Impacts of Skeletal Anterior Open Bite Malocclusion on Speech

INTRODUCTION

Articulation problems are seen in 80-90% of dentofacial deformity (DFD) subjects compared with 5% of the general population, impacting communication and quality of life, but the causal link is unclear. We hypothesize there are both qualitative (perceptual) and quantitative (spectral) differences in properties of stop (/t/ or /k/), fricative (/s/ or /∫/), and affricate (/t∫/) consonant sounds and that severity of anterior open bite (AOB) jaw disharmonies correlates with degree of speech abnormality.

METHODS

To test our hypotheses, surgical orthodontic records and audio recordings were collected from DFD patients (n=39 AOB, 62 controls). A speech pathologist evaluated subjects and recordings were analyzed using spectral moment analysis (SMA) to measure sound frequency distortions.

RESULTS

Perceptually, there is a higher prevalence of auditory and visual speech distortions in AOB DFD patients when compared to controls. Quantitatively, a significant (p<0.01) increase in the centroid frequency (M1) was seen in the /k/, /t/, /t∫/, and /s/ sounds of AOB subjects compared to the controls. Using linear regression, correlations between AOB skeletal severity and spectral distortion were found for /k/ and /t/ sounds.

CONCLUSIONS

A higher prevalence of qualitative distortion and significant quantitative spectral distortions in consonant sounds were seen in AOB patients compared to controls. Additionally, severity of skeletal AOB is correlated with degree of distortion for consonant sounds. These findings provide insight into how the surgical and/or orthodontic treatment of AOB may impact speech.

Modified Carnoy's Compared to Carnoy's Solution Is Equally Effective in Preventing Recurrence of Odontogenic Keratocysts

PURPOSE

Carnoy's solution (CS), the gold standard for adjunctive chemical cautery in treatment of odontogenic keratocysts (OKCs), has been banned for 7 years, leading to substitution with the non-chloroform containing modified Carnoy's solution (MC) without data to support its effectiveness. We performed this study to compare the earlier data with CS to the more current outcomes with MC.

METHODS

A retrospective cohort study was conducted on patients diagnosed with OKC and treated by a single surgeon (GHB) with enucleation and curettage (EC), peripheral ostectomy, and application of CS or MC. The primary predictor variables were use of CS or MC. The primary outcome variables were recurrence (yes vs. no) and time to recurrence. Secondary variables included demographics, anatomic location, and whether teeth adjacent to the lesion were extracted. Statistical analyses included chi-squared test/Fisher's exact test, Wilcoxon rank sum test, and Kaplan-Meier curves.

RESULTS

77 patients, 36 patients in the CS group and 41 in the MC group, met inclusion criteria, including at least 1 year of follow-up time. Characteristics of the groups were similar: median age 41.5 and 46, 61% and 71% male gender, 81% and 90% posterior, and 64% and 50% mandibular lesions, respectively. Overall recurrence was similar, 14.29%, with 5 (13.9%) recurrences in the CS group and 6 (14.6%) in the MC group (P = 0.92). Median time to recurrence was 24 months for both groups. Preserving adjacent teeth was associated with a significant increase in recurrence (P = 0.0036).

CONCLUSION

Based on this comparison of retrospective outcome data, we found no significant difference in recurrence rate or distribution of time to recurrence between OKCs treated with CS or MC. Aggressiveness of surgical technique is likely a predictive factor in recurrence rate. Future studies should focus on prospective studies and continuing follow-up of the MC group.

Double-Blind, Randomized Clinical Trial Comparing One Percent Buffered Versus Two Percent Unbuffered Lidocaine Injections in Children

Purpose: Buffered local anesthetics offer an alternative to conventional, unbuffered anesthetic formulations; however, evidence about their use in children is scant. The purpose of this study was to determine the anesthetic and physiologic differences associated with the use of buffered one percent and unbuffered two percent lidocaine (both with 1:100,000 epinephrine) in children. Methods: In this randomized, double-blinded, crossover study, 25 children ages 10 to 12 years old received two inferior alveolar never blocks, at least one week apart, randomized to alternating sequences of two drug formulations: (1) formula A-three mL buffered one percent lidocaine (i.e., including 0.3 mL of 8.4 percent sodium bicarbonate); or (2) formula B-three mL unbuffered two percent lidocaine. Primary outcomes were mean blood lidocaine levels (15 minutes post-injection), timing of clinical signs onset, response to pain on injection, and duration of anesthesia. Analyses relied upon analysis of variance for crossover study designs and a P<0.05 statistical significance criterion. Results: The buffered formulation resulted in significantly lower mean blood lidocaine levels compared to unbuffered-a 63 percent (P<0.05) weight-adjusted relative decrease. The authors found no important differences in pain upon injection, onset, and duration of anesthesia. Conclusion: The buffered local anesthetic formulation showed equal effectiveness with a double-concentration unbuffered formulation while resulting in lower mean blood lidocaine levels-an important gain for the prevention of anesthetic toxicity.

Exploring the resilience of wheat crops grown in short rotations through minimising the build-up of an important soil-borne fungal pathogen

Given the increasing demand for wheat which is forecast, cropping of wheat in short rotations will likely remain a common practice. However, in temperate wheat growing regions the soil-borne fungal pathogen Gaeumannomyces tritici becomes a major constraint on productivity. In cultivar rotation field experiments on the Rothamsted Farm (Hertfordshire, UK) we demonstrated a substantial reduction in take-all disease and grain yield increases of up to 2.4 tonnes/ha when a low take-all inoculum building wheat cultivar was grown in the first year of wheat cropping. Phenotyping of 71 modern elite wheat cultivars for the take-all inoculum build-up trait across six diverse trial sites identified a few cultivars which exhibited a consistent lowering of take-all inoculum build-up. However, there was also evidence of a significant interaction effect between trial site and cultivar when a pooled Residual Maximum Likelihood (REML) procedure was conducted. There was no evidence of an unusual rooting phenotype associated with take-all inoculum build-up in two independent field experiments and a sand column experiment. Together our results highlight the complex interactions between wheat genotype, environmental conditions and take-all inoculum build-up. Further work is required to determine the underlying genetic and mechanistic basis of this important phenomenon.

A multimodal analgesic protocol may reduce opioid use after third molar surgery: A pilot study

OBJECTIVE

This study was designed to assess the number of opioid doses available to patients from filled prescriptions after adoption, in 2017, of a multimodal analgesic protocol that included opioid prescribing to manage postoperative pain.

STUDY DESIGN

Data were retrieved from records of the first 24 patients having third molar surgery in 2017 identified from appointment schedules. Inclusion criteria were American Society of Anesthesiologists risk classification I or II, age 18 to 35 years, and at least 2 lower third molars removed. The exclusion criterion was being treated for opioid addiction/abuse. The primary outcome variable was the number of opioid doses filled by prescriptions at each patient's discretion. The primary predictor variable was the multimodal analgesic protocol.

RESULTS

Data from records of 24 consecutive patients were analyzed; 83% were females. Median age was 25 years (interquartile range [IQR] 12-29 years). Median surgery time was 35 minutes (IQR 27-32 minutes). The median number of opioid doses filled in 2017 was 4 (IQR 0-4).

CONCLUSIONS

The outcomes from this pilot study suggest that implementation of a multimodal analgesic protocol to manage postoperative pain, while limiting the number of opioid doses available to the patient, may be an effective strategy for a wider range of patients and procedures.

Buffered 1% Lidocaine With Epinephrine Can Be as Effective as Nonbuffered 2% Lidocaine With Epinephrine for Maxillary Field Block

PURPOSE

Buffering local anesthetics with epinephrine (Epi) offers clinicians options not often considered. This study assessed outcomes for pulpal anesthesia, pain on injection, and time to midface numbness for buffered 1% lidocaine with 1:100,000 Epi versus nonbuffered 2% lidocaine with 1:100,000 Epi.

