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PubMed1997

Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. II. Furcation area.

The purpose of this study was to demonstrate the extent of deposits removed from within the furcation area of mandibular first molars following the use of curets with a modified blade and slim ultrasonic inserts in an in vitro model simulating a closed root debridement approach to furcation treatment. The furcation areas of 100 artificial mandibular first molars were uniformly coated with black model paint. The molars were fixed into a custom acrylic model, maintained in a firm position with modified occlusal splints, and the roots covered with a heavy rubber dam. The model was set in a mannequin and mounted on a dental chair recreating a clinical situation. Fifty molars (25 right, 25 left) were instrumented with the experimental curets and an equivalent number of molars with the ultrasonic inserts. An experienced dental hygienist completed all the instrumentation, spending 4 minutes on each molar. The molars were sectioned buccolingually from the crown apically to separate the roots, and areas in the internal surface of mesial and distal roots were analyzed to determine the percentage of deposits remaining using a computerized imaging routine system. A 2-factor analysis of variance was conducted to test for differences between both types of instruments. The curets produced furcation root surfaces with significantly less percentage of residual deposits than the ultrasonic inserts (P < 0.01). This study indicates the potential value of small bladed curets in debriding involved furcations during initial therapy and supportive periodontal therapy. The current findings should be corroborated in a clinical study.

Acrylic Resins↗
PubMed1998

The influence of endodontic infection on periodontal status in mandibular molars.

The purpose of the study was to investigate the influence of an endodontic infection on periodontal probing depth and presence of furcation involvement in periodontally-involved mandibular molars. All first and second mandibular molars in 100 patients were selected if at least one was root-filled or had a possible periapical radiolucency. The sample consisted of patients from a referral population at a periodontal clinic which represented an adult population with a mean age between 50 and 60 years. For mandibular molars with periapical destruction at both roots, mean periodontal probing depth was significantly greater compared to teeth without periapical destruction. Horizontal furcation depths > or =3 mm were significantly more frequent at mandibular molars with periapical destruction. It is suggested that a root canal infection in periodontitis-involved molars may potentiate periodontitis progression by spreading of endodontic pathogens through patent accessory canals and dentinal tubules. In conclusion, an endodontic infection in mandibular molars was found to be associated with additional attachment loss in the furcation area, and may thus be considered to be one of several risk factors influencing the prognosis of molars in periodontitis-prone patients.

Adult↗
PubMed2007

Mandibular first molar relation to variable lower face skeletal components.

OBJECTIVE: To evaluate the position of the mandibular first permanent molar in the mandible relative to several factors. MATERIALS AND METHODS: A total of 185 untreated Class I and Class II patients were randomly selected from a sample of 350 patients from a single office. The palatal and mandibular planes were related to Frankfort horizontal to create the interjaw or "B" angle. Age and the mesial contact of the mandibular first molars were used. The landmarks were projected at right angles to the Frankfort horizontal for effective mandibular dimension lengths. Actual-length dimensions were projected at right angles to the mandibular plane. Pearson product moment correlation coefficients were computed to evaluate the effect of age, cranial length, and mandibular contribution to the molar's sagittal position in the mandible. Significance was reported only when P < .05 to determine a 95% confidence level. RESULTS: Statistically significant positive correlations indicated that the mandibular molar is located more forward with increasing age, longer mandibular body length, and increasing posterior facial height. In contrast, significant negative correlations to the interjaw, mandibular plane, ramal inclination angles, and the linear ramal contribution corresponded to a more posterior position of the molar with increasing angles. CONCLUSIONS: The mandibular first permanent molar is located more anteriorly with an older patient, a longer mandibular body, greater posterior facial height, and an acute interjaw angle. In contrast, an increase in the forward tip of the ramus places the molar in a more posterior location.

Age Factors↗
PubMed2005

Effect of premolar and molar occlusal angle on feed digestibility, water balance, and fecal particle size in horses.

