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A comparison of morbidity following the removal of lower third molars by the lingual split and surgical bur methods.

Fifty-two consecutive healthy patients with bilateral, similarly impacted mandibular third molars were studied. For each patient, both third molars were removed at the same operation by the same experienced operator. On one side, the lingual split method by chisel was used; on the other, the buccal approach with surgical bur. Standard preoperative and postoperative drug regimens were used. Pain, facial swelling (visual analogue scales), and lingual and labial sensory disturbance were recorded for each side by the patients at home 6, 24, and 48 h and 7 days after surgery. Wound healing was assessed at 4 weeks. There were no statistically significant differences between methods in relation to pain, facial swelling, sensory loss, infection, or periodontal pocket depth distal to the second molar, although 2% of third molars removed by chisel had lingual sensory disturbance at 7 days, as compared with 8% where burs had been used. There were no statistically significant differences between duration of procedures; mean operating time with burs was 8.28 min (range 4-15 min) and with chisels 7.57 min (range 4-15 min). This study provided no evidence of difference in either efficiency or outcome between two standard methods of removing lower third molars.

Adolescent↗

Infections in elderly patients associated with impacted third molars.

The objective of this study was to determine the clinical characteristics of infections caused by impacted third molars in elderly persons. Infectious disorders (26 pericoronitis, 8 secondarily infected dentigerous cysts, 4 perimandibular abscesses with limited osteomyelitis, 2 chronic mandibular osteomyelitis, and 1 odontogenic skin fistula) associated with the impacted third molars impacted third molars were clinically investigated in 41 patients over 60 years of age. Twenty-nine causative teeth were located in the mandibular angle and nine in the ramus; the three remaining lesions (two cysts one pericoronitis) were associated with the maxillary third molar. Bone resorption was noted in most patients, and this caused the originally embedded tooth to become exposed intraorally. It was concluded that oral infection in elder persons are occasionally caused by retained impacted third molars with overlapping of other factors.

Age Factors↗

Gustatory function after third molar extraction.

OBJECTIVE: The purpose of this study was to determine the severity and time course of taste changes after extraction of all 4 third molars. STUDY DESIGN: Taste function in 17 patients was measured before third molar surgery and at 1 month and 6 months after surgery. Two tests were administered: a whole-mouth, above-threshold test in which subjects sipped, expectorated, and then rated the intensities and identified the taste qualities of various solutions, and a localized test in which subjects rated and identified solutions painted with cotton swabs on different oral sites. RESULTS: Intensity ratings for solutions in the whole-mouth test were reduced by approximately 14% for NaCl, citric acid, and quinine hydrochloride at 1 month after surgery and had not recovered by 6 months after surgery for citric acid (P<.02). The taste quality of NaCl was identified correctly less frequently after third molar extraction. Perceived taste intensity on discrete areas of the tongue was significantly reduced after surgery (P<.05). Patients with the most severely impacted molars gave the lowest taste intensity ratings to whole-mouth test solutions at 6 months after surgery (P<.02). In contrast, taste function in a group of subjects who received only local dental anesthesia was not affected. CONCLUSIONS: Gustatory deficits occur after third molar extraction, persist for as long as 6 months after surgery, and appear to be associated with depth of impaction.

Adolescent↗

Time and duration of eruption of first and second permanent molars: a longitudinal investigation.

OBJECTIVE: The aim of this study was to investigate the variation in (i) the time (age) of eruption and (ii) the duration of the eruption of first (M1) and second (M2) permanent molar teeth. Finally, the study also provides data about the association between time of eruption of the first of the M1s and the first of the M2s. METHODS: The study was carried out in Nexö Public Dental Health Service, Denmark. All children who, in a period of 12 months, had the first of their M1s or M2s recorded as erupted and the occlusal surface still partly covered by gingiva formed the study groups (N = 69 and 112 children, respectively). The continued eruption of all four molar teeth was recorded at recall intervals not exceeding 4 months until functional occlusion was obtained. RESULTS: First permanent molars: eruption time--girls: from the age of 5 years and 3 months to 7 years and 8 months (mean 6.1 years); boys: from 5 years and 2 months to 7 years and 10 months (mean 6.3 years). The duration of eruption--girls: from 5 to 32 months (mean 15.4 months); boys: from 7 to 28 months (mean 15.0). Second permanent molars: eruption time--girls: from the age of 8 years and 11 months to 14 years and 4 months (mean 11.3 years); boys: from 9 years and 11 months to 13 years and 11 months (mean 12.0 years). The duration of eruption--girls: from 12 to 44 months (mean 27.1 months); boys: from 9 to 45 months (mean 27.9 months). No correlation was found between the time of eruption and the duration of eruption of M1 or M2. There was a strong positive association between the time of eruption of the M1s and the M2s (r(s) = 0.81). CONCLUSIONS: A tremendous variation was found in time of eruption and in duration of eruption of permanent molars. This variation highlights the importance of individualizing caries preventive strategies for children.