MATERIALS AND METHODS

In this trial with a randomized, crossover design, buffered 1% lidocaine was compared with nonbuffered 2% lidocaine. Subjects were adult volunteers who served as their own controls. The predictor variables were alternate drug formulations. The outcome variables were subjects' responses to cold and electric pulp testing (EPT) stimulation of the maxillary first molar and canine, pain levels during the injection, and time to midface numbness. After maxillary field blocks with 40 mg of buffered lidocaine or 80 mg of nonbuffered lidocaine, subjects reported pain on injection and responses of the maxillary first molar and canine after cold and EPT stimulation. Teeth were tested before field block and at 30-minute intervals until a positive response was detected. Two weeks later, subjects were tested with the alternate drug combinations. For all outcome variables, assessment of treatment difference, calculated as 1% buffered minus 2% nonbuffered, was performed with the Wilcoxon rank sum test with significance at P < .05.

RESULTS

More of the 24 subjects were women and Caucasian. The median age was 23.5 years (interquartile range, 21, 25 years), and the median body weight was 155 lb (interquartile range, 128.5, 176.5 lb). Pain levels during the injection were significantly lower for 1% buffered lidocaine, with P = .04. Times to response after injection were not significantly different between the 2 drug formulations for the cold test on a molar, with P = .08, or the cold test on a canine, with P = .22. However, times to response were significantly longer for nonbuffered drugs for EPT on the molar and canine, both with P = .01.

CONCLUSIONS

Buffering 1% lidocaine with 1:100,000 Epi reduces the pain on injection with a maxillary field block and results in similar lengths of pulpal anesthesia tested with a cold stimulus as compared with nonbuffered 2% lidocaine with 1:100,000 Epi.

Buffered 1% Lidocaine With Epinephrine Is as Effective as Non-Buffered 2% Lidocaine With Epinephrine for Mandibular Nerve Block

PURPOSE

To assess outcomes for pulpal anesthesia and pain on injection for buffered 1% lidocaine with 1:100,000 epinephrine (EPI) versus non-buffered 2% lidocaine with 1:100,000 EPI.

PATIENTS AND METHODS

In a randomized cross-over trial approved by the institutional review board, buffered 1% lidocaine with 1:100,000 EPI was compared with non-buffered 2% lidocaine with 1:100,000 EPI. After mandibular nerve block with buffered lidocaine 40 mg or non-buffered lidocaine 80 mg, patients reported responses at the mandibular first molar and canine after cold and electrical pulp testing (EPT). Patients also reported pain on injection with a 10-point Likert-type scale. Teeth were tested before nerve block and at 30-minute intervals until a positive response returned. Two weeks later, patients were tested with the alternate drug combinations. The same outcomes were assessed. Predictor variables were alternate drug formulations. Outcome variables were patients' responses to cold and EPT stimulation of the mandibular first molar and canine and pain on injection. An assessment of treatment difference was performed using Wilcoxon rank-sum tests with Proc NPAR1WAY (SAS 9.3, SAS Institute, Cary, NC). Significance was set at a P value less than .05.

RESULTS

Fifty-seven percent of patients were women and 43% were men. Seventy percent were Caucasian, 17% were African American, and 13% had another ethnicity. Median age was 25 years (interquartile range [IQR], 21-26 yr) and median body weight was 140 lbs (IQR, 120-155 lbs). After the cold test and EPT, the time to sensation return for the molar or canine was not statistically different between the 2 drug formulations. Patients reported significantly lower pain scores with the buffered versus non-buffered drug (P < .01).

CONCLUSIONS

After mandibular nerve block, buffered 1% lidocaine with EPI can produce similar clinical outcomes for duration of pulpal anesthesia as non-buffered 2% lidocaine with EPI and lower pain on injections, which are a potential benefit to patients.

Buffered Versus Non-Buffered Lidocaine With Epinephrine for Mandibular Nerve Block: Clinical Outcomes

PURPOSE

Outcomes for peak blood levels were assessed for buffered 2% lidocaine with 1:100,000 epinephrine compared with non-buffered 2% lidocaine with 1:100,000 epinephrine.

PATIENTS AND METHODS

In this institutional review board-approved prospective, randomized, double-blinded, crossover trial, the clinical impact of buffered 2% lidocaine with 1:100,000 epinephrine (Anutra Medical, Research Triangle Park, Cary, NC) was compared with the non-buffered drug. Venous blood samples for lidocaine were obtained 30 minutes after a mandibular nerve block with 80 mg of the buffered or unbuffered drug. Two weeks later, the same subjects were tested with the alternate drug combinations. Subjects also reported on pain on injection with a 10-point Likert-type scale and time to lower lip numbness. The explanatory variable was the drug formulation. Outcome variables were subjects' peak blood lidocaine levels, subjective responses to pain on injection, and time to lower lip numbness. Serum lidocaine levels were analyzed with liquid chromatography-mass spectrometry. Statistical analyses were performed using Proc TTEST (SAS 9.3; SAS Institute, Cary, NC), with the crossover option for a 2-period crossover design, to analyze the normally distributed outcome for pain. For non-normally distributed outcomes of blood lidocaine levels and time to lower lip numbness, an assessment of treatment difference was performed using Wilcoxon rank-sum tests with Proc NPAR1WAY (SAS 9.3). Statistical significance was set at a P value less than .05 for all outcomes.

RESULTS

Forty-eight percent of subjects were women, half were Caucasian, 22% were African American, and 13% were Asian. Median age was 21 years (interquartile range [IQR], 20-22 yr), and median body weight was 147 lb (IQR, 130-170 lb). Median blood levels (44 blood samples) at 30 minutes were 1.19 μg/L per kilogram of body weight. Mean blood level differences of lidocaine for each patient were significantly lower after nerve block with the buffered drug compared with the non-buffered agent (P < .01). Mean score for pain on injection for nerve block (n = 46 scores) was 3.3 (standard deviation, 0.9). Seventy-eight percent of subjects reported lower or the same pain scores with the buffered drug; 61% of subjects reported a shorter time to lower lip numbness with the buffered drug.

CONCLUSIONS

Buffering 2% lidocaine with epinephrine can produce clinical outcomes favorable for subjects and clinicians without clinically detrimental peak blood lidocaine levels.

Special Contribution: Third Molar Clinical Trials Annotated Bibliography

PURPOSE

To provide clinicians with an annotated bibliography of published articles from research funded externally by the Oral and Maxillofacial Surgery Foundation, spanning 1996 to 2015, addressing the topic of third molar management.

MATERIALS AND METHODS

A brief summary for each article was generated by the respective authors.

RESULTS

The complete annotated bibliography generated by the authors is included in the Appendix.

CONCLUSION

The annotated bibliography provides clinicians and other interested individuals with a summary of current literature emanating from clinical studies on third molar topics.

Combined surgical-orthodontic treatment: how did it evolve and what are the best practices now?

It has been 50 years since the landmark presentation by Hugo Obwegeser at Walter Reed Army Hospital. At that conference, Professor Obwegeser offered American surgeons techniques to correct facial skeletal deformities with access through intraoral incisions. As important advances in surgical technique and anesthesia evolved for the surgical procedures, a major contribution by American orthodontists in collaboration with surgeons was the creation of a common diagnostic, planning, and treatment scheme for use by both clinician groups in the treatment of dentofacial deformities, the skeletal and dental problems of the most severely affected 5% of the population. This article summarizes what American orthodontists and surgeons have learned in the late 20th and early 21st centuries, and forecasts what might be the future of treatment for patients with dentofacial deformities.