OBJECTIVE: To determine whether occlusal angle of the premolar and molar teeth (ie, molar occlusal angle) was associated with feed digestibility, water balance, or fecal particle size in adult horses. DESIGN: Observational study. ANIMALS: 40 pregnant mares ranging from 3 to 19 years old. PROCEDURE: The horses were randomly allocated to 1 of 5 feeding groups with 8 horses/group. Horses were sedated, and molar occlusal angle was measured with 2 methods. An oral examination was performed, and total number of dental abnormalities was recorded. Feed digestibility, water balance, and fecal particle size were measured 7 and 16 weeks later. RESULTS: Molar occlusal angle ranged from 6.3 degrees to 19.3 degrees and was not significantly associated with feed digestibility, water balance, or fecal particle size. The number of dental abnormalities was not associated with feed digestibility. Molar occlusal angle did not vary significantly with horse age. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that molar occlusal angles between 6 degrees and 19 degrees do not adversely affect feed digestibility, water balance, or fecal particle size in adult horses. Additionally, there was no association between age and molar occlusal angle.

Animals↗
PubMed2005

Rare courses of the mandibular canal in the molar regions of the human mandible: a cadaveric study.

The inferior alveolar artery, vein and nerve send some branches to the molar teeth via the mandibular canal to the mental foramen. The present study attempted to define the presence and course of the mandibular canal in the mandible with the alveolar process by macroscopic cadaveric dissection and computerized tomography (CT) in order to provide information that might prevent injuries to vessels and nerves at risk during root canal treatment. We identified the position of the mandibular canal within a 30% ratio of the distance from inferior border of mandible to the apices of the root for 39 out of 131 sides (mesial root of first molar, 20%; distal root of first molar, 22.6%; mesial root of second molar, 27.8% and distal root of second molar, 47%) on panoramic X-ray observation. In one cadaver (male, 64 years old), the root apex of the second molar was in close proximity to the upper bony mandibular canal. Macroscopic dissection and computerized tomography showed that the main trunks of the inferior alveolar artery, vein, and nerve were in tight contact with the apex of the second molar. These observations of the anatomic course of the mandibular canal will be important to consider during root canal treatment of mandibular teeth.

Adult↗
PubMed1977

The effect of early loss of primary molars on tooth eruption and space conditions. A longitudinal study.

In 186 children study casts were made at the age of 9, 11 and 13 years. The material was grouped according to early loss of primary molars and a comparison was made between children with and without early losses. Early loss was defined as follows: 1. extraction of the first primary molar between 7 1/2 and 9 1/2 years and/or extraction of the second primary molar between 7 1/2 and 10 1/2 years; 2. extraction of the first and/or second primary molar before 7 1/2 years of age. The following variables were studied: space conditions, dental stage for groups of teeth, eruption stage of single teeth. For the incisors the clinical crown length (CCL) was used as a measure of the eruption stage. The results showed that there was a tendency to later eruption and later onset of dental stages in cases without early losses when a comparison was made with investigations where this factor had not been taken into consideration. The second permanent molar erupted earlier in both jaws after early loss of the second primary molar. Children with loss of primary molars before 7 1/2 years developed more crowding than children without losses and losses after 7 1/2 years had little effect on the relative space.

Adolescent↗
PubMed1995

Rating the preventive indication for mandibular third-molar surgery. The appropriateness of the visual analogue scale.

The aim was to determine whether a visual analogue scale (VAS) is an appropriate way for general dental practitioners and oral surgeons to rate their judgement of the indication for therapy of asymptomatic mandibular third molars. Thirty general dental practitioners and 10 oral surgeons had to judge the need for removal of 36 third molars. They were also asked to estimate the strength of the indication for extraction on a VAS. To assess the reliability of the judgment, the 36 cases were duplicated. For each participant, two mean indication indices with 95% confidence limits were calculated, one index for molars proposed to be extracted and one index for molars proposed not to be extracted. Pearson's correlation coefficient was used to estimate the intra-examiner reliability and the correlation between the number of molars proposed for extraction and the mean indication index. The correlation between the number of molars proposed to be extracted and the mean indication index was high (p < 0.001). The intra-examiner reliability was also high, with a mean correlation coefficient of 0.72 for the general practitioners and 0.84 for the oral surgeons. No single judge presented any overlap for the 95% confidence limits for the mean indication index of teeth proposed to be extracted versus teeth proposed not to be extracted. These results indicate that the VAS seems to be an appropriate method for analyzing the judgements on a therapeutic strategy like extraction versus no intervention for asymptomatic mandibular third molars.

