Inferior alveolar nerve block and third-molar agenesis: a retrospective clinical study.

BACKGROUND: Children often receive inferior alveolar nerve blocks (IANBs) when their third molars are just beginning to develop. The location of the third-molar follicle is close to where the needle penetrates during an IANB. The authors examined the possible association between IANBs and missing third molars. METHODS: The authors examined 439 potential sites of third-molar development for evidence of third-molar follicles on panoramic radiographs of randomly selected children 7 years and older. The authors conducted a statistical comparison of the incidence of missing third-molar follicles in a control group of children who had no history of receiving IANBs with children in a test group who had a definitive history of receiving IANBs by means of generalized estimating equations. RESULTS: The authors found a statistically significant greater incidence of missing third-molar follicles in mandibular quadrants that had a definitive history of receiving IANBs compared with mandibular quadrants that had no history of receiving IANB. CONCLUSION: IANBs administered to young children when the third-molar tooth bud is immature may stop third-molar development. Owing to the significant clinical implications, further research is needed to verify these results. PRACTICAL IMPLICATIONS: Dentists inadvertently may be stopping the development of third molars when administering IANBs to children.

Prevention of third molar development in dog with long pulse diode laser: a preliminary report.

INTRODUCTION: Wisdom teeth continue to plague man with a high rate of frequency. It may be possible to prevent their development in children at an early age with a non- or minimally invasive technique, even before the tooth begins to form, by treating the soft tissue overlying the site of their development. A previous study that treated the intra-oral soft tissues of newborn rats with a 20 watt diode laser stopped third molar development up to 80% of the time with minimum observable side effects. This brief report describes a similar use of the diode laser in a limited number of young beagle pups. It is the first reported attempt at preventing third molar development in an animal model close in size to man. MATERIALS AND METHODS: Four 6-7 week old beagle pups were treated on one side of their mandibles with either a 20 or a 100 watt, 800 nm diode laser at a time third molar tooth buds are just beginning to form under the oral mucosa. Six months following treatment, the pups were examined intra-orally and radiographically for evidence of third molar formation. RESULTS: The two intra-oral sites that received the 20 watt diode laser treatment showed normal third molar development. The two intra-oral sites that received the 100 watt diode laser treatment did not develop third molars. CONCLUSIONS: The diode laser may be capable of selectively stopping third molar development and further studies are warranted.

Prevention of third molar tooth development in neonate rat with a long pulse diode laser.

BACKGROUND AND OBJECTIVES: Third molars (wisdom teeth) in humans have limited functional value and cause a high frequency of morbidity. A window of opportunity exists to stop their development. The purpose of this study is to evaluate whether a long pulse diode laser can selectively prevent third molar development in a rat animal model. STUDY DESIGN/MATERIALS AND METHODS: The study calculated theoretical diode laser parameters and irradiated 2- to 4-day-old rat pups in the posterior aspects of the oral cavity near the time of tooth bud initiation. Rats were sacrificed at 35-50 days and examined intraorally and radiographically for third molar development. Control and treated sides were compared histologically. RESULTS: Nearly half of the maxillary third molars and 80% of the mandibular third molars were selectively prevented from developing using a 20 W diode laser with infrequent, minor adverse effects on maxillary jaw growth. CONCLUSIONS: This study confirms the hypothesis that controlled, non-invasive laser treatment delivered on the surface of the oral mucosa near the site of tooth bud formation can selectively achieve third molar agenesis. It also offers hope that further innovative studies may bring about a safe, non-invasive laser treatment to selectively prevent third molar development in humans.

Selectively preventing development of third molars in rats using electrosurgical energy.

BACKGROUND: Third molars are teeth with questionable value. People who never develop third molars avoid confronting the disease and pain these teeth often cause. Since third molars do not begin to develop until children are approximately five years of age, a window of opportunity exists to therapeutically prevent this tooth's development. The dentition of neonate rats possess developmental stages of molars similar to that of five-year-old children. This pilot study tests the hypothesis that third molars can be selectively prevented from developing. METHODS: Thirty-three neonate rats received a momentary pulse of electrosurgical energy to one of their maxillary tuberosities. The tuberosities on the contralateral sides received no treatment. Intraoral and radiographic examinations of sacrificed animals occurred when they were between 47 and 52 days old. Several tuberosity areas from sacrificed animals underwent histologic examination. RESULTS: Ten rats showed no intraoral or radiographic evidence of third molar development, and six developed smaller-than-normal third molars. Development of the maxilla also was affected frequently. One treated tuberosity area that was missing a third molar showed no histologic evidence of tooth-forming tissues, cyst formation or other significant abnormal tissue changes. CONCLUSIONS: Maxillary third molars can be selectively prevented from developing in rat pups at or near the time of tooth bud initiation; however, electrosurgical energy is too powerful and uncontrollable to reliably confine its damage to only the tooth-forming tissues. CLINICAL IMPLICATIONS: Third molars may be able to be selectively prevented from developing in growing children near the time of tooth bud initiation if less-differentiated precursor tooth-forming tissues can be selectively targeted.

The unresolved problem of the third molar: would people be better off without it?

BACKGROUND: Third molars are teeth that have little functional value and a relatively high rate of associated pain and disease. Their value as part of the dentition of modern people is dubious. TYPES OF STUDIES REVIEWED: The authors review the evolution, development, morbidity and treatment of third molars. They assess the value of third molars in the 21st century and describe the risks these teeth pose when they develop in the dentition. CONCLUSIONS: There is a mandate for the dental profession to improve health outcomes and quality of life. The prevention of third molar-related morbidity should be included in dental research efforts. The authors suggest that novel preventive methodologies be developed to alleviate the problems third molars pose. One potential methodology suggested is intentional therapeutic agenesis of this tooth. CLINICAL IMPLICATIONS: Prevention of third molar development early in life, even before tooth bud initiation, could dramatically improve health care outcomes for millions of people.