Effects of break crops, and of wheat volunteers growing in break crops or in set-aside or conservation covers, all following crops of winter wheat, on the development of take-all (Gaeumannomyces graminis var. tritici) in succeeding crops of winter wheat

Experiments on the Rothamsted and Woburn Experimental Farms studied the effects on take-all of different break crops and of set-aside/conservation covers that interrupted sequences of winter wheat. There was no evidence for different effects on take-all of the break crops per se but the presence of volunteers, in crops of oilseed rape, increased the amounts of take-all in the following wheat. Severity of take-all was closely related to the numbers of volunteers in the preceding break crops and covers, and was affected by the date of their destruction. Early destruction of set-aside/conservation covers was usually effective in preventing damaging take-all in the following wheat except, sometimes, when populations of volunteers were very large. The experiments were not designed to test the effects of sowing dates but different amounts of take-all in the first wheats after breaks or covers apparently affected the severity of take-all in the following (second) wheats only where the latter were relatively late sown. In earlier-sown second wheats, take-all was consistently severe and unrelated to the severity of the disease in the preceding (first) wheats. Results from two very simple experiments suggested that substituting set-aside/conservation covers for winter wheat, for 1 year only, did not seriously interfere with the development of take-all disease or with the development or maintenance of take-all decline (TAD). With further research, it might be possible for growers wishing to exploit TAD to incorporate set-aside/conservation covers into their cropping strategies, and especially to avoid the worst effects of the disease on grain yield during the early stages of epidemics.

Monitoring for periodontal inflammatory disease in the third molar region

PURPOSE

To assess changes at 2-year intervals in the periodontal status of the third molar region in participants enrolled with asymptomatic third molars and no clinical evidence of third molar region periodontal pathology.

PARTICIPANTS AND METHODS

The included participants who presented with a healthy periodontal status (all probing depths [PDs], <4 mm) in the third molar region, defined as distal of second molars and around adjacent third molars, were from a larger longitudinal study of participants with asymptomatic third molars. Full-mouth periodontal PD data from 6 sites per tooth were obtained clinically at enrollment and at subsequent 2-year intervals. Data were aggregated to the patient level. Outcome variables were the presence or absence of periodontal pathology, defined as at least 1 PD of at least 4 mm in the third molar region.

RESULTS

One hundred twenty-nine participants had a third molar region PD shallower than 4 mm at enrollment. Most participants were Caucasian (85%), women (60%), younger than 25 years (62%), educated beyond high school (84%), and with good oral health habits. At 6 years, excluding the 61 participants lost to follow-up, 47% participants had had third molars removed, 21% had developed at least 1 PD of at least 4 mm in the third molar region since enrollment, and 32% retained the periodontal status at enrollment (all PDs in third molar region, <4 mm). Demographic characteristics were not statistically different for participants followed for 6 years compared with those lost to follow-up.

CONCLUSIONS

Although not all participants could be followed for 6 years after enrollment or chose to retain third molars, one third of participants maintained the third molar region periodontal status assessed at baseline for 6 years after enrollment; no clinical evidence of pathology developed over time.

Pain with pericoronitis affects quality of life

PURPOSE

To assess the association between patients' pericoronitis pain symptoms and quality-of-life (QOL) outcomes for lifestyle and oral function.

PATIENTS AND METHODS

Subjects (American Society of Anesthesiologists health risk assessment level I or II) with mild symptoms of pericoronitis were enrolled in a study approved by the institutional review board and asked to complete a QOL instrument specifically for third molar problems covering lifestyle, oral function, and pain. Subjects assessed lifestyle and oral function using a 5-point Likert-type scale, ranging from "no trouble" (score, 1) to "lots of trouble" (score, 5), and worst and average pain using a 7-point Likert-type scale, ranging from "no pain" (score, 1) to "worst pain imaginable" (score, 7). Pain levels reported at enrollment were compared with QOL outcomes for lifestyle and oral function using Spearman correlation coefficients. Correlations of at least 0.6 were considered clinically quite important, and correlations of at least 0.4 were considered clinically important. Associations between these outcome measurements were considered statistically significant at a P value less than .05.

RESULTS

Most of the 113 subjects were Caucasian (51%), women (56%), 23 years old or younger (58%), and well educated (91% with at least some college). Mean pain levels ± standard deviation were low (worst pain, 3.3 ± 1.5; average pain, 2.4 ± 1.2). All pain outcomes were significantly associated with items in the lifestyle and oral function domains (P < .01). Clinically important correlations were seen between pain outcomes and daily routine, social life, eating a regular diet, chewing food, and talking (P < .0001).

CONCLUSIONS

Clinically important correlations existed between subjects' pericoronitis pain and lifestyle and oral function, associations not often considered by clinicians or policy makers.

Are bioresorbable polylactate devices comparable to titanium devices for stabilizing Le Fort I advancement?

The purpose of this study was to evaluate whether skeletal and dental outcomes following Le Fort I surgery differed when stabilization was performed with polylactate bioresorbable devices or titanium devices. Fifty-seven patients with preoperative records and at least 1 year postoperative records were identified and grouped according to the stabilization method. All cephalometric X-rays were traced and digitized by a single operator. Analysis of covariance was used to compare the postsurgical change between the two stabilization methods. Twenty-seven patients received bioresorbable devices (group R), while 30 received titanium devices (group M). There were no statistically significant differences between the two groups with respect to gender, race/ethnicity, age, or dental and skeletal movements during surgery. Subtle postsurgical differences were noted, but were not statistically significant. Stabilization of Le Fort I advancement with polylactate bioresorbable and titanium devices produced similar clinical outcomes at 1 year following surgery.

Effect of quality of life measures on the decision to remove third molars in subjects with mild pericoronitis symptoms

PURPOSE

To assess how quality of life (QoL) measures affect the decision for third molar (3M) removal in patients with mild symptoms of pericoronitis.

PATIENTS AND METHODS

Healthy subjects, aged 18 to 35 years, with mild symptoms of pericoronitis were enrolled in an institutional review board-approved study. The demographic, clinical, and QoL data were collected at enrollment. The subjects voluntarily scheduled surgery for 3M removal. The principal outcome variable was their decision to undergo or not undergo surgery within 6 months of enrollment. The possible predictor variables in a multivariate logistic regression analysis were the demographic characteristics, dental insurance, and QoL measures.

RESULTS

The mean age of the 113 subjects was 23.2 ± 3.8 years. Of the 113 subjects, 79 elected to undergo 3M removal within 6 months of enrollment (removed group) and 34 elected to retain their 3M at 6 months after enrollment (retained group). A significantly greater proportion of the removed group were white (58% vs 35%; P = .03) and reported having at least "a little trouble" with opening their mouths (38% vs 18%; P = .04) and taking part in social life (27% vs 6%; P = .01). The multivariate logistic regression model suggested the odds of electing 3M removal within 6 months of enrollment were greater for those who were white (odds ratio [OR] 2.69, 95% confidence interval [CI] 1.14 to 6.32) and those who had at least "a little trouble" with interactions in their social life (OR 3.22, 95% CI 1.08 to 9.58).

CONCLUSIONS

In subjects with mild pericoronitis symptoms, experiencing problems with oral function and lifestyle, factors not often considered by clinicians, were significantly associated with subjects' decision for early 3M removal.

Removal of symptomatic third molars may improve periodontal status of remaining dentition

PURPOSE

To assess the impact of third molar removal on the periodontal status of adjacent second molars and teeth more anterior in the mouth in patients with mild symptoms of pericoronitis.

PATIENTS AND METHODS

Healthy patients with mild symptoms of pericoronitis affecting at least 1 mandibular third molar were recruited for a study approved by the institutional review board. The subset analyzed in this study had all 4 third molars removed. Data were collected at enrollment and at least 3 months after surgery. Full-mouth periodontal probing was conducted at 6 sites per tooth. A probing depth of at least 4 mm (PD4+) was considered an indicator for periodontal pathology. The presence of a PD4+ on the distal of second molars (D2Ms) or anterior to the D2Ms, the number of PD4+s, and extent scores (percentage of PD4+s of all possible probing sites) were assessed at the patient and jaw levels. The association between patients' pre- and postsurgical periodontal status was assessed using the McNemar exact test. The level of significance was set at .05.

RESULTS

The median age of the 69 patients was 21.8 years (interquartile range, 20.2 to 25.2 yr). Forty-five percent were men, and 57% were Caucasian. Significantly more patients (88%) had at least 1 D2M PD4+ at enrollment compared with after surgery (46%; P < .01). D2M extent scores decreased from 31.5 at enrollment to 11 after surgery. Significantly more patients (61%) had at least 1 PD4+ anterior to the D2M at enrollment compared with after surgery (29%; P < .01). Extent scores anterior to the D2M decreased from 2.0 at enrollment to 0.6 after surgery.