Adult↗
PubMed1998

Molar root furcation: morphometric and morphologic analysis.

The objective of the present study was a morphometric and morphologic analysis of maxillary and mandibular first and second molars using three different techniques. Measurements of 207 maxillary molars (105 first and 102 second molars) and 207 mandibular molars (110 first and 97 second molars) were measured; root length, radicular trunk length (RTL), mesiodistal and buccolingual diameters (BLD) at the cementoenamel junction, inter-radicular angle (IRA) width, and furcal roof area (FRA) were recorded. No significant statistical correlations were found for most of these measurements, the only exception being the relationship between IRA/FRA, IRA/BLD in maxillary molars, and IRA/RTL in the maxillary first molar. Morphologic examination was carried out by stereo microscopy, light microscopy of undecalcified sections, and scanning electron microscopy. All of these techniques showed the complexity of the furcation area with a large number of anatomic irregularities and plaque-retentive structures that could hamper adequate cleaning during periodontal treatment.

Humans↗
PubMedDate not supplied

Fracture strength of adhesively restored pulpotomized primary molars.

PURPOSE: To evaluate the cuspal fracture resistance of primary teeth restored with different adhesive techniques. METHODS: Eighty primary molars were selected for pulpotomy preparations. The molars were matched according to molar type (upper or lower, 1st or 2nd), and divided into four groups: Group 1: Pulpotomy cavity restored with IRM, Dispersalloy amalgam (Control); Group 2: IRM, Hydroxyline, Amalgambond Plus and Dispersalloy; Group 3: IRM, Hydroxyline, Prime & Bond 2.1 and Dyract; Group 4: IRM, Hydroxyline, Single Bond and Z100 resin composite. In Groups 2,3 & 4, Hydroxyline was placed over the IRM to avoid direct contact of the adhesives and resin with the IRM. All specimens were thermocycled (1000 cycles, 5-55 degrees C), and mounted in acrylic 2 mm apical to the CEJ. The molars were then tested for cuspal fracture strength using an Instron machine with tapered steel balls made to match the occlusal area of the primary molars tested. Repeated measures ANOVA and paired t-test were used to test the statistical significance of the results. RESULTS: Mean fracture loads in Newtons + S.D.) were as follows: G1: 1087 + 284; G2: 1371 + 434; G3: 1336 + 320; G4: 1404 + 312. The three bonded procedures significantly (P < 0.001) increased the resistance of the primary molars to fracture compared to the control group. There was no significant difference between the three bonded procedures. CONCLUSIONS: Bonded restorations of pulpotomized primary molars may be an alternative restorative procedure to stainless steel crowns.

Acid Etching, Dental↗
PubMed2000

Comparative study of third molar impaction in rural and urban areas of South-Western Nigeria.

This study was carried out in the urban and rural areas of Southwest Nigeria with the objective of comparing the pattern of third molar impaction. A total of two thousand four hundred (2,400) subjects aged 20 years and above were examined for third molar impaction and radiographs taken for all suspected cases. Analysis of the finding in this study revealed that there was an increase in the prevalence of third molar impaction in the urban areas (10.7%) when compared with the rural populations (1.1%). It could be demonstrated that third molar impaction is more of a problem of urban youths than the older age groups. Civilization and change of diet seemed to be responsible for the observed differences in third molar impaction in the two geographical areas. This study also revealed that mesioangular impaction of lower third molar and vertical impaction of upper third molar was the commonest respectively in both communities.

Adult↗
PubMed2002

Effect of thermocycling on the fracture strength of intact third molars stored for two different time periods.

OBJECTIVE: This study investigated the effect of thermocycling on the fracture strength of intact, extracted molars stored for two different intervals before testing. METHODS: Thirty-eight recently extracted molars and 38 molars stored for 1 to 5 years were each randomly separated to create four subgroups. One subgroup from each storage interval was thermocycled 1,000 times from 5 to 55 degrees C using 30-second dwell times, and then all teeth were fractured using a universal testing machine. RESULTS: Thermocycled recently extracted molars had significantly lower mean fracture strengths than nonthermocycled recently extracted molars (p < 0.001). No other pairwise comparisons were statistically significant. CONCLUSION: Thermocycling significantly reduced the fracture strength of recently extracted third molars. However, no significant differences in fracture strength were seen with molars stored for 1 to 5 years before thermocycling.