Age Factors↗

Effects of glass ionomer sealants in newly erupted first molars after 5 years: a pilot study.

OBJECTIVES: The aim of the study was to investigate the caries-preventive effect of high-filled glass ionomer sealant in newly erupted first molars in a high-risk group. This investigation is part of a larger study amongst eight hundred and thirty-five 6-7-year-old Syrian children. METHODS: Children that had 1, 2 or 3 just erupted or erupting and at least one unerupted first molar (control) were enrolled in this pilot study. A total of 60 children fulfilled the inclusion criteria. There were 49 children with a total of 83 sealants available for examination at the evaluation year 5. RESULTS: Almost two out of the three sealants (69%) had disappeared between evaluation years 2 and 3. 1.2% (SE = 1.2) of the sealants survived were fully retained and 10.3% (SE = 3.3) of the sealants survived were fully and partially retained at the evaluation year 5. Caries prevalence of the children in the study group at the evaluation year 5 was 55%. The Odds ratio concerning sealed and control group at year 5 was 2.6 with 95% confidence limits of 1.2 and 5.7, implying a relative risk (RR) of 2.1. Unsealed unerupted first molars had 2.1 times higher chance than sealed newly erupted first molars to develop dentinal lesions in this child population after 5 years. CONCLUSIONS: It is concluded that sealing newly erupted first molars with high-filled glass ionomer may be a caries-preventive measure in high-risk children. However, a well-designed clinical trial should be implemented to confirm the initial findings.

Adolescent↗

A comparison of enamelin and amelogenin expression in developing mouse molars.

Amelogenin and enamelin are structural proteins in the enamel matrix of developing teeth. The temporal and spatial patterns of enamelin expression in developing mouse molars have not been characterized, while controversy remains with respect to amelogenin expression by odontoblasts and cementoblasts. Here we report the results of in situ hybridization analyses of amelogenin and enamelin expression in mouse molars from postnatal days 1, 2, 3, 7, 9, 14, and 21. Amelogenin and enamelin mRNA in maxillary first molars was first observed in pre-ameloblasts on the cusp slopes at day 2. The onsets of amelogenin and enamelin expression were approximately synchronous with the initial accumulation of predentin matrix. Both proteins were expressed by ameloblasts throughout the secretory, transition, and early maturation stages. Enamelin expression terminated in maturation stage ameloblasts on day 9, while amelogenin expression is still detected in maturation stage ameloblasts on day 14. No amelogenin expression was observed in day 21 mouse molars. Amelogenin and enamelin RNA messages were restricted to ameloblasts. No expression was observed in pulp, bone, or along the developing root. We conclude that amelogenin and enamelin are enamel-specific and do not directly participate in the formation of dentin or cementum in developing mouse molars.

Ameloblasts↗

Different distribution of immunocompetent cells in the dentogingival junction during root formation in rat molars.