CONCLUSIONS

Removal of third molars in patients with mild pericoronitis symptoms improved the periodontal status of the D2Ms and teeth more anterior in the mouth.

The presence of visible third molars negatively influences periodontal outcomes in the Maternal Oral Therapy to Reduce Obstetric Risk study

PURPOSE

To assess the relationship between the presence or absence of visible third molars and outcomes for periodontal inflammatory disease.

METHODS

Obstetric subjects, at enrollment in an institutional review board-approved, multisite study, Maternal Oral Therapy to Reduce Obstetric Risk (N = 1,798), were divided into 2 groups, those with no visible third molars (n = 692) and those with at least 1 visible third molar (n = 1,106), the predictor variables for this study. The principal outcome variables were the patient-level periodontal status of the first/second molars: mean periodontal probing depths, mean attachment levels, and mean extent scores. Periodontal disease severity also was assessed by criteria from the Oral Conditions and Pregnancy trial and the Centers for Disease Control and Prevention/American Academy of Periodontology. Outcomes according to the presence or absence of third molars were compared with χ(2) statistics and multivariable analyses. Significance was set at P < .05.

RESULTS

Significantly more subjects had at least 1 third molar (62%) as compared with subjects with no visible third molar (38%) (P < .01). Ethnic characteristics of the 2 groups were similar. Overall, more subjects were white (61%), with most identifying their ethnicity as Latino. African-American subjects were well represented (37%). Subjects with a visible third molar were more likely to be significantly older, to be receiving medical assistance, and to have used tobacco before pregnancy. If subjects had at least 1 visible third molar, the mean first/second molar probing depths, attachment levels, and scores for bleeding on probing were significantly greater even after adjustment for covariates. On the basis of either Oral Conditions and Pregnancy criteria or Centers for Disease Control and Prevention/American Academy of Periodontology criteria, subjects were significantly more likely to have moderate or severe periodontal disease if a third molar was detected.

CONCLUSION

If at least 1 visible third molar was detected in subjects in the Maternal Oral Therapy to Reduce Obstetric Risk study at enrollment as compared with no detected third molars, periodontal outcomes were significantly worse.

Mechanical debridement of subgingival biofilm in participants with asymptomatic third molars does not reduce deeper probing depths in the molar regions of the mouth

PURPOSE

To assess the impact of mechanical debridement of subgingival biofilm on periodontal outcomes in adolescents and young adults with asymptomatic third molars.

METHODS

Healthy participants with 4 asymptomatic third molars were enrolled in an institutional review board-approved longitudinal study. Clinical data were collected at enrollment and at follow-up visits. Full-mouth periodontal probing, 6 sites per tooth, was assessed as a measure of clinical periodontal status. At enrollment, all participants had dental prophylaxis after data collection, which included removal of subgingival biofilm; this was repeated annually. The primary outcome measures were the comparison from baseline to follow-up 2 years after enrollment of participants' periodontal probing depths for third molars and first/second molars. In addition, a comparison of extent scores at baseline to follow-up 2 years after enrollment for periodontal probing sites of at least 4 mm was performed for the same molar regions of the mouth. Changes over time in clinical periodontal status from enrollment to the follow-up at least 2 years later were analyzed with Mantel-Haenszel row mean score statistics. The level of significance was set at P < .05.

RESULTS

The median follow-up from entry to the study was 2.2 years (interquartile range, 2.0-2.8 years) for 262 participants who averaged 27.7 years of age (SD, 1.2 years); 53% were female participants, and 81% were white. Most participants (90%) were educated beyond high school. On the basis of periodontal probing depths, participants' clinical periodontal status did not differ from enrollment to follow-up.

CONCLUSIONS

Dental prophylaxis at yearly intervals in participants with asymptomatic third molars, which included mechanical removal of subgingival biofilm, had minimal or no impact on reducing deeper probing depths, clinical indicators of periodontal pathology in young adults.

The association between orthodontic treatment with removal of premolars and the angulation of developing mandibular third molars over time

OBJECTIVE

To assess changes in mandibular third molar angulation during orthodontic treatment in subjects having either first or second premolars or neither removed.

MATERIALS AND METHODS

In a retrospective study approved by the institutional review board, right and left mandibular third molar angulations were compared to the vertical axis of adjacent second molars before and at the end of orthodontic treatment. The sample included 25 subjects with first premolars removed, 25 subjects with second premolars removed, and 24 subjects with no premolars removed. A decrease in angulation over time of at least 5°, so that the third molar became more vertical, was considered clinically favorable. Data were assessed by a linear mixed effect model and a proportional odds model with significance set at P < .05.

RESULTS

Prior to treatment, the average mandibular third molar angulation did not differ significantly among the three study groups (P  =  .97). The average change during treatment was not significantly affected by group (P  =  .59), but a higher proportion of mandibular third molars were more vertical by at least 5° in the second premolar extraction group compared to the other two groups at the completion of treatment.

CONCLUSION

Although creating space for third molars to erupt and function has intuitive appeal, clinicians should not assume that third molars will move upright to a vertical position even if premolar removal is performed as part of an orthodontic treatment plan.

Quality of life outcomes after third molar removal in subjects with minor symptoms of pericoronitis

PURPOSE

Our purpose was to assess the effect of third molar removal on the quality of life in subjects with symptoms of pericoronitis.

PATIENTS AND METHODS

Healthy subjects (American Society of Anesthesiologists Classes I and II), aged 18 to 35 years, with minor symptoms of pericoronitis affecting at least 1 mandibular third molar were recruited for an institutional review board-approved study. The exclusion criteria were major symptoms of pericoronitis, generalized periodontal disease, body mass index greater than 29 kg/m(2), and antibiotic or tobacco use. The data from patients undergoing surgery to remove all third molars with a follow-up examination after surgery at least 3 months later were included in these analyses. The clinical, demographic, and quality of life data were collected at enrollment and after surgery. At entry, the debris was removed from symptomatic third molar sites; no attempt was made to mechanically remove nonsheddable biofilm. The patients scheduled surgery electively with a recall examination at least 3 months after surgery.

RESULTS

The median age of the 60 subjects was 21.9 years (interquartile range 20.2 to 24.7). The median postoperative follow-up was 7.7 months (interquartile range 6.0 to 12.4). The proportion of patients reporting the worst pain as severe decreased from enrollment to after surgery from 32% to 3%. Those responding "none" for the worst pain increased from 10% to 78%. Fifteen percent of subjects reported the pain intensity as "nothing," "faint," or "very weak" at enrollment. This increased to 96% after surgery. One third of patients reported the unpleasantness of pain as "neutral," "slightly unpleasant," or "slightly annoying" at enrollment, which increased to 97% after surgery. Also, 22% and 18% of the patients reported "quite a bit" or "lots of difficulty" with eating desired foods and chewing foods at enrollment, respectively; only 1 patient reported this degree of difficulty at the follow-up examination. In contrast, 42% and 37% of the patients reported no difficulty with eating and chewing at enrollment, which had increased to 95% and 93% at the follow-up examination, respectively.

CONCLUSIONS

Removal of the third molars positively influenced the quality of life outcomes in those with minor symptoms of pericoronitis.

How predictable is the position of third molars over time?

PURPOSE

The purpose of this study was to review contemporaneous longitudinal studies focused on changes in the position of third molars.

MATERIALS AND METHODS

A systematic search of the National Library of Medicine (PubMed, http://www.pubmed.gov) and the Cochrane Central Register of Controlled Trials (http://www.mrw.interscience.wiley.com/cochrane) was conducted to identify eligible articles. The inclusion criteria were 1) longitudinal assessment (retrospective or prospective); 2) published in English; and 3) full text available online or at the University of North Carolina Health Sciences Library.

RESULTS

Five studies met the inclusion criteria. The status of third molars with respect to eruption/angulation was operationalized in multiple ways, making any comparison of the frequency of changes in position difficult. The major findings of each study are reviewed.

CONCLUSIONS

Few longitudinal data exist on the changes over time of impacted third molars. Impacted teeth that remain static, with no changes in position or angulation over time, are rare.