Hot Temperature↗
PubMed2000

Controlled, rapid uprighting of molars: a surprisingly simple solution the pivot arm appliance.

In orthodontic cases where the regional anatomy provides limited room for eruption, there is etiologically a higher occurrence of tipped/impacted second molars. Although second molar extraction with third molar replacement is a useful option, the "Pivot Arm Appliance" encourages the uprighting of the second molar as a preferred treatment. The most unique and important attribute of the "Pivot Arm Appliance" is the rotating tube. In cases of access limitation, the disto-occlusal surface of the molar presents as one area that is accessible. Other features of the "Pivot Arm Appliance" include: The position of the rotator tube delivers optimal rotational force through the pivoting action of the tube/arm complex. The "Pivot Arm Appliance" takes advantage of the efficiency and simplicity of a Class I lever system. The anatomical fulcrum being the dense cortical bone located anterior to the ascending ramus. The vertical spring system is compact, reliable and delivers gentle controlled force in rotational direction. The lingual location of the "Pivot Arm Appliance" does not hinder the function of the tongue, impinge on the soft tissue or interfere with normal masticatory function. The ease of placement of the rotator tube and subsequent insertion of the spring. It is well to note the uprighting appliance provides a very useful and practical approach to the unique problem of severely tipped second molars with limited buccal access. The "Pivot Arm Appliance" does not function only in these situations but can be used in all cases of second molar uprighting of a moderate to severe nature.

Adolescent↗
PubMed2002

[Complications after third molar extractions: retrospective analysis of 1,213 teeth].

BACKGROUND: This retrospective study was conducted to analyze per and postoperative complications associated with third molar extraction. Our objective was to determine the appropriate moment for extraction. MATERIAL AND METHODS: The study included 367 patients, selected randomly among the population treated between January 1992 and December 1996. A total of 1213 third molars were extracted: 603 under local anesthesia in 83 men and 136 women, mean age 24.9 years (range 11-70); 610 under general anesthesia in 44 men and 104 women, mean age 19.9 years (range 12-62 years). The patients were divided into three groups by age: 11-18 years, 19-30 years, and 31 years and over. Extractions were performed by senior (n=4) and junior (n=7) surgeons who used the same standard operative technique for all patients. RESULTS: The overall complication rate for extractions conducted under local anesthesia was 12.6% for lower third molars and 2% for upper third molars. The most frequent complication was secondary infection (3.6%) for the mandible and fracture of the tuberosity and bucco-sinus communication for the maxillary. The overall complication rate for extractions conducted under general anesthesia was 8.2% for lower third molars and 1.5% for upper third molars. Complications were more frequent, for the entire cohort, when the operator was less experienced, the subject was older, and the tooth was deeply embedded. DISCUSSION: These results are in agreement with data in the literature. Based on our experience, we propose extraction of third molars during adolescence when the x-ray indicates normal eruption cannot be expected due to lack of space or an abnormal position.

Adolescent↗
PubMed2003

Molar incisor hypomineralisation (MIH).

REVIEW: Molar Incisor Hypomineralisation (MIH) is defined as a hypomineralisation of systemic origin of one to four permanent first molars frequently associated with affected incisors. MIH molars are fragile and caries can develop very easily in those molars. Although MIH molars are well known by paediatric dentists and their occurrence is related in severe cases to major clinical problems, only limited data of the size of the problem are available. The prevalence of MIH ranges in the literature from about 3.6 to 25% and seems to differ in certain regions and birth cohorts. Unfortunately more complete comparable valid data are lacking at the moment. It seems that several aetiological factors can cause the enamel defects and that their occurrence is child related. CONCLUSION: For children with repeated illnesses in the first years after birth and children with opacities on erupted molars or incisors it seems useful to increase the frequency of dental check-ups during the period of erupting first permanent molars.

Child↗
PubMedDate not supplied

Quantitative assessment of enamel hypomineralization by KaVo DIAGNOdent at different sites on first permanent molars of children in China.