The distribution of immunocompetent cells in the dentogingival junction of rat molars during root formation was investigated by immunocytochemistry using antibodies to class II major histocompatibility complex (MHC) molecules (OX6-antibody) and monocyte/macrophage lineage cells (ED1-antibody) as well as by histochemical reaction for periodic acid-Schiff (PAS). Two portions (the junctional epithelium in the mesial gingiva of the first molar, and the interdental gingiva between the first and second molars) were selected for observations. At the eruption stage of the first molar (16-18 days after birth), OX6-positive cells, dendritic or oval in shape, were abundantly distributed in the connective tissue between the oral epithelium and tooth germ. Positive cells with slender cell processes were also found beneath the ameloblast layer. At the commencement stage of the first molar occlusion (24-28 days after birth), numerous OX6-positive cells displaying a dendritic fashion existed preferentially in the mesial gingiva, but were fewer in the interdental gingiva. In contrast, the interdental gingiva showed a denser distribution of ED1-positive cells and PAS-reactive polymorphonuclear leukocytes (PMLs) than the mesial gingiva. At the completion stage of root formation (100-120 days after birth), the OX6-immunopositive cells invaded the deeper position of the mesial gingiva with the downgrowth of the epithelium; they had a considerably higher cell density compared with those in the interdental gingiva where PAS-reactive PMLs persisted. These findings indicated that the immunocompetent cells showed a region-specific distribution and cell density by their roles in immune response.

Ameloblasts↗

Perceived risk of future pathology associated with pathology-free third molars: a comparison of oral and maxillofacial surgeons and family dentists.

OBJECTIVE: To examine and compare practitioners' judgements of risk of future pathology associated with pathology-free disease asymptomatic third molars. SUBJECTS: 10 oral and maxillofacial surgeons and 18 family dentists (90% male) with experience ranging from 5-28 years. METHOD: Participants were presented with periapical radiographs of 36 asymptomatic, disease-free mandibular third molars and were informed of the age and sex of the patients and the degree of eruption of the third molars. Participants were asked to assess likelihood of future pathology in general, and more specifically, likelihood of root resorption, pericoronitis, periodontitis, cystic change and neoplasia if the third molar was left in situ. RESULTS: There was significant variation between the 28 raters but not between the two groups. Excepting assessment of future cystic change, there was no evidence that oral and maxillofacial surgeons and family dentists rated the 36 cases in consistently different ways. CONCLUSIONS: Practitioners varied very considerably in their judgment of the risks of pathology associated with asymptomatic disease-free third molars. Specialisation, did not account for this variation.

Adult↗

Comparison of decisions regarding prophylactic removal of mandibular third molars in Sweden and Wales.

OBJECTIVE: To test the hypothesis that Swedish dentists schedule more mandibular third molars for prophylactic removal compared with UK dentists and oral surgeons. DESIGN: Clinical and radiographic information relating to a stratified sample of 36 disease-free mandibular third molars (equal distribution of males and females, patients' age, angular position and degree of impaction) was presented to 26 general dental practitioners (GDPs) and 10 oral surgeons in Sweden and 18 GDPs and 10 oral surgeons in Wales who were asked to decide whether or not the third molars should be removed. RESULTS: There was no evidence of any difference in mean number of molars scheduled for removal by the GDPs, but the Swedish oral surgeons scheduled significantly more third molars for removal than oral surgeons in Wales. CONCLUSION: The less interventionist approach among oral surgeons in the UK may reflect the development and application of authoritative guidelines in the UK and an extensive debate concerning appropriateness of prophylactic removal there.

Adult↗

The fate and survival of amalgam and preformed crown molar restorations placed in a specialist paediatric dental practice.

The fate of 1688 amalgam restorations and 716 preformed crowns placed in permanent and primary molars in a specialist paediatric dental practice over a 10-year period by one operator is reported. For primary molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were, for Class 1 restorations, 16.1%, 3.9%, 73.3%, respectively, with an estimated median survival time greater than 8.5 years, and for Class 2 cavities 14.7%, 11.6%, 66.6%, with an estimated median survival time greater than 7.5 years. For permanent molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were for Class 1 restorations 11.5%, 6.5%, 76.8%, respectively, with an estimated median survival time greater than 9.3 years, and for Class 2 restorations 9.8%, 8.0%, 82.2%, with a median survival time greater than 8.5 years. For all preformed crowns, the replacement rate, true failure rate and 5-year survival estimates were 2.8%, 1.9%, 92.0%, and the estimated median survival time greater than 7.64 years. No relationship was observed between the age of the patient and the age of replaced restorations. No significant difference was found between the survival rates of Class 1 and 2 amalgam restorations in primary or permanent molars, nor between first and second primary molars.