Changes over time in the prevalence of caries experience or periodontal pathology on third molars in young adults

PURPOSE

To assess the prevalence of caries experience and periodontal pathology on third molar teeth compared with first and second molars and teeth more anterior from subjects who had data collected over time in a longitudinal clinical study.

PATIENTS AND METHODS

Healthy subjects with 4 asymptomatic third molars and data for at least 4 years after enrollment were included in these analyses. The presence or absence of caries experience on the occlusal surface of the third molars and any surface of the first or second molars was assessed using a visual-tactile caries examination. Full mouth periodontal probing, 6 sites per tooth, was conducted as a measure of clinical periodontal status. The primary outcome measures were at least 1 periodontal probing depth of at least 4 mm versus none, and caries experience versus no caries experience. The prevalence of caries experience and periodontal pathologic findings at follow-up and the relationship of the occurrence between the third molars and teeth more anterior in the mouth were examined using McNemar's statistics.

RESULTS

The follow-up was a median of 6.9 years (interquartile range 4.6 to 7.7 years) for 179 subjects, with a mean age of 29 years. More subjects were female (54%) and white (80%). At follow-up, 85% of the subjects had caries experience detected on the first or second molars, and only 50% had a third molar affected. In contrast, at follow-up, the presence of at least 1 periodontal probing depth of at least 4 mm was marginally more prevalent on the third molars than on the first or second molars (56% and 50%, respectively). Fewer subjects had third molars free of caries experience and periodontal pathology at follow-up compared with at enrollment (28% versus 38%, respectively).

CONCLUSIONS

The prevalence of both third molar caries experience and third molar periodontal pathology increased from baseline to the follow-up examination. At follow-up, the prevalence of caries experience was greater on the first or second molars than on the third molars, and periodontal pathology were greater on the third molars than on the more anterior teeth.

Cryotherapy and topical minocycline as adjunctive measures to control pain after third molar surgery: an exploratory study

PURPOSE

To assess the impact of cryotherapy or topical minocycline on patients' perceptions of recovery from pain after third molar surgery in an exploratory comparative-effectiveness study.

PATIENTS AND METHODS

Subjects aged at least 14 years who were having all 4 third molars removed were enrolled in 3 separate institutional review board-approved studies. Study groups included subjects treated with a passively applied cold wrap for 24 hours postoperatively, subjects treated with topical minocycline during surgery, and subjects enrolled in a nonconcurrent comparison group who had received neither topical minocycline nor directed cryotherapy. Third molar surgery was performed in all cases by trained surgeons using the same protocol. An exact Kruskal-Wallis test was used to compare the distributions of the worst and average pain scores and a Fisher exact test to compare verbal responses from Gracely pain scales among the 3 groups for postsurgical days (PSDs) 1 to 3.

RESULTS

This study comprised 51 cryotherapy subjects (2005-2009), 63 minocycline subjects (2003-2004), and 92 comparison-group subjects (2002-2006) who were treated at academic centers and in community practices across the United States (N = 206). Demographic descriptors were similar among all groups. For PSDs 1 through 3 (unadjusted), the highest scores for worst pain (6-7 [out of 7] on Likert-type scale) were reported less frequently in each of the study groups than in subjects in the comparison group, although the numbers of subjects reporting the highest scores were few. The distribution of pain outcomes was significantly different among the 3 groups for worst pain and affective words on PSD 1 (P = .04 for both). However, the small number of subjects who reported the highest pain scores precluded adequate multivariate statistical analyses for all outcomes on PSD 1 to 3.

CONCLUSIONS

Data from this exploratory study suggest that adjunctive therapy to decrease postoperative pain-cryotherapy or topical minocycline-might be effective at moderating the patient's highest pain levels after third molar surgery. The topic should be studied further in a multicenter, prospective, randomized trial.

Recovery after third-molar surgery: the effects of age and sex

INTRODUCTION

In this study, we assessed the effects of age and sex on quality-of-life recovery after third-molar surgery.

METHODS

Healthy subjects scheduled for removal of third molars were recruited at multiple sites for this study. Each patient was given a condition-specific instrument to be completed each postsurgery day for 14 days. Lifestyle and oral-function recovery were assessed by using a 5-point Likert-type scale. Recovery was defined as the number of days until the patient reported no or little trouble. Recovery from pain was defined as the number of days until no medications were taken. For each quality-of-life item, a Cox regression analysis was performed to assess the effects of age and sex on recovery after controlling for surgical-procedure variables.

RESULTS

Nine hundred fifty-eight subjects treated at 9 academic centers and 12 community practices were enrolled. Except for ability to open the mouth, recovery for all quality-of-life items for those 21 years or older significantly (P < 0.02) lagged behind recovery for younger subjects. Recovery for female subjects was significantly longer than for male subjects for all outcomes (P < 0.01).

CONCLUSIONS

Patients older than 21 and those who are female should be informed before removal of all 4 third molars that their oral function, lifestyle, and pain recovery will be prolonged compared with those who are younger and male.

Visible third molars as risk indicator for increased periodontal probing depth

PURPOSE

To assess the relationship between visible third molars and the periodontal status of teeth more anterior in the mouth from reports that included periodontal probing data for all teeth.

MATERIALS AND METHODS

Each of 4 reports that included periodontal probing data, 6 probing sites for all teeth, including third molars collected by trained, clinician examiners, were briefly summarized. The design, strengths, and weaknesses of each of the 4 studies were compared and summarized. A Forest plot was used to combine the findings from the 4 studies comparing the mean second molar probing depth differences in mm by the presence of at least 1 visible third molar or no visible third molar.

RESULTS

A review of the data from 4 reports, 1 from middle-age adults and 3 from young adults, suggested an association between the visible presence of a third molar and increased periodontal probing depths on teeth more anterior in the mouth, predominately the first and second molars. Coupled with the probing depth around the third molars, the result was an expanded surface area at the biofilm-gingival interface.

CONCLUSIONS

Although all those with retained third molars are not at increased risk, the summary data we have reported suggest that those with a visible third molar are more likely to have greater periodontal probing depths overall, particularly on second molars, and a greater surface area of the biofilm-gingival interface compared with those with no visible third molar.

Second molar periodontal inflammatory disease after third molar removal in young adults

PURPOSE

To assess the prevalence of periodontal inflammatory disease on the distal side of second molars after third molar removal and the association between presurgical and surgical variables and postsurgical periodontal outcomes.

PATIENTS AND METHODS

Data before and after surgery from 2 studies approved by an institutional review board were used. In 1 study, 26 subjects had 4 asymptomatic third molars and in the other 49 subjects had at least 1 mandibular third molar with symptoms of pericoronitis. Full-mouth periodontal probing data, 6 sites per tooth, were obtained as a measurement of periodontal status before and after surgery. A probing depth (PD) ≥4 mm on either of the 2 possible probing sites on the distal side of any second molar (D2M) served as an indicator of periodontal inflammatory disease; periodontal health was defined as all D2M PD <4 mm. Cochran-Mantel-Haenszel row mean score tests compared the subjects' postsurgical periodontal status (all D2M PD <4 mm and at least 1 D2M PD ≥4 mm) with respect to age and time intervals, and the Fisher exact test was used to compare ethnicity, gender, and clinical data at surgery. The McNemar test was used to assess the discordance between subjects' pre- and postsurgical periodontal status. The level of significance was set at .05.

RESULTS

Of the 75 subjects, 52% were women and 65% were white. The median age at surgery was 23.6 years (interquartile range, 20.9 to 26.6 years). At enrollment, 53 of 75 subjects (71%) had at least 1 D2M PD ≥4 mm. Subjects were significantly more likely to have an improved D2M periodontal status after surgery than a deteriorated status (P < .01). Fewer subjects, 17 of 75 (24%), had at least 1 D2M PD ≥4 mm after surgery. D2M PD ≥4 mm was more likely after surgery if presurgical D2M was PD ≥4 mm (P < .01). Gender, ethnicity, age, presurgical symptoms, and data estimating the extensiveness of surgery were not significantly associated with postsurgical D2M periodontal outcomes.