PURPOSE: The purpose of this study was to identify the most caries-susceptible site of pits and fissures on first permanent molars by quantitative evaluation of the mineralization in both caries-active and caries-free children, and to provide helpful information for cost-effective, targeted prevention. METHODS: Eighty-four caries-free and 85 caries-active children were selected from 800 6- to 7-year-old children with fully erupted first permanent molars. Hypomineralization of the central fossa (CF) and lingual pit (LP) of the maxillary or buccal pit (BP) of mandibular first permanent molars were evaluated by KaVo DIAGNOdent. Statistical analysis included grouped t test and single-factor variance analysis and paired comparison. RESULTS: CF of mandibular first permanent molars had significantly greater hypomineralization than other sites. The hypomineralization of the maxillary CF is more severe than that of LP. The extent of the hypomineralization of each site at the first permanent molar in caries-active children was significantly higher than that in caries-free children. CONCLUSIONS: Central fossae of first mandibular molars are the most hypomineralized sites in both caries-free and caries-active groups. The results suggest that preventive interventions should be targeted at the CF of mandibular molars with special concern given to the caries-active population.

Analysis of Variance↗
PubMed2003

Occlusal molar surfaces in females with Turner's syndrome.

The aim of this study was to identify the molar occlusal features in 73 subjects with the Turner's syndrome (TS) and compared to a control group (CG) of 322 healthy females. The occlusal features were scored on dental plaster casts using the Scoring Procedures for Key Morphological Traits of the Permanent Dentition: The Arizona State University Dental Anthropology System (ASU). The results were analyzed through frequency, percentage and chi 2-test. TS subjects have more frequent reduction of cusp number, distolingual cusp on the upper molars and distal cusp on the lower molar, with the consequent reduction of the occlusal surface. Reduced size of occlusal surface and number cusps on upper molars resulted in the transformation of rhomboid occlusal shape into triangular, with the consequent loss of H-shaped groove system (in the upper right first molars H-shaped groove system was significantly less frequently found in TS (p < 0.05); in the upper left second molars H-shaped groove system was significantly less frequently found in TS (p < 0.01). The X-chromosome aneuploidy can cause a decrease in developmental homeostasis, which results in the alteration of apposition of the enamel and in consequently substantial changes of the molar occlusal morphological features.

Dental Occlusion↗
PubMed2004

New considerations in the treatment of compromised third molars.

Management of asymptomatic malposed third molars is a controversial topic. As a result, many malposed or mildly pathologic third molars are not removed. Historical pro and con arguments regarding removal centered around cost and the aspects of the surgical removal itself. Current epidemiology and medical advances address issues not considered before. There is a large growth of the aging population (over 40 years). More and more of these elderly patients are requiring third molar removal. Over a five-year period, 1997-2002, the incidence almost doubled to 17.9 percent. This age category is known to be high risk for third molar surgery. An equally or higher risk is the rapidly growing number of patients seeking third molar surgery who are moderately severely medically compromised. This paper reviews how this lack of consensus results in delayed removal of malposed third molars in this population. Preventive dental concepts, removing compromised third molars earlier, would eliminate the high risk to this aging population.

Adult↗
PubMed2005

[Effects of fluoride drop or fluoride ion infiltration in toddler period on demineralization of first permanent molar of children].

OBJECTIVE: To observe the effect of fluoride drop or fluoride ion infiltration on demineralization of the first permanent molar of children. METHODS: 45 children applied by fluoride drop over 3 years in Chengdu and 40 controls were selected. 45 children applied by fluoride ion infiltration more than 3 years in Xiamen and 40 controls were selected in this study. Demineralization of the different sites of the first permanent molar was evaluated by KaVo DIAGNOdent. The effect of FD and FII in toddler period on demineralization of the first permanent molar was evaluated. RESULTS: Early demineralization of the first permanent molar in children without fluoride drop were more severe than that of children with fluoride drop in toddle period (P < 0.01). There was no significantly difference between demineralization of first permanent molar in children with fluoride ion infiltration and control group (P > 0.05). CONCLUSION: Fluoride drop in toddle period can help the remineralization of newly erupted first permanent molar of children. There is no effect of fluoride ion infiltration on demineralization of newly erupted first permanent molar of children.

Child↗