Adolescent↗

Lower third molar treatment planning ability of general dental practitioners and oral maxillofacial surgeons using receiver operating characteristics methodology.

A comparison of lower third molar treatment planning ability of six oral and maxillofacial surgeons (three consultants, two senior registrars and one senior house officer) and 27 general dental practitioners was carried out using Receiver Operating Characteristics (ROC) methodology. Each clinician was presented with the same series of 50 case histories and asked to indicate, using a rating scale, how certain they were that each lower third molar required removal. These data, together with NIH gold standard treatment decisions for each third molar, were then used to construct ROC curves for each clinician and, using combined data, to produce ROC curves for the groups of hospital specialists and general dental practitioners. These curves were then compared statistically. There were significant differences between the best and worst practitioners, both in the hospital service and within general dental practice. When combined data were examined, however, there was no statistical difference in the treatment planning ability of hospital specialists and general dental practitioners. These findings indicate that lower third molar treatment planning ability is more dependent upon individual factors than specialist training. Further, the data presented here suggest that general dental practitioners are as capable of treatment planning for lower third molars as the specialists to whom they refer.

Clinical Competence↗

Late third molar genesis: its significance in orthodontic treatment.

(1) Third molar genesis may occur up to the age of sixteen years, although the possibility of their appearance after the age of twelve years is reduced. (2) When third molar genesis is delayed beyond the age of ten years, the possibility of all four third molars developing is reduced by about fifty percent. (3) The intraindividual variability in stage of development of third molars increase when genesis is delayed beyond ten years of age. (4) There is no significant difference in size of early and late developing third molars.

Adolescent↗

Ectopic eruption of the first permanent molars: prevalence and etiologic factors.

The purpose of this research was to study the prevalence of ectopic eruption of the first permanent molars and possible etiologic factors. A group of 4,232 Thai students, from 6 to 9 years old, was examined. The prevalence of ectopic eruption of the first permanent molars in the subjects was 0.75%. Both the severity of the ectopic eruption and the amount of root resorption on the second primary molars were more pronounced in the maxilla than in the mandible. The important etiologic factors were the eruption path of the first permanent molars relative to reference lines and the size of the mandibular second primary molars. The amount of proximal caries did not seem to affect the prevalence of ectopic eruption.

Analysis of Variance↗

The influences of molar intrusion on the inferior alveolar neurovascular bundle and root using the skeletal anchorage system in dogs.

The skeletal anchorage system (SAS) was developed as intraoral rigid anchors for open-bite correction by intrusion of molars. Since the application of SAS is a new modality in orthodontic treatment, the influences of radical molar intrusion on the root and the inferior alveolar neurovascular bundle were unknown. The purpose of this research is to verify the effect of molar intrusion on the neurovascular bundle, the level of osseointegration of bone screws, and root resorption. The results of this study showed mandibular molars were intruded 3.4 mm on the average over 7 months in dogs. The miniplates were well stabilized with osseointegrated bone screws and the peri-implant soft tissues showed slight inflammatory changes. Neither nerves nor blood vessels were damaged. Root resorption was observed but was repaired with new cementum. We concluded that the SAS utilizing transmucosal titanium miniplates as an immovable orthodontic anchorage could provide a new modality for molar intrusions without serious iatrogenic problems.

Alveolar Process↗

Bonded molar tubes--an in vitro evaluation.