CONCLUSIONS

After third molar removal, periodontal inflammatory disease on the distal of D2Ms was detected significantly less often. None of the variables examined except for presurgical presence of D2M PD ≥4 mm were significantly associated with postsurgical D2M periodontal inflammatory disease.

Third molar caries experience in middle-aged and older Americans: a prevalence study

PURPOSE

To assess the prevalence of third molar caries experience in a middle-aged and older population and the relationship of these findings to caries experience in teeth more anterior in the mouth.

PATIENTS AND METHODS

Data from 6,550 Dental Atherosclerosis Risk in Communities study participants aged 52 to 74 years who underwent a clinical examination for coronal caries experience were available for these analyses. Subjects with visible third molars (N = 2,003) were divided based on third molar coronal caries experience on at least 1 third molar: no carious/decayed coronal surface (DS) or at least 1 coronal DS and no filled coronal surface (FS) or at least 1 coronal FS. Coronal DS and FS were also calculated for more anterior teeth. Covariates included ethnicity, gender, age, body mass index, education, income, smoking status, and diabetes diagnosis. Subject level outcomes for third molar and more anterior teeth were compared by descriptive statistics and chi(2) or t tests with statistical significance set at P less than .05. Multivariate modeling was performed to adjust outcome variables for covariates.

RESULTS

Third molar caries experience was detected in 77% of subjects and was significantly associated with caries experience in more anterior teeth and white race (P < .01). Caries experience was detected in only third molars in 1% of subjects, and 1% of subjects were caries free. Subjects with less education (20%) and lower income (19%) were significantly more likely to have DS detected compared with subjects with more education (6%) and higher income (5%) (P < .01). Conversely, subjects with more education (75%) and higher income (77%) were significantly more likely to have FS detected compared with subjects with less education (55%) and lower income (60%) (P < .01).

CONCLUSIONS

Third molar coronal caries experience was significantly associated with caries experience in teeth more anterior in the mouth in this middle-aged and older population.

Third molars and periodontal pathologic findings in middle-age and older Americans

PURPOSE

To assess the association between the visible presence of third molars and the severity of periodontal pathologic findings on teeth more anterior in the mouth.

PATIENTS AND METHODS

The present analysis included dentate participants, 52 to 74 years old, from the Dental Atherosclerosis Risk in Communities study who had undergone an oral examination that included periodontal probing depths (PDs) on all visible teeth, including any third molars. A PD of 4 mm or more and a clinical attachment level of 3 mm or greater were indicator variables for periodontal pathologic features. Explanatory variables were the presence or absence of visible third molars. The covariates included gender, ethnicity, age, income level, education, and smoking status. The outcome variables for periodontal pathologic features were the mean PD, extent (percentage of probing sites) of PDs of 4 mm or more, and the extent (percentage of probing sites) of a clinical attachment level of 3 mm or more. The outcomes between those with and without visible third molars were compared using descriptive statistics and chi-square tests, with significance set at P = .05. Multivariate modeling was performed using Statistical Analysis Systems SAS Proc GLM (SAS Institute, Cary, NC) to calculate the least squared means, adjusting for the study outcome variables and covariates.

RESULTS

The Dental Atherosclerosis Risk in Communities study sample included 6,793 subjects; 80% were white and 19% were black. Most (53%) were 62 to 74 years old and female (54%). Of the 6,793 participants, 2,035 (30%) had at least 1 visible third molar. The presence of a visible third molar was significantly associated with male gender, black race, age younger than the mean of 62.4 years, greater income, and never smoking (all P < .01). A greater mean PD for the first and second molars, the extent of PD of 4 mm or more at the first and second molars, and the extent of a clinical attachment level of 3 mm or more at the first and second molars were all significantly associated with the presence of a visible third molar in the unadjusted and adjusted models.

CONCLUSIONS

In these middle-age and older Americans, the presence of a visible third molar was significantly associated with more severe periodontal disease on teeth more anterior in the mouth compared with those subjects with no visible third molars.

Light intensity and social communication between hens

1. The effect of light intensity on social communication in laying hens was investigated experimentally by comparing the transmission and detection of social signals between familiar and unfamiliar hens of similar or unequal rank in a competition for food. 2. The experimental method consisted of mutual inspection by a pair of hens at short range (approximately 24 cm), followed by a competition at a feed trough from which only one hen could eat a favoured food. The relative rank of a hen was inferred from success in this competition. 3. The relative rank of individual hens within 5 groups, each of 6 adult laying hens, was determined to identify those of high and low rank within their home group. 4 Social communication between pairs of either unfamiliar or familiar hens of either similar or unequal rank (highest and lowest ranking within their home groups) was then assessed under light intensities of 1, 5, 20 and 100 lux with all other cues present. Only the dimmest light of 1 lux perturbed some aspects of the competition for food. 5. The findings provide scientific justification, in part, for the current legal requirement in England for 'all hens to see other hens' by specifying a minimum light intensity of at least 5 lux for hens kept in close proximity to each other.

Recurrent Thunderclap Headaches and Multilobar Intracerebral Haemorrhages: Two Cases of Reversible Cerebral Vasoconstriction Syndrome (RCVS)

We describe two patients with thunderclap headaches due to reversible cerebral vasoconstriction syndrome (RCVS). The first patient illustrates multilobar intracerebral haemorrhages as an under-appreciated feature of RCVS, and the second illustrates recurrent thunderclap headache (presumed recurrent RCVS) after a long interval of 4 years. These cases demonstrate the spectrum of presentation of RCVS, a clinically under-recognized condition.

Comparison of periodontal inflammatory disease in young adults with and without pericoronitis involving mandibular third molars

PURPOSE

To compare the prevalence and severity of periodontal inflammatory disease in subjects with pericoronitis involving a mandibular third molar and those without pericoronitis.

PATIENTS AND METHODS

Data obtained from healthy adults consecutively enrolled in an institutional review board-approved trial with pericoronitis affecting at least 1 mandibular third molar (study group) were compared with data obtained during the same time frame from subjects without pericoronitis enrolled in a longitudinal third molar monitoring study (comparison group). The periodontal status of each subject was classified based on periodontal probing depths (PD): all PD <4 mm, no disease; 1 to 3 PD >or=4 mm, incipient disease; at least 4 PD >or=4 mm, early disease. Full mouth periodontal probing data were obtained as clinical measures of periodontal status. Data were aggregated to the subject level for the third molar region, the 6 third molar probing sites and the 2 second molar distal probing sites, the non-third molar region, and all remaining probing sites. The prevalence of disease in the study and comparison groups were compared with the Fisher's exact test. As an indicator of disease severity, the number of PD >or=4 mm in the 2 groups were compared by the Kruskal-Wallis test. Level of significance was set at P values less than .05.

RESULTS

Median age of the 56 subjects with pericoronitis was 23.3 years (IQR 21.3-26.0 years). Fifty-five percent were Caucasian, 16% African American, and 22% Asian. Males and females were almost equally represented in the study group and in the comparison group. The 194 subjects enrolled without pericoronitis were significantly older (32.8 years; IQR 27.2-40.0 years; P < .001). Eighty-four percent were Caucasian, 10% African American, and 4% Asian. The proportion of subjects with periodontal inflammatory disease in the third molar region was significantly different between the study and comparison groups. Thirty-one percent of the subjects with pericoronitis had incipient and 55% early disease in the third molar region compared with 25% with incipient and 38% with early disease among subjects without pericoronitis (P = .003). The pattern was similar, but the proportion of subjects was not significantly different between the groups for the non-third molar region. In the study group, 32% had incipient disease and 32% early disease compared with 27% with incipient disease and 22% with early disease in the comparison group (P = .09). The median number of PD >or=4 mm for all teeth differed significantly for subjects with and without pericoronitis (median 5 [IQR 3-9] vs 3 [IQR 0-8], respectively; P = .03).

CONCLUSION

Pericoronitis involving mandibular third molars may reflect more underlying periodontal inflammatory disease in affected young adults than might be found in young adults with retained third molars and no pericoronitis.

