerve damage, and in many cases removal of the third molar was simplified by the superior access. CONCLUSION: Lingual retraction for third molar removal improves access to the surgical site and can simplify third molar removal. In this prospective study there were no cases of permanent lingual nerve injury.

Alveolectomy↗
PubMed2005

Frequency of trigeminal nerve injuries following third molar removal.

PURPOSE: To estimate oral and maxillofacial surgery reporting of the frequency of temporary and permanent inferior alveolar and lingual nerve damage from lower third molar extraction and injury etiology, and to identify factors associated with injury rates. MATERIALS AND METHODS: A postal survey was sent to all members of the California Association of Oral and Maxillofacial Surgeons requesting information on known instances of inferior alveolar and lingual nerve damage that had occurred in their practices over a 12-month period and known instances of permanent damage over their entire careers. RESULTS: Replies were obtained from 535 California Oral and Maxillofacial Surgeons (OMFS) representing 86% of all OMFS in California. Instances of injury to the inferior alveolar nerve in a 12-month period were reported by 94.5% of OMFS; 53% reported instances of lingual nerve injury in a 12-month period. Instances of permanent nerve injury of the inferior alveolar nerve were reported by 78% of OMFS; 46% reported permanent lingual nerve injury occurring during their professional lifetime. The overall estimated self-reported rate of injury was 4 per 1,000 lower third molar extractions for the inferior alveolar nerve and 1 per 1,000 extractions for the lingual nerve for all cases (temporary and permanent). In most cases (80%) of inferior alveolar nerve injury the cause was known, but in a majority of cases of lingual nerve injury (57%) the injury etiology was unknown. Self-reported rates of permanent injury were 1 per 2,500 lower third molar extractions for the inferior alveolar nerve and 1 per 10,000 lower third molar extractions for the lingual nerve. Injury rates were associated with provider experience (ie, extractions per year) and years in practice. CONCLUSION: This survey included a high percentage of California OMFS. Injury to the inferior alveolar and lingual nerve was reported by most OMFS in California following lower third molar removal, and many reported cases of permanent nerve injury, frequently with unknown cause.

California↗
PubMed2006

A 10-year comparative study of the incidence of third molar removal in the aging population.

PURPOSE: The study goal was to evaluate the incidence of patients older than 40 years who required third molar removal. PATIENTS AND METHODS: Two prospective 5-year studies were compared over a 10-year period of 1992 to 1997 and 1997 to 2002. The study was initiated to evaluate how the large increase in the older population with longer life expectancies is reflected in the third molar population. RESULTS: In 1997, 10.5% of patients requiring third molar surgery were 40 years or older. In 2002, 17.3% of patients were 40 years or older. CONCLUSIONS: It is well known that patients 40 years and older have increased risk in removal of third molars. It is concluded that 1 patient in 5 in the high-risk category is in a very high risk category. The risk to patients and to the profession can be dramatically reduced by considering early removal of abnormal third molars.

Adult↗
PubMed2005

Long-term survival of endodontically treated molars without crown coverage: a retrospective cohort study.

STATEMENT OF PROBLEM: Teeth are weakened after endodontic treatment and should, ideally, be crowned, especially posterior teeth. However, this is not always possible. Information about the longevity of endodontically treated teeth without crown coverage may assist in selecting appropriate treatment modalities. PURPOSE: The aims of this cohort study were to evaluate the survival rate for endodontically treated molars without crown coverage and to identify possible related factors. MATERIAL AND METHODS: A total of 220 endodontically treated permanent molar teeth in 203 subjects on a waiting list for fixed prosthodontic treatment at the Faculty of Dentistry-Mahidol University, Thailand, were included. Follow-up data were derived from a clinical examination and review of the dental record and radiographs. Subjects were not included in the study if teeth had provisional crowns, definitive restorations with cuspal coverage, or with dowel and core and/or crown restorations. The outcome evaluated was defined as a failure if there were negative findings in the condition of a tooth that required a restoration, tooth repair, or extraction. Tooth loss due to endodontic and periodontal reasons was excluded. The independent variables assessed were patient age, gender, location (maxilla or mandible), the existence of an opposing dentition and adjacent teeth, remaining tooth structure, and types of restorative material. Kaplan-Meier analysis with a 95% confidence level was used to calculate the survival probability, and a log-rank test was used to determine whether significant differences existed. RESULTS: Overall survival rates of endodontically treated molars without crowns at 1, 2, and 5 years were 96%, 88%, and 36%, respectively. With greater amounts of coronal tooth structure remaining, the survival probability increased. Molar teeth with maximum tooth structure remaining after endodontic treatment had a survival rate of 78% at 5 years. Restorations with direct composite had a better survival rate than conventional amalgam and reinforced zinc oxide and eugenol with polymethacrylate restorations. CONCLUSION: Within the limitations of this study, the amount of remaining tooth structure and types of restorative material have significant association with the longevity of endodontically treated molars without crown coverage.

Acrylic Resins↗