This study aimed to evaluate the mean shear bond strength of molar tubes with micro-etched bases bonded with either a compomer (Ultra Band-Lok), a resin-modified glass ionomer cement (3M Multi-Cure or Fuji Ortho LC), or a light-cured resin adhesive (Transbond). The amount of adhesive remaining on the tooth surface following tube removal was assessed also. Finally, survival time of molar tubes bonded with each bonding agent was assessed following simulated mechanical fatigue in a ball mill. A total of 120 extracted human third molars were collected and randomly divided into 4 test groups. Thirty teeth (20 to assess debonding force and 10 to assess survival time) were bonded with each adhesive according to the manufacturers' instructions. Debonding was carried out using a Nene M3000 testing machine with a crosshead speed of 0.5 mm/min. The mean shear bond strength of tubes bonded with Transbond was significantly less than that of those bonded with 3M Multi-Cure (P = .0036) or Fuji Ortho LC (P < .0001). Tubes bonded with Ultra Band-Lok also had significantly lower mean shear bond strength than those bonded with Fuji Ortho LC (P = .020). Distribution of adhesive remnant index scores only differed significantly between tubes bonded with 3M Multi-Cure or Transbond. Only I molar tube, bonded with Transbond, debonded in the ball mill at 5 hours, but at 50 hours there was no significant difference in the survival time of tubes bonded with any of the bonding agents. Compomer or resin-modified glass ionomer cements appear to be viable alternatives to light-cured resin adhesive for bonding molar tubes.

Acrylic Resins↗

Bodily distalization of molars with absolute anchorage.

Palatal implants have been used over the last two decades to eliminate headgear wear and to establish stationary anchorage. In this case report, the stability of a palatal implant for distalization of molars bodily and for anchorage maintenance was assessed. The implant was a stepped screw titanium (4.5 mm diameter x 8 mm length), and it was placed in the palatal region for orthodontic purposes. A surgical template containing a metal drill housing was prepared. Angulation of the drill housing was controlled according to the radiologic tracing of the maxilla transferred to a plaster cast section in the paramedian plane. The implant was placed using a noninvasive technique (incision, flap, and suture elimination) and left transmucosally to facilitate the surgical procedure and to reduce the number of operations. The paramedian region was selected (1) to avoid the connective tissues of the palatine suture and (2) because it is considered to be a suitable host site for implant placement. After three months of healing, the implant was osseointegrated and orthodontic treatment was initiated. For molar distalization, the Keles Slider appliance was modified and, instead of a Nance button, a palatal implant was used for anchorage. The results showed that the molars were distalized bodily at five months, and no anchorage loss was observed. At the end of the treatment, the smile was improved, and an ideal Class I molar and canine relationship, an ideal overbite, and an ideal overjet were all achieved. In conclusion, palatal implants can be used effectively for anchorage maintenance and in space-gaining procedures. Use of a three-dimensional surgical template eliminated implant placement errors, reduced chair time, minimized trauma to the tissues, and enhanced osseointegration. This method can be used effectively to achieve distalization of molars bodily without anchorage loss.

Adolescent↗

Treatment of skeletal open bite with a device for rapid molar intrusion: a preliminary report.

An open bite is one of the most difficult malocclusions the clinician has to deal with. In recent years, interest has increased regarding mechanics that reduce dependency upon patient compliance for success. Some patient-independent mechanism for molar intrusion or vertical control is desirable. The rapid molar intruder (RMI) appliance consists of two elastic modules that are secured to orthodontic bands on the upper and lower first molars. Vertical forces from these modules typically produce intrusion of the permanent molars in four to six months. The RMI modules may be used in the mixed dentition or incorporated in full-fixed mechanics in the permanent dentition. To avoid buccal flaring of the molars, these modules should be attached to a transpalatal arch and a mandibular lingual arch. Case reports are provided to stimulate interest in further investigation of the properties of this appliance.

Adult↗

Maxillary molar intrusion with fixed appliances and mini-implant anchorage studied in three dimensions.

The intrusion of an overerupted maxillary molar using traditional orthodontic treatment is a real challenge. The aim of this study was to investigate the envelope of intrusive movements of a maxillary molar in cases using mini-implants as anchorage with partial or full-mouth fixed edgewise appliances. The cusp tips of the pretreatment and postintrusion dental casts were recorded by a three-dimensional (3D) digitizer. The 3D data of the serial dental casts were analyzed to distinguish the direction and magnitude of individual tooth movement. The mean intrusive movement of the maxillary first molars was three to four mm, with a maximum of over eight mm. For the adjacent maxillary second molars and second premolars, the amount of intrusion was two mm and 1-2 mm, respectively. This study demonstrated that significant true intrusion of maxillary molars could be obtained in a well-controlled manner by using fixed appliances with titanium mini-implants as bony anchorage.

Adolescent↗