Evidenced-based decision making: the third molar

The American Association of Oral and Maxillofacial Surgeons (AAOMS) has been at the forefront of formal evidence-based dentistry with such projects as the Parameters of Care: Clinical Practice Guidelines for Oral and Maxillofacial Surgeons, the AAOMS Outcomes Assessment Program, the AAOMS Third Molar Clinical Trial, and the AAOMS "White Paper on Third Molar Data." This article reviews these evidence-based resources to provide a consensus of opinion for the management of the third molar.

Controlled atmosphere stunning of broiler chickens. II. Effects on behaviour, physiology and meat quality in a commercial processing plant

1. The effects of controlled atmosphere stunning on behavioural and physiological responses, and carcase and meat quality of broiler chickens were studied experimentally in a full scale processing plant. 2. The gas mixtures tested were a single phase hypercapnic anoxic mixture of 60% Ar and 30% CO(2) in air with <2% O(2), and a biphasic hypercapnic hyperoxygenation mixture, comprising an anaesthetic phase, 40% CO(2), 30% O(2), 30% N(2), followed by an euthanasia phase, 80% CO(2), 5% O(2), 15% N(2). 3. Birds stunned with Ar + CO(2) were more often observed to flap their wings earlier, jump, paddle their legs, twitch and lie dorsally (rather than ventrally) than those stunned with CO(2) + O(2). These behaviours indicate a more agitated response with more severe convulsions during hypercapnic anoxia, thereby introducing greater potential for injury. 4. Heart rate during the first 100 s of gas stunning was similar for both gases, after which it remained constant at approximately 230 beats/min for CO(2) + O(2) birds whereas it declined gently for Ar + CO(2) birds. 5. In terms of carcase and meat quality, there appeared to be clear advantages to the processor in using CO(2) + O(2) rather than Ar + CO(2) to stun broiler chickens, for example, a much smaller number of fractured wings (1.6 vs. 6.8%) with fewer haemorrhages of the fillet. 6. This study supports the conclusions of both laboratory and pilot scale experiments that controlled atmosphere stunning of broiler chickens based upon a biphasic hypercapnic hyperoxygenation approach has advantages, in terms of welfare and carcase and meat quality, over a single phase hypercapnic anoxic approach employing 60% Ar and 30% CO(2) in air with <2% O(2).

Controlled atmosphere stunning of broiler chickens. I. Effects on behaviour, physiology and meat quality in a pilot scale system at a processing plant

1. The effects of controlled atmosphere stunning on the behaviour, physiology and carcase and meat quality of broiler chickens were studied experimentally in a pilot scale plant. 2. Gas mixtures tested were: single phase anoxic mixture (90% Ar in air, <2% O(2)); single phase hypercapnic anoxic mixture (60% Ar, 30% CO(2) in air, <2% O(2)); and biphasic hypercapnic hyperoxygenation mixture (anaesthetic phase, 40% CO(2), 30% O(2), 30% N(2); euthanasia phase, 80% CO(2), 5% O(2), 15% N(2)). 3. Anoxic stunning resulted in the least respiratory disruption, mandibulation and motionlessness, but most head shaking, leg paddling and twitching. Loss of posture occurred soonest with hypercapnic anoxia with the earliest and most twitching and wing flapping in individuals and earliest leg paddling. Biphasic birds were most alert, exhibited most respiratory disruption and mandibulation, and had the latest loss of posture and fewest, but longest bouts of wing flapping and least leg paddling and twitching. 4. Significant and sudden bradycardia and arrhythmia were evident with all gas mixtures and were not related solely to anoxia or hypercapnia. Birds stunned by Ar anoxia showed a slightly more gradual decline from baseline rates, compared with hypercapnic mixtures. 5. Few differences were found between gas mixes in terms of carcase and meat quality. Initial bleeding rate was slowest in biphasic-stunned birds, but total blood loss was not affected. Acceleration of post-mortem metabolism in anoxic-stunned birds was not sufficient to allow de-boning within 5 h without the risk of tough meat. 6. On welfare grounds and taking into account other laboratory and field studies, a biphasic method (using consecutive phases of anaesthesia and euthanasia) of controlled atmosphere stunning of broilers is potentially more humane than anoxic or hypercapnic anoxic methods using argon or nitrogen.

Changes Over Time in Position and Periodontal Probing Status of Retained Third Molars

PURPOSE

This study was designed to assess changes over time in third molar position relative to the occlusal plane and in the periodontal probing status of third molars in asymptomatic subjects who had at least 1 third molar below the occlusal plane at baseline and retained all third molars to follow-up.

PATIENTS AND METHODS

Between 1998 and 2002, healthy subjects with 4 asymptomatic third molars and adjacent second molars were enrolled in an institutional review board (IRB)-approved longitudinal study. Clinical and radiographic data of 146 subjects who had at least 1 third molar not fully erupted at baseline with at least 2-year follow-up were analyzed. At baseline and longest follow-up, full mouth periodontal probing, 6 sites per tooth, including third molars was conducted. An indicator variable was used to record periodontal status (probed, not probed) for each third molar. A periodontal probing depth (PD) greater than or equal to 4 mm in the third molar region was considered indicative of periodontal pathology. Panoramic radiographs were analyzed to assess whether unerupted third molars erupted to the occlusal plane. To assess descriptively the influence of age and length of follow-up on the change in third molar position and periodontal status, subjects were stratified by age at enrollment as younger (<25 years) or older (>or=25 years) and by length of follow-up as shorter follow-up (2 to <4 years), or longer follow-up (4 or more years). Because of the small sample sizes in each stratum, analyses are limited to descriptive statistics only.

RESULTS

Sixty-six percent of the 146 subjects were less than 25 years old at enrollment. The majority were female and Caucasian. Sixty-eight percent of the 97 younger subjects and 43% of the 49 older subjects presented at baseline with all 4 third molars not fully erupted. Of 584 third molars evaluated, 79% were not fully erupted at baseline; of 462 molars, 80% could not be probed at baseline. Eruption to the level of the occlusal plane occurred in all 4 strata although only a third of the unerupted molars reached the occlusal plane even in the younger subjects with the longer follow-up. Of 369 molars that could not be probed at baseline, approximately 35% could be probed at follow-up with the highest percentage of change in the older subjects with the longer follow-up (46%).

CONCLUSIONS

The anatomic position of third molars was not static over time even if subjects were greater than 25 years old. Thus, unerupted third molars should be monitored for changes in position and periodontal pathology as long as the teeth are retained.

Changes in third molar and nonthird molar periodontal pathology over time

PURPOSE

The purpose of this study was to assess changes in periodontal probing depth (PD) over time for third molar and nonthird molar regions in young adults.

PATIENTS AND METHODS

The data were obtained from healthy subjects with 4 asymptomatic third molars, enrolled in an IRB-approved longitudinal trial. Demographic and oral health data were collected at baseline. Full-mouth PD, 6 sites per tooth, was conducted to determine periodontal status at baseline and at longest follow-up. The third molar region was defined as the PD for 6 sites around the third molars and the 2 sites on the distal of the second molars. The nonthird molar region was defined as the remainder of the PD sites in the mouth. The primary outcome measures for this study were the occurrence of a PD greater than or equal to 4 mm and the increase in PD of at least 2 mm in the third molar and nonthird molar regions. Changes from enrollment to longest follow-up were compared by the binomial or McNemar's test. Level of significance was .05.

RESULTS

Data from 195 subjects were available, and the median follow-up was 5.9 years (interquartile range [IQ], 4.6 to 6.9 years). Median age at enrollment was 26.2 years (IQ, 22.0 to 34.0 years); 52% were female, 84% were Caucasian, and 10% were African American. The proportion of subjects with at least 1 involved site in nonthird molars increased significantly from baseline to follow-up, 36% to 49% (P < .01), reflecting mostly changes in mandibular nonthird molars, 33% to 48% (P < .01). Of the 122 subjects who presented at baseline with at least 1 PD greater than or equal to 4 mm in the third molar region, the proportion of subjects with at least 1 involved site in nonthird molars increased significantly from baseline to follow-up, 48% to 59% (P = .05), also reflecting mostly changes in mandibular nonthird molars, 44% to 59% (P = .05).

CONCLUSION

In this unique longitudinal clinical study of early periodontal disease in young adults, periodontal pathology worsened over time for nonthird molars. This was more likely if PD greater than or equal to 4 mm was detected in the third molar region.

The Oral and Systemic Impact of Third Molar Periodontal Pathology

PURPOSE

Analyze in pregnant subjects the relationship between third molar periodontal pathology, and subjects' overall periodontal status. Assess also, the associations between postpartum periodontal status by jaw and a systemic impact, preterm birth, or elevated serum C-reactive protein (CRP).

PATIENTS AND METHODS

Data were from an IRB-approved study, Oral Conditions and Pregnancy. In this clinical study, full-mouth periodontal examinations including third molars were conducted at greater than 24 weeks of pregnancy and again within 72 hours of delivery. For our analyses, mean periodontal probing depth (PD) by visible tooth and by jaw were calculated at enrollment and postpartum. Subjects were categorized by 3 broad levels of periodontal health, considered the primary outcome variable. The primary predictor variable for levels of periodontal health was the presence or absence of visible third molars. Mean periodontal probing depth in the mandible or maxilla at term was considered an indicator of a possible risk of systemic exposure, increasing the odds of preterm birth, less than 37 weeks gestation, or elevated serum CRP levels. Chi-square and t tests were used to determine statistical significance, .05. Significant predictor variables were included in multivariable models. Unconditional logistic multivariate models were used to derive odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Data from examinations at enrollment and postpartum were available for 1,020 and 891 subjects, respectively. Visible third molars were detected in 405 subjects at enrollment and in 360 subjects at term. No subjects had third molars removed during the study. At enrollment and postpartum, subjects with visible third molars were significantly more likely to have moderate/severe periodontal disease, 23.5% versus 8.5%, and 18.3 versus 9.4%, respectively. Mean PD was significantly greater for maxillary and mandibular molars than for more anterior teeth, P < .01. In both jaws, mean PD tended to be progressively greater from first to third molars. No differences were found in mean PD by jaw. In subjects with visible third molars, adjusting for the severity of mandibular periodontal disease, the level of maxillary periodontal disease was significantly associated with preterm birth, P < .01, OR 2.6 (95% CI 1.1-6.8), or the upper quartile of serum CRP at term, at least 23.0 mg/L postpartum, P = .05, OR 2.5 (95% CI 1.2-5.1).

CONCLUSIONS

Subjects' detected levels of periodontal disease were greater at enrollment and postpartum if visible third molars were detected.

Third Molars and Progression of Periodontal Pathology During Pregnancy

PURPOSE

This study was conducted to evaluate the association between third molar periodontal pathology at enrollment and periodontal disease progression during pregnancy.

PATIENTS AND METHODS

The data were derived from patients in an institutional review board-approved prospective study known as the Oral Conditions and Pregnancy (OCAP) study. Demographic, health behavior, and medical history data were obtained from medical records. Full-mouth periodontal examinations of 6 periodontal probing sites for each visible tooth, including third molars, were conducted at less than 26 weeks of pregnancy and within 72 hours postpartum. The primary outcome variable was periodontal progression (4 or more probing sites with at least a 2 mm increase in probing depth (PD), all at least 4 mm deep), between the enrollment and postpartum examinations. The primary predictor variables at enrollment were at least 1 PD >or=4 mm around the third molars, and the upper tertile of the number of third molar probing sites recorded as bleeding on probing (BOP). Bivariate analyses were performed for baseline characteristics. The chi2 test was used to determine statistical significance (P = .05). Significant variables were included in unconditional logistic multivariable models to derive relative risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

Data from enrollment and term were available for 360 subjects with visible third molars (mean age, 27.3 years; standard deviation, 5.5 years). At the postpartum examination, 122 subjects (34%) demonstrated periodontal progression. These subjects included 74 of the 176 subjects (42%) in whom a third molar PD >or=4 mm was detected at baseline and 48 of the 184 (26%) without third molar PD >or=4 mm (P = .001). Periodontal progression was found in 40 of the 77 subjects (52%) who were in the upper tertile of the number of third molar probing sites exhibiting BOP at enrollment versus 82 of the 203 (29%) in the lower tertiles (P = .0002). In multivariable models, either third molar PD >or=4 mm at enrollment (RR = 1.4; 95% CI = 1.1 to 2.0) or third molar bleeding on probing (RR = 1.7; 95% CI = 1.3 to 2.3) was associated with periodontal disease progression.

CONCLUSION

Third molar periodontal pathology appears to be a significant risk indicator for periodontal disease progression during pregnancy.

Risk Indicators for Third Molar Caries and Periodontal Disease in Senior Adults

PURPOSE

This study was designed to identify risk indicators for the prevalence at enrollment and incidence over 36 months of periodontal pathology and coronal caries experience affecting third molars in a community-based study of people over 65 years of age.

SUBJECTS AND METHODS

Data from a subsample of 810 dentate subjects from the Piedmont 65+ Study were available for analyses. All visible teeth were examined. Periodontal probing measures were taken at 2 sites, mesiobuccal and buccal/facial. Clinical data on caries experience were collected by visual-tactile examination. At enrollment, 340 subjects had at least 1 visible third molar; all were examined for caries experience. Periodontal probing measures were available for 277 of these same subjects. The significance of the possible risk indicators for periodontal pathology and caries affecting third molars was determined by chi(2) tests. Statistical significance was set at .05. Logistic multivariable models were used to derive odds ratios and 95% confidence intervals.

RESULTS

African-American subjects were more likely to have visible third molars (P < .01). Caucasian subjects were more likely to have third molar coronal caries experience (P < .01), as were subjects with greater than a high school education and those with a dental visit within 3 years (both P < .01). However, African American subjects were more likely to have periodontal pathology, CALs >/= 3 mm on third molars (P < .01), as were those who used tobacco (P < .01). None of the other risk indicators we studied were associated with progression of periodontal pathology or coronal caries experience on visible third molars.

CONCLUSION

In this population study of senior adults, Caucasians and African Americans appear to have different levels of risk for caries experience and periodontal pathology affecting retained third molars.

Third Molar Root Development and Recovery from Third Molar Surgery

PURPOSE

This study was conducted to determine if the completeness of the root formation of mandibular third molars prior to removal affected clinical and health-related quality of life (HRQOL) recovery.

PATIENTS AND METHODS

Data from HRQOL responses from patients and clinical outcome data were available after third molar surgery conducted by surgeons in community practice and academic centers. The root development of each mandibular third molar on presurgery panoramic radiographs for these patients was assessed by trained clinician observers. Patients were categorized as those with complete root formation (both mandibular third molars had 100% completely formed roots) or as those with incomplete root formation (at least 1 mandibular third molar not completely formed). The proportion of patients who experienced delayed clinical or HRQOL recovery that exceeded a clinically relevant criterion value were compared for these 2 groups of patients using chi2 statistics. Level of significance was set at 0.05.

RESULTS

Both mandibular third molars had 100% completely formed roots in 118 patients; at least 1 mandibular third molar was not completely formed in 218 patients. If patients had a mandibular third molar with roots less than 100% complete, they more likely: were female (65% vs 58%), were less than 25 years old (95% vs 54%), P < .01, and had not finished high school (59% vs 28%), P < .01. For those with incomplete root formation, bone removal for both mandibular third molars was more likely (84% vs 67%), P < .01, and the surgeons' overall estimate of degree of difficulty was greater (14/28 vs 12/28), P = .02. Median surgery time did not differ between groups. The proportion of patients who experienced delayed clinical or HRQOL recovery did not differ between the incomplete and complete root formation groups.

CONCLUSIONS

Incomplete lower third molar root formation presurgery may not be a predictor of better or worse clinical or HRQOL recovery after surgery. Other clinical, demographic, and health indicators should influence surgeons' recommendations and patients' decisions regarding third molar treatment including